Towing with Honda Accord - NO PROBLEM - PICK THE RIGHT BOAT!!!!!!!!!!!!!!
Jim Casto
> Has anyone had experiences towing a 2000-3000lb boat with a Honda Accord?
> I would like to purchase an 18' pleasure boat and tow it with an Accord.
> I purchased a Draw-Tite class 1 custom hitch which looks rugged enough to
> pull well over its 2000lb rating (a local boat dealer said that he's
> pulled 3000lb boats with a class 1 hitch for years with no problem.)
And finally decides :
>As soon as I pay off the loan on my new truck, I'll be
>able to buy a boat. See y'all on the water in 5 years! :-(
Steve, I for one, think this is very sad. Apparently none of us
convinced you that "18 foot pleasure boats" don't have to weigh
2000-3000 lbs, and that lots of pleasure can be gained from boats which
can be towed by a Honda Accord. I can think of any number of small
SAILboats, and catamarans especially, that fit this category. Just
expand your horizons beyond lead-based (keelboats) or iron-based
(internal combustion engines) technologies, and you'll be surprised at
how much water-borne pleasure you can have on an Accord-sized budget.
Instead of solving your problem - how to get on the water with only an
Accord as tow vehicle, we all told you horror stories about towing, and
scared you off the water for another 5 years.
BTW, I believe the 2000 lb rating for class 1 hitch comes from the
rating of the 1 7/8" ball, not from the hitch itself. I believe if you
use a 2" ball, you get 3000 lb rating, and hitch can take it no
problem, like the dealer said.
----------------------------------------------
Jim Casto
rtc...@sps.mot.com
----------------------------------------------
Bill Walker
Casto) wrote:
[some good stuff about maybe choosing a lighter boat instead of a heavier
tow vehicle, followed by]
>
> BTW, I believe the 2000 lb rating for class 1 hitch comes from the
> rating of the 1 7/8" ball, not from the hitch itself. I believe if you
> use a 2" ball, you get 3000 lb rating, and hitch can take it no
> problem, like the dealer said.
While this may be the case with _some_ class 1 hitches (and I'm extremely
skeptical that it is), it sure isn't the case with all of them. Have you
ever looked at the attachments of a class 1 hitch? I've seen some where
the braces attach to the external body sheetmetal. Very weak.
Re your assertion about ball size, I believe a class 1 hitch typically has
a hole for a "small" shank (can't recall the exact sizes at the moment),
while class 2 and up have larger holes and take larger shanks. You can get
both 1-7/8" and 2" balls with either size shank (I've owned all four
possible combinations at various times). I'm sure the smaller shank size
has something to do with the class 1 rating, so even if you put a 2" ball
on a class 1 hitch, it'll still be a small shank, and will still be a class
1 hitch rated for no more than 2000 lbs. In my experience, this rating is
stamped the hitch draw bar of class 1 hitches. I've never seen one that
said "unless a 2" ball is used".
----------
Bill Walker - WWa...@qualcomm.com - QUALCOMM, Inc., San Diego, CA USA
"First thing we do, we kill all the lawyers." - Shakespeare
William Janssen
>From: rtc...@email.sps.mot.com (Jim Casto)
>Subject: Re: Towing with Honda Accord - NO PROBLEM - PICK THE RIGHT
>Date: Mon, 16 May 1994 16:00:32 GMT
>Instead of solving your problem - how to get on the water with only an
>Accord as tow vehicle, we all told you horror stories about towing, and
>scared you off the water for another 5 years.
>BTW, I believe the 2000 lb rating for class 1 hitch comes from the
>rating of the 1 7/8" ball, not from the hitch itself. I believe if you
>use a 2" ball, you get 3000 lb rating, and hitch can take it no
>problem, like the dealer said.
>----------------------------------------------
>Jim Casto
>rtc...@sps.mot.com
>----------------------------------------------
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! B.S. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I bent a 3500 lb. ball towing only 1500 lbs.
(up a very steep , rough , hill)
Don't overload your hitch by putting a bigger ball on a small hitch !
However , there are lighter 18 foot boats that you can probably tow
behind your Honda Accord.
............................... W. Janssen .
Mark Armstrong soft
>
>> Has anyone had experiences towing a 2000-3000lb boat with a Honda Accord?
>> I would like to purchase an 18' pleasure boat and tow it with an Accord.
>
>
>>As soon as I pay off the loan on my new truck, I'll be
>>able to buy a boat. See y'all on the water in 5 years! :-(
>
>Steve, I for one, think this is very sad. Apparently none of us
>convinced you that "18 foot pleasure boats" don't have to weigh
>2000-3000 lbs, and that lots of pleasure can be gained from boats which
>can be towed by a Honda Accord.
I know of the perfect boat, just go buy one of those jet skies.
Buy a noisy one, sailor prefer noisy ones since they can hear you
comming.
sorry...
You could try to find a marina and dry dock your boat. No need
to haul it around plus it would be nice to have a "home" base
when spending the day out on the boat. How do small boats manage
without having a head aboard?
______________________________________________________________
Mark Armstrong
m...@raster.Kodak.COM
______________________________________________________________
Brian_Smith
: I know of the perfect boat, just go buy one of those jet skies.
: Buy a noisy one, sailor prefer noisy ones since they can hear you
: comming.
: sorry...
: You could try to find a marina and dry dock your boat. No need
: to haul it around plus it would be nice to have a "home" base
: when spending the day out on the boat. How do small boats manage
: without having a head aboard?
The boats manage fine, it's their crews that have the problems!. I'm sorry
too.
B.S!
Mark Crafts
:>>As soon as I pay off the loan on my new truck, I'll be
:>>able to buy a boat. See y'all on the water in 5 years! :-(
:>Steve, I for one, think this is very sad. Apparently none of us
:>convinced you that "18 foot pleasure boats" don't have to weigh
:>2000-3000 lbs, and that lots of pleasure can be gained from boats which
:>can be towed by a Honda Accord. I can think of any number of small
:>SAILboats, and catamarans especially, that fit this category. Just
:>expand your horizons beyond lead-based (keelboats) or iron-based
:>(internal combustion engines) technologies, and you'll be surprised at
:>how much water-borne pleasure you can have on an Accord-sized budget.
:>Instead of solving your problem - how to get on the water with only an
:>Accord as tow vehicle, we all told you horror stories about towing, and
:>scared you off the water for another 5 years.
Oh dear - Jim's right.
I forget whether the original poster wanted to tow a sailboat or a powerboat,
but I towed a 17' Wahoo behind a Ford Taurus for a couple of years without
a problem. It and the trailer and the gear weighed maybe 1400 lbs. Great
fishing/ski boat! (I even took it to the Bahamas!) Having in-depth
knowledge of the construction of the Wahoo however, I'd have to recommend
the 17' Whaler....Anyway, the point is instead of settling for a mediocre
boat or (ugh!) no boat at all, perhaps you should look at some of the
lighter boats that will serve your purpose just as well..
Mark
Now - get your butt on the water! :)
--
<><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
Mark Crafts Melbourne FL
cra...@mary.iia.org
piranha
to forego the purchase of a boat until his new tow vehicle is paid
off, in 5 years or so. (nice guilt trip there, by the way. :-)]
while that likely will save your honda's life, and possibly
yours, there are alternatives -- i am not sure you were en-
tirely serious so i didn't respond right away. but what the
hey.
why must it be a 18 footer that weighs up to 3000 lbs? you
could always buy the size boat the honda _can_ tow. or you
could find a marina and rent a slip. or drydock the boat.
(in central illinois, umm. where were you planning to do
your boating, lake shelbyville? or lake michigan for some
real wave action?)
-piranha
Steve Zinski
In a previous article, p00...@psilink.com ("piranha") says:
> why must it be a 18 footer that weighs up to 3000 lbs? you
> could always buy the size boat the honda _can_ tow. or you
> could find a marina and rent a slip. or drydock the boat.
> (in central illinois, umm. where were you planning to do
> your boating, lake shelbyville? or lake michigan for some
> real wave action?)
>
> -piranha
I have been looking at new/used SeaRay and Rinker boats. I want to stick
with a good quality, well built boat (sturdy fiberglass hull) with a
6-Cyl Mercury I/O (4-Cyl is too small and takes too much abuse). Both the
18' SeaRay and 18' Rinker would weigh about 2,200 lbs (dry weight without
trailer). Add an 800 lb trailer, fuel, and gear and I'm over 3,000 lbs.
I would mostly run the boat in Lake Clinton or Lake Shelbyville. I live
too far from Chicago (Lake Michigan). From what it would cost me to
dry-dock or rent a slip, I could be paying off a loan for a good (used)
tow vehicle.
I think the solution to my problem is to buy an inexpensive 4WD pickup
truck and use it as my tow/utility vehicle. I definately don't want to
buy a "light" boat (aka Bayliner with paper-thin hull)... I want a good,
solid, boat that will last me 20 or 30 years.
Thanks again for everyone's input on this matter... and if you know of
anyone selling a used SeaRay in good condition... ;-)
--Steve
--
=================================================================
== Steven C. Zinski - N9VAH == szi...@prairienet.org ==
== Champaign, Illinois, USA == N9VAH@N9LNQ.#ECIL.IL.USA.NA ==
=================================================================
Bob Rusk
>Steve, I for one, think this is very sad. Apparently none of us
>convinced you that "18 foot pleasure boats" don't have to weigh
>2000-3000 lbs,
And the corrollary, pleasure doesn't necessarily require an 18+' boat.
>and that lots of pleasure can be gained from boats which
>can be towed by a Honda Accord. I can think of any number of small
>SAILboats, and catamarans especially, that fit this category. Just
>expand your horizons beyond lead-based (keelboats) or iron-based
>(internal combustion engines) technologies, and you'll be surprised at
>how much water-borne pleasure you can have on an Accord-sized budget.
Assuming that the Accord can tow 2000 lbs in your local conditions (which
would need to be flat and not require sustained 65 mph highway speeds),
there are a large number of powerboats that can do most/all of what most
people do with 18' fiberglass I/O runabouts.
First of all, if you can bring yourself to dispense with the I/O, you'll
save 300-400 lbs and still get comparable performance. Your 6-cyl I/O
weighs over 800 lbs and puts out 150-180 hp. This can be replaced with a
300-400 lb outboard that puts out 120-150 for comparable (or better)
performance. I don't want to get into the I/O vs Outboard religious debate
again, but other points in the outboard's favor include fewer moving parts,
no belts and few hoses, no points or distributor, and a better hole shot
(due to less weight in the stern of the boat).
Secondly, lighter weight does not necessarily imply lesser strength or
durability. The Boston Whaler 17 hull weighs 900 lbs, several hundred lbs
less than even a Bayliner of comparable size, yet it is one of the strongest
and most durable hulls around. It's also expensive for its size.
Aluminum hulls are also lightweight and are much less expensive. Many (not
all) are quite durable. My first boat was a 25-year-old Alumacraft. It had
been severely abused through much of its life, but it didn't need its first
hull repair until it was 28 years old.
I just looked at a 1963 Starcraft aluminum boat that is for sale in my area.
It has been overpowered for at least the last 8 years, and had its first
hull repair just 3 years ago. 18-19' aluminum outboard runabouts that will
exceed 40 mph with 115 hp and weigh about 2000 lbs on an aluminum trailer
have been available for years from a variety of manufacturers.
When I was in high school, I bought a 12 year old Starcraft 16' aluminum
bowrider which was powered by an 85 hp outboard (75-80 hp by today's rating
system). The boat seated 6, had a top speed of ~45 mph, would pull a 250 lb
skier up from a deepwater slalom start, and had survived 14 seasons of
teenager-abuse when I sold it, still with no leaks or hull repairs. Oh, and
it weighed < 1500 lbs rigged and on its trailer. Almost any car will tow
that much if you're gentle.
So, even if you aren't willing/anxious to switch to sailing, there _are_
alternatives to purchasing a boat that will require you to own a truck
throughout its lifespan.
--
Bob Rusk
rr...@ssd.csd.harris.com
My thoughts, probably not Harris'.
Paul Kamen
This was the problem:
>A boat with a water propeller and an air propeller properly
>linked together can go directly upwind. But it can also go
>directly downwind, at a speed *greater than the true wind
>speed.*
>
>How is this possible?
>
>Best answer received (in email) before May 5, 1994, 23:59
>GMT will win a free TWILIGHT ZONE team sweatshirt.
>
> -"Call me Fishmeal"-
And here are the answers submitted:
*****1*****
From j...@cs.brown.edu Thu Apr 28 10:35:59 1994
Organization: Brown University Department of Computer Science
The short answer is the "twin iceboat" answer -- the blades of
the iceboat are the (very efficient) water prop and the jibing
sails of the iceboats are the (fairly efficient) air propellor.
Why is this *like* the water boat problem? Because the only
difference is in the constants -- water friction has a larger
coefficient than the ice friction. But to anyone who's ever rowed
a single scull, it's pretty clear that without too much force,
you can make a pair of these move pretty fast. So...in light to
moderate winds (e.g. about 8 kts) you should have no trouble
putting together a craft that does what the twin iceboats do.
The more cryptic answer, is "apparent wind."
Expanded: the apparent wind seen by the jibing iceboat sail is
muchfaster than the true wind. And the apparent wind seen by the
jibing iceboat sail is much larger (and this is the relevant
point) than the apparent wind seen by the "dot in the middle of
the bungee cord tying the two iceboats together".
Notice, by the way, that the iceboat blades, during one of these
downwind rushes, are applying a force to the ice that it
*downwind* i.e, the ice is applying a force to the blades that is
pointed *upwind*. In the water-boat analogy, this means that the
prop is *dragging* and that it's spinning the "windmill". Thus
when the craft is headed downwind at the true wind speed, and the
"apparent wind" to the sailor seems like 0 kts; the windmill is
turning, and therefore able to generate some force to push
downwind even faster.
How'd I do? Not a single equation!
-John
*****2*****
From kin...@dtsdev0.sps.mot.com Thu Apr 28 10:43:44 1994
Organization: Motorola, Inc.
Some possibilities...
a) One Hell of a current.
b) Propellers linked with 454 cu. in. adapter.
c) The air propeller is situated with blades generating lift in
downwind direction. The water propeller is extracting some energy
from the forward movement to turn the air propeller. Beats me if
you could make it efficient enough to actually work, but it would
be the rotary equivalent of what a normal sailboat does in a
linear fashion. In other words, the normal sailboat uses its keel
to convert some of the energy extracted from the wind for driving
the lifting surface (the sail) transversely through the air, in
order to generate additional lift. It's not too hard to imagine
the bottom half of the propellers forming a sailboat (keel and
sail) on one tack, and the top halfs forming a sailboat on the
other tack. The left and right edges are on up and down tacks,
but these are only encountered in the worst of offshore races.
:^)
-dave
*****3*****
From rmci...@mv.us.adobe.com Thu Apr 28 11:09:49 1994
Organization: Adobe Systems Incorporated
Boy, you sound a lot like a professor I had in college. Never
did get the one about the fly on the windshield wiper on a car
accelerating down the road.
Let's see... standard assumptions
Assume no drag from the water against the hull.
Assume frictionless pullys.
The wind would turn the air prop, which would turn the water
prop, which would drive the boat forward.
At exactly true wind speed, apparent wind would be zero, thus no
force to drive the props.
At speeds greater than true wind (assuming you could ever get the
speed to start with), apparent wind would be a head wind.
Reverse the coupling of the props, so that the headwind drives
the boat forward.
Sounds like perpetual motion to me.
*****3a***** [another entry from Rod]
Boat moving through the water drives water prop, which turns air
prop, which propels the boat forward. Wind drives boat directly
up to nearly wind speed. Water prop driving air prop pushes just
a little more.
It still sounds like perpetual motion.
I give up. Let me know the answer on May 5.
Rod McInnis
*****4*****
From ek...@kanga.INS.CWRU.Edu Wed May 4 22:50:25 1994
I dunno know. Maybe a 5 knot wind and a 10 knot current?
I can do it with a series of gibes on broad reaches but
*directly* down-wind has me stumped. E-mail me the the answer in
case I miss it on the postings. I've been scratching my head and
drawing little diagrams for the past hour and a half and I've
*got* to have the answer.
Thanks. Bill
Bill Shatzer - bsha...@ednet1.osl.or.gov
*****5*****
From msol...@mitre.org Thu May 5 06:06:42 1994
Organization: The MITRE Corporation
It's only possible if there is a motor attached to the
propellers.
Moise Solomon
SHOCKWAVE
J/24 #4112
msol...@mitre.org
*****6*****
From ECF_...@JHUVMS.HCF.JHU.EDU Thu May 5 07:56:11 1994
Hmm, does this mean none of the entries you got were any good?
It's just an air propeller (fan?) connected by some gearing,
likely some sort of variable ratio transmission (maybe a
continuously variable one) to a water prop. You could have a
single ratio gearing and it would work, but how could it be
optimum over a range of wind and boat speeds? You have two
beveled gears that transmit power from the horizontal air prop
shaft to a vertical shaft inside the 'mast', so the air prop can
be rotated about the mast to face the apparent wind (I'm not
going to do an ascii diagram so I'll probably lose). Apart from
aerodynamic fairing issues, it doesn't much matter a lot what
direction of motion (that is, forward or reverse) the gearing
finally supplies to the water prop, because you can rotate the
prop 180 to provide the reverse of 0 degrees.
Such a craft should be quite fast straight upwind, you just keep
going faster and faster as your apparent wind builds. I'm
thinking the air props power would be related to the square of
the apparent wind velocity. There would be some point especially
for a displacement boat where the drag of the craft going v+delta
v would be greater than the force generated by the prop system at
w+delta w (w=app wind) and equilibrium would be established. The
fan itself will be generating more and more drag at higher speed,
so there are several practical limits (GODDAMIT I SAID CHANGE TO
THE #2 FAN!). If you get fanciful, you might start thinking of a
perpetual motion machine, you continue to get power from the
apparent wind you are generating, even in no wind. This is true
but obviously the power will be some fraction of that required to
maintain your speed. Anyway I'm betting you should be able to go
upwind at several times the true wind speed.
Ok, how about dead downwind? Well one way to sail is to just go
ddw with the prop 180 opposite the upwind case but this obviously
doesn't work. If you sail a hot jibing angle (apparent wind
behavior is no different than that for a sailboat), you should be
able to fall off to ddw while making faster vmg than the wind,
and then shift to upwind mode. But is there enough energy to keep
you going? what if the wind suddenly dies at this point does that
mean you go faster still (perpetual motion machine revisited)? In
other words, I don't think this can work either.
A way that should work is to have a 'jibing fan' on a track. This
works the same way the guy on water skis uses his jibing kites.
The fan would always be reaching from on side of the deck to the
other. The mechanics of this are a little more complicated, you
would need to switch way the fan is pointing at each 'jibe', but
I can think of several ways this could be accomplished.
If there is another way, hell I can't think of it!
Tom O'Toole
*****7*****
From gr...@vixen.pen.tek.com Thu May 5 09:00:52 1994
Put a motor in the driveline.
Greg
*****8*****
From <@mail.uunet.ca:quasi.ca.geac.com!ross@geac> Thu May 5
11:48:51 1994
Organization: Geac Canada Limited
Easy: True wind 1 knot, 2 knot current same direction, props
locked. Heck, I've done this in my Etchells.
--
Ross Morrissey ro...@geac.com | uunet!geac!ross
*****9*****
From ohl...@fluida.Colorado.EDU Thu May 5 13:38:57 1994
Dear Paul Kamen,
I saw your post about the dual propeller boat. The December 1975
issue of Scientific American has a write-up of a small model-size
version of such a craft. The article is one of the Amateur
Scientist stories. The guys who originally made it and sent in
the information to Sci. Am. are in the School of Oceanography at
the Univ. of Washington.
The working version I saw (working within the past year) is just
under 2 feet long and has a long shaft link between the large air
propeller and the smaller water propeller. This shaft is held
between two catamaran hulls and is at an angle of 20 or so
degrees to the horizontal so that one end is submerged and the
other high enough off the water to support the larger air
propeller.
The craft works nicely into the wind as the water propellor is at
the front and air at the rear, and is more or less stable that
way without any rudder. In answer to your question about
downwind, I don't think that this set-up can go faster than the
true wind since at the true wind speed, there is no apparent wind
for driving. You need some way to get it over that lull so that
there is apparent wind again and then it'll work as before
(driving into the apparent wind) however with much more
water/wave drag than wind drag. I would imagine that a variable
pitch, prop size or gearing would help for these two extremes
(upwind = large apparent wind, lower water speed and downwind =
smaller apparent wind, large water speed).
In any case, the guy to talk to about all this is Eric Lindahl at
the Univ. of Washington. (lin...@killer.ocean.washington.edu -
intermittently). He built the original monohull version and got
it to work in his bathtub. Then Peter Kaufman, also at UW, built
the multihull version that I saw and is written about in Sci. Am.
Finally Seelye Martin (the physical oceanography research
professor who employed these two technicians) gave a write-up to
his buddy the Sci. Am. amateur scientist writer (Stong, I think).
Eric is a VERY clever guy who perhaps deserves your T-shirt if
you weight your responses in terms of priority even though I'm
sure he won't email you. Me, I'm just a lurker on rec.boats who
was a Postdoc at UW until last fall and worked with Eric, Peter,
and Seelye doing laboratory experimental geophysical fluid
dynamics.
Dan Ohlsen...@fluida.colorado.edu
*****10*****
From ma...@watson.ibm.com Thu May 5 15:17:52 1994
So I'm sailing directly downwind, faster than the wind. Thus
theapparent wind is in my face. Now the true wind dies. The
apparent wind thus INCREASES. So I must be able to keep going at
least as fast. In no wind at all. Lets patent it right away!
Marc Auslander <ma...@watson.ibm.com> 914 784-6699 (Tieline
863 Fax x6306)
*****11*****
From dem...@els.cray.com Fri May 6 05:10:59 1994
Organization: Cray Research Inc.
Becuase the boat is in the moving air mass going downwind, and
has an air propeller, it will obtain forward thrust which will be
added to the air speed vector. The resultant vector would be
somewhat larger than without the air propeller.
Larry DeMers
dem...@els.cray.com
*****12*****
From ho...@hpcvcdu.cv.hp.com Wed May 4 13:53:37 1994
Well, wind drive through the air propeller would certainly seem
impractical since drive force would be zero at true wind speed;
so I would have to guess that the water propeller is driven as
the boat's windage causes downwind way and the linkage creates a
"pushing" force from the air propeller. This linkage would have
the same polarity as the upwind one; however, I am not at all
sure what appropriate ratios would be for travel in either
direction.
Unless, of course, you consider current and with sufficient
downwind current, any craft that floats can exceed true wind
speed.
regards, David Hood, ho...@hp-pcd.cv.hp.com
John Donaghey
bed:
I own a 1990 Honda Accord EX and read the owner's manual
on this subject before I went and bought a Yamaha Wave
Raider. The owner's manual states that the boat AND trailer
must not exceed 1000 pounds and that the tongue weight must
not exceed 10% of the total weight (i.e. 100 pounds).
So, obviously, a 2000-3000 boat will be a little much.
Paul Kamen
It came down to four finalists: jfh, kinzer, rmcinnis, and hood.
They all had the first half of the problems solved, recognizing
that the air propeller provides the thrust, propelling the vessel
forward, while the water propeller collects the power, operating
in "underwater windmill" mode.
What nobody explained, though, is why there is enough power
availble to make this work. You need to know that power is
proportional to thrust times velocity. So if, for example, the
boat is going 10 knots dead down in a 5 knot breeze, and the
thrust from the air propeller exactly equals the drag from the
water propeller (and hull drag is 0 and all efficiencies are
100%, for the time being), then the water propeller generates
twice as much power as is required by the air propeller. That's
because it's moving twice as fast through the fluid it operates
in. You can throw in some realistic efficiencies and drag
numbers, and actually come up with a design that would work.
However, to my knowledge it's never actually been done.
So, the winner? rmcinnis, for the shortest explanation that had
the forces going in the right direction. It was a tough call
among the four, though. Send me your snail-mail earth
coordinates, your TWILIGHT ZONE shirt is in the mail.
Bob Niemi
>
>> Has anyone had experiences towing a 2000-3000lb boat with a Honda Accord?
>
>
>>As soon as I pay off the loan on my new truck, I'll be
>>able to buy a boat. See y'all on the water in 5 years! :-(
>
Lots of factors in towing. Can the car frame stand up to the workload imposed?
Have you enough horsepower/torque, alternatively the patience to travel at
10 MPH in low gear? More important than going--cornering and STOPPING
(why is it when they see your rig coming they have to pull out right in
front of you for fear of having to pass you later???---dead is dead!!!)
and emergency handling. Will it pull you out of a launch, or prevent you
sliding back into it (vehicle/tow weight ratio)? How long are the trips?
I would not exceed the weight limits on a Class I hitch, or the manufacturer's
tow rating on that unibody. You may end up with a two piece car.
IMHO, this load is too much for the Accord.
Options include--a special tow vehicle--consider a 1972 Chrysler ($250)
or a 1975-90 Dodge plain farmer truck pickup which need not cost much,
but can take care of your towing problem. If you don't tow often, rent
or borrow. If you want to go boating, you needn't necessarily
pony up for a brand new truck. They don't float (for long) anyway.
Or, trade in the Accord rollerskate for a real tow vehicle ;)
But, find a way--boating is too important to delay for the sake of mere
money....... Good luck!!
Bob Niemi, W9FNJ, Astronautics, Madison, WI niemi%astr...@spool.cs.wisc.edu
John Wexler
fish...@netcom.com (Paul Kamen) writes:
|> What nobody explained, though, is why there is enough power
|> availble to make this work. You need to know that power is
|> proportional to thrust times velocity. So if, for example, the
|> boat is going 10 knots dead down in a 5 knot breeze, and the
|> thrust from the air propeller exactly equals the drag from the
|> water propeller (and hull drag is 0 and all efficiencies are
|> 100%, for the time being), then the water propeller generates
|> twice as much power as is required by the air propeller. That's
|> because it's moving twice as fast through the fluid it operates
|> in.
I like this. It's better than those proofs that 1=2 that puzzle
schoolkids. For the schoolkids, a little algebra is enough to distract
them from spotting the multiplication by zero that makes both sides
equal. Here, we have a mechanical linkage between an air propeller and
a water propeller to hide the flaw. You can apply the same "logic" to
the hull and sail of an ordinary boat, and then the proposition looks a
lot less convincing. Running dead downwind, in a steady state, in still
water, the forces between water and hull must be exactly equal and
opposite to the forces between wind and sail (otherwise the boat would
accelerate). But if you calculate "power" as "force times velocity
through the medium", you get a lower figure for the sail than for the
hull, because the relative velocity of sail through air is less than the
velocity of hull through water. You can then use this "imbalance of
power" to prove that the boat must speed up, slow down, jump out of the
water, spontaneously combust, or teleport to the Bermuda triangle.
Nice one, Paul.
John
P.S. - a couple of weekends ago, I really did sail dead downwind for
about an hour, faster than the wind, in a genuine very low-tech sailing
boat. It was very easy indeed. We made about three miles in that time.
Rick Emerson
RT> Steve Zinski asks :
RT>
RT> > Has anyone had experiences towing a 2000-3000lb boat with a Honda Accor
RT> > I would like to purchase an 18' pleasure boat and tow it with an Accord
RT> > I purchased a Draw-Tite class 1 custom hitch which looks rugged enough
RT> > pull well over its 2000lb rating (a local boat dealer said that he's
RT> > pulled 3000lb boats with a class 1 hitch for years with no problem.)
RT>
RT> And finally decides :
RT>
RT> >As soon as I pay off the loan on my new truck, I'll be
RT> >able to buy a boat. See y'all on the water in 5 years! :-(
RT>
RT> Steve, I for one, think this is very sad. Apparently none of us
RT> convinced you that "18 foot pleasure boats" don't have to weigh
RT> 2000-3000 lbs, and that lots of pleasure can be gained from boats which
RT> can be towed by a Honda Accord. I can think of any number of small
RT> SAILboats, and catamarans especially, that fit this category. Just
RT> expand your horizons beyond lead-based (keelboats) or iron-based
RT> (internal combustion engines) technologies, and you'll be surprised at
RT> how much water-borne pleasure you can have on an Accord-sized budget.
This is a good point!
RT> Instead of solving your problem - how to get on the water with only an
RT> Accord as tow vehicle, we all told you horror stories about towing, and
RT> scared you off the water for another 5 years.
RT>
RT> BTW, I believe the 2000 lb rating for class 1 hitch comes from the
RT> rating of the 1 7/8" ball, not from the hitch itself. I believe if you
RT> use a 2" ball, you get 3000 lb rating, and hitch can take it no
RT> problem, like the dealer said.
RT>
Jim, I hope you're ready to back this up with paying for the repairs
when things go wrong. And they *will!* The Accord is a great car (I
just bought my fourth; the last had 159K on the clock) but it's not
meant to tow beyond its limits. Putting in a stronger hitch, whether
by swapping the ball (which I doubt) or by devising a stroneger mount,
won't overcome inherent limitations in braking, drive train, etc.
Rick
...
* ATP/Linux 1.42 * If you try to be too sharp, you will cut yourself.
Thomas E. Simkins (CCB)
problem is the air, can you explain how the air's momentum is changed to
provide thrust when the boat's velocity is equal to or greater than the air's
and in the same direction? Unless this happens, all the propellers and whirligigs one interposes cannot make it happen. i.e., if in fact, the scenario is
physically possible, there ought to be a simple "explanation" in terms of
a change in momentum of the air.
--
As always, Tom |"It is vain to look for a defense against||
| lightning"-- Publilius Syrus, 45 B.C. |
acss...@eku.acs.eku.edu
> In article <CpwK...@oakhill.sps.mot.com>, rtc...@email.sps.mot.com (Jim
> Casto) wrote:
>
> [some good stuff about maybe choosing a lighter boat instead of a heavier
> tow vehicle, followed by]
>>
>> BTW, I believe the 2000 lb rating for class 1 hitch comes from the
>> rating of the 1 7/8" ball, not from the hitch itself. I believe if you
>> use a 2" ball, you get 3000 lb rating, and hitch can take it no
>> problem, like the dealer said.
>
> While this may be the case with _some_ class 1 hitches (and I'm extremely
> skeptical that it is), it sure isn't the case with all of them. Have you
> ever looked at the attachments of a class 1 hitch? I've seen some where
> the braces attach to the external body sheetmetal. Very weak.
>
> Re your assertion about ball size, I believe a class 1 hitch typically has
> a hole for a "small" shank (can't recall the exact sizes at the moment),
> while class 2 and up have larger holes and take larger shanks. You can get
> both 1-7/8" and 2" balls with either size shank (I've owned all four
> possible combinations at various times). I'm sure the smaller shank size
> has something to do with the class 1 rating, so even if you put a 2" ball
> on a class 1 hitch, it'll still be a small shank, and will still be a class
> 1 hitch rated for no more than 2000 lbs. In my experience, this rating is
This isn't exactly true about shank sizes. The most popular shank sizes
for 1-7/8" and 2.0" hitch balls are 3/4", 1.0". You can get 3/4" shanks
rated at least as high as 3500 pounds. I just saw one in Overton's or
Ski-Limited. It is true that a class one hitch would still be a class
one hitch even if the ball were rated at 30000 pounds. Sometimes the
limiting factor is the coupler itself. 1-7/8" couplers are often rated
less than 2" couplers and I'm sure there is a circular relationship at
work here as well. There's no use rating a ball higher that the coupler
that fits it, and no use rating a coupler higher than the ball that it
fits.
> stamped the hitch draw bar of class 1 hitches. I've never seen one that
> said "unless a 2" ball is used".
Me neither. But I have seen couplers that say 1-7/8" or 2" balls. I
don't know which size they use for the rating of these couplers though.
Or if they list two ratings.
dsc
Dudley Cornman - Systems Programmer
Academic Computing Services
Eastern Ky. University
Richmond, KY 40475-3111
(606) 622-1986
David Knight
Again, you absolutely cannot create a boat or anything else that is
powered by the wind to travel directly down wind at a speed faster than
the wind speed........................................................
It does not matter if you are on water, ice, in the air or some frictionless
matter.
It does not matter even if all of your power conversion is 100% efficient.
The best you can do even in an idealized situation is make the speed
of the wind.
Here is the key to traveling faster than the wind while tacking. While
going directly down wind as you go faster the power generated by the
sail steadily decreases until you reach the speed of the wind at which
time the power is ZERO. There is NOTHING you can do about this!!!!!!!
When you are tacking however you to travel farther (faster) to keep
up with the wind. At a small angle off the wind direction you just have
to go a little faster than the wind before the power goes to zero while
at the extreme if you tack near 90 degrees of the wind direction you
would have to go EXTREMELY fast before the power goes to zero (here
the full power of the sail is likely to be used up trying to overcome
hull resistance)
Dave
John F. Hughes
>
>Again, you absolutely cannot create a boat or anything else that is
>powered by the wind to travel directly down wind at a speed faster than
>the wind speed........................................................
I am willing to publicly bet you, say, $500 that you are wrong about
this. And I'll prove it to you next winter...
It's always a bad idea to make absolute statements when there are known
facts that contradict them. You have to work so damned hard getting the
shoe leather taste out of your mouth. Check out Marchaj's book on
Aero-Hydro-Dynamics of Sailing, and read up on the section about iceboats.
Then you can write your own careful explanation of why your previous
"proof" that this cannot be done is wrong.
-John
Fabbian G. Dufoe, III
>RT> BTW, I believe the 2000 lb rating for class 1 hitch comes from the
>RT> rating of the 1 7/8" ball, not from the hitch itself. I believe if you
>RT> use a 2" ball, you get 3000 lb rating, and hitch can take it no
>RT> problem, like the dealer said.
That isn't correct. There are different classes for hitches and
it won't make your hitch any stronger if you mount a larger ball on it.
--
--Fabbian G. Dufoe, III
350 Ling-A-Mor Terrace South | 27 deg 44.5 min N, 82 deg 38.3 min W
St. Petersburg, FL 33705 | internet: fgd3%ni...@palan.palantir.com
813-823-2350 | uucp: ...palan!deep6!nifty!fgd3
Peter Dowden
> :>>able to buy a boat. See y'all on the water in 5 years! :-(
It's all a load of cobblers! Heck, in New Zealand an Accord is considered
a big car! I used to tow two horses in a double float with a Mazda 1600.
You just drive safely that's all. And that means approaching such
obstacles as traffic lights at a speed at which you can stop safely, you
know, the way people used to do in the days before antilock brakes. Cars
these days have braking-power-to-weight ratios way in excess of previous
years, and much more than most heavy trucks and buses. The only issue
here then is, can you get up the ramp, and will you overheat your
engine/transmission.
But your question should have been, I have a Honda. What boat could I
get?
and I would say, whatever boat you want, sell the Honda and move to the
coast.
Peter
i
|\
|T\
|A \
|R \
| 769\
|__<o_\
^\_______/`~~~~~~~~~~~~~~~~~SADCEPG&Tars4221~~~~~~~~~~~~~~~~~~~~
Jim Casto
rick.e...@dscmail.com (Rick Emerson) writes:
> @SUBJECT:Re: Towing with Honda Accord - NO PROBLEM - PICK THE R N
> RT> Steve Zinski asks :
> RT>
> RT> > Has anyone had experiences towing a 2000-3000lb boat with a Honda Accord
deleted
> RT> And finally decides :
> RT>
> RT> >As soon as I pay off the loan on my new truck, I'll be
> RT> >able to buy a boat. See y'all on the water in 5 years! :-(
> RT>
> RT> Steve, I for one, think this is very sad. Apparently none of us
deleted
> This is a good point!
THANKS!
> RT> BTW, I believe the 2000 lb rating for class 1 hitch comes from the
> RT> rating of the 1 7/8" ball, not from the hitch itself. I believe if you
> RT> use a 2" ball, you get 3000 lb rating, and hitch can take it no
>
> Jim, I hope you're ready to back this up with paying for the repairs
> when things go wrong. And they *will!* The Accord is a great car (I
> just bought my fourth; the last had 159K on the clock) but it's not
> meant to tow beyond its limits. Putting in a stronger hitch, whether
> by swapping the ball (which I doubt) or by devising a stroneger mount,
> won't overcome inherent limitations in braking, drive train, etc.
>
> Rick
I never intended the 2nd comment to be associated with the Honda Accord
problem, sorry if I misled anyone. Just making the point that even a
class 3 hitch doesn't rate its full load, unless you use the right
ball.
Thomas E. Simkins (CCB)
>Why use the reference frame of the air? Consider the air staionary, and
>the water mvoing. The water propeller reduces momentum of the moving
>water, and uses the air propeller to push the boat up-current through
>the still air.
>
OK, let's assume that one can indeed sail directly downwind at a speed
greater than that of the wind. We agree, of course, that the boat's
speed and the wind's speed are measured with respect to the land, regarded
here as stationary. So we have the situation whereby the apparent wind
is directed bow-to-stern, i.e., the boat is traveling into the apparent
wind - the wind indicator is directed forward along the centerline of the
boat. Because of the boat's forward motion thru the water, the water
propeller turns, and in so doing can power the air propeller. This, then,
would be the steady-state scenario, would it not?
Now suppose we decide to go sailing on a beautiful day but arrive at the
dock only to find that it is a perfectly calm day. Nevertheless, I install
the water propeller and the air propeller and we board the craft. I then
ask the dock boy (this is one of those fner clubs) to give us a push to
get us started, which he obligingly does. And were off! The wind
indicator is pointed forward along the boat centerline, the forward
motion of the boat turns the water propeller which in turn supplies
the energy to turn the air propeller which pulls us along.
What am I missing here? I really, really have a lot of respect for those
who claim that sailing downwind faster than the wind can be done, so
I'm not going to say it can't. I will eventually get around to reading
what Marchaj has to say about this, but it's more fun to toy around with
the idea before consulting the experts.
Brian_Smith
: Now suppose we decide to go sailing on a beautiful day but arrive at the
: dock only to find that it is a perfectly calm day. Nevertheless, I install
: the water propeller and the air propeller and we board the craft. I then
: ask the dock boy (this is one of those fner clubs) to give us a push to
: get us started, which he obligingly does. And were off! The wind
: indicator is pointed forward along the boat centerline, the forward
: motion of the boat turns the water propeller which in turn supplies
: the energy to turn the air propeller which pulls us along.
At last!. The Perpetual Motion Machine! (^_^)
B.S!
David Knight
> >what am I missing here?
>
>You're missing the fact that power = thrust x speed.
>
>On the still day, power extracted by the water propeller = power required
>by the air propeller, so there's nothing left over to cover various
>inefficiencies. But if the air is moving downwind, water speed (relative
>to the propellers) is greater than air speed, so there's extra power
>available.
>
> -"Call me Fishmeal"-
I believe that
energy= mass*speed^2 (this is potential energy stored in a moving
mass)
thrust=force (often measured in lbs)
force=mass*acceleration
work=energy
work=force*distance (It took a lot of energy (work) to move that
from here to there)
force=power (say the force generated by one horse, a horsepower)
so power=thrust=force
power=mass*acceleration
Maybe your missing that if you are heading down wind at the speed of
the wind the apparent wind speed is ZERO. Again ZERO wind = ZERO power
Dave
Thomas E. Simkins (CCB)
Uh, if you read my most recent post I recanted these words. I neglected the
key difference: on a calm day the air velocity relative to the water is zero
whereas when the wind is blowing of course it is not. Therefore one cannot
compare events under the two scenarios.
And ... if you read my next post, adding to Fishmeal's recent post, I think I
can convince at least a few non-believers that yes indeed, you can sail faster than the wind straight downwind. Of course you can't do it with a sail that remains in a fixed position.
Thomas E. Simkins (CCB)
>
>You're missing the fact that power = thrust x speed.
>
>On the still day, power extracted by the water propeller = power required
>by the air propeller, so there's nothing left over to cover various
>inefficiencies. But if the air is moving downwind, water speed (relative
>to the propellers) is greater than air speed, so there's extra power
>available.
>
OK Fishmeal, I think I'm up to speed on this problem now and yes, I agree that
you can indeed use the wind to sail downwind (directly downwind!) faster than
the wind. I have cobbed up what I think is the simplest example of how this
might be done - at least conceptually - and which contains all of the re-
prresentative elements of the problem.
First, let us all admit that if we were to somehow sail exactly at the wind
speed and not move our sail, then this is as fast as we would go (I assume
no propellers or non-standard equipment at this point. But if we rapidly
pull back the boom we can once again change the momentum of the air and gain
forward thrust - at least momentarily. But this is cheating, of course, since
we are using human muscle to pull the sail back 'against' the air that is travelling
with us at our speed. So...can we find another way to pull the boom back
which does not make use of human muscle. The answer is yes. Place a sea
anchor in the water with a line attached to the end of the boom which is
initially wung out - say at right angles to the boat centerline. The
drag of the sea anchor (Fishmeal's "water propeller") pulls the boom
and with it the sail (Fishmeal's "air propeller") and we momentarily
gain speed and are momentarily moving faster than the wind. Now when the
boom becomes aligned along the center of the boat, the cycle ends and
we have to quickly (VERY quickly) lower the sail, shove the boom back
outboard, raise the sail and while doing all this, let out slack on the sea anchor line. If by this time we haven't lost the speed we gained, we can repeat the cycle and gain still more.
Of course, the above scenario is quite impractical, but it does show how
the thing works. A more practical arrangement is to provide a constant
drag (a water propeller) that can continually move another sort of sail - an
air propeller.
Well, of course, Fishmeal has supplied the proper mathematics. I hope I
have, for some at least, shown that the act of sailing faster than the wind
downwind is consistent with the laws of physics - though probably impossible
because of limitations of the crew.
I really congratulate Fishmeal for introducing us to this great problem!
I've got one for you - but save it until this one is dead and buried.
Paul Kamen
the water mvoing. The water propeller reduces momentum of the moving
water, and uses the air propeller to push the boat up-current through
the still air.
Joe Ozelis
>
>I believe that
> energy= mass*speed^2 (this is potential energy stored in a moving
>mass)
(I haven't follwed this thread much (certainly not from the beginning), so
I'm not sure what argument is being made, however, I feel obliged to correct
some of these misconceptions...)
This is known as kinetic energy... can be converted to potenitial energy
but the form KE=mv^2/2 only applies to single particle dynamics - it's a
differnet (but analogous) expression for fluids, gases.... groups of particles
require that you use the center of mass velocity, and total system mass...
not counting internal KE (relative motions of groups of particles...water
molecules, etc...)
> thrust=force (often measured in lbs)
> force=mass*acceleration
> work=energy
Not so fast... Work is the *change* in energy of a system (either potential or
kinetic energy)
> work=force*distance (It took a lot of energy (work) to move that
>from here to there)
But it is the integral of the product of two *vector* quantities - the
component of force parallel to the displacement is what counts... you
have to be careful in calculating the work done on/by the system...
especially with fluids -
> force=power (say the force generated by one horse, a horsepower)
No - power is energy/unit time... has units of force*distance/time or
mass*dist^2/time...
>so power=thrust=force
> power=mass*acceleration
>
>Maybe your missing that if you are heading down wind at the speed of
>the wind the apparent wind speed is ZERO. Again ZERO wind = ZERO power
>
> Dave
-- Joe
Dave Kinzer
>Maybe your missing that if you are heading down wind at the speed of
>the wind the apparent wind speed is ZERO. Again ZERO wind = ZERO power
It's a darn shame that we can't get any energy extracted from all that
water that is now flowing by at the wind speed. If we could, then maybe we
could turn the air propeller or somethin'.
-dave
Prime Rat
>It's all a load of cobblers! Heck, in New Zealand an Accord is considered
>a big car! I used to tow two horses in a double float with a Mazda 1600.
>You just drive safely that's all. And that means approaching such
Yeah, well on the boat ramp with all the weight in the stern of the car, front wheel
drive cars generally can go down a ramp with a boat on but can't go
back up, especially at low tide when the ramp might be a bit slimy.
If you've got to have a small car (I wouldn't) get one with rear wheel drive.
/Rat
Paul Kamen
You're missing the fact that power = thrust x speed.
On the still day, power extracted by the water propeller = power required
by the air propeller, so there's nothing left over to cover various
inefficiencies. But if the air is moving downwind, water speed (relative
to the propellers) is greater than air speed, so there's extra power
available.
-"Call me Fishmeal"-
John F. Hughes
>>than the wind straight downwind. Of course you can't do it with a sail that re
>>mains in a fixed position.
>>--
>US AND NOW IT STOP (JUST LIKE OF THE CALM DAY).
This is wrong. The power extracted from the "dragging" prop is powering the
"windmill" sail.
Now you'll say (as you have said before) "but your dragging prop will just
slow the boat down!!!!" (excuse the omission of the capital letters and
the extra few puntuation marks, but I've got the gist of it). And you
know what? You're right. The dragging prop will apply a force that slows
the boat down; and the moving prop will apply a force that speed it up.
And the assertion made by the folks here is that the moving prop will do
more than the dragging one will.
You don't like this fact, but you have yet to show us a conservation-
of-momentum proof that it cannot happen. There's a reason you haven't
given us this proof: there isn't one. How do I know this? I've actually
*seen* one of these wind-prop-water-prop boats, back in about 1976.
>
> DAVE
Watch out folks...he's in ALL CAPS mode. He must *really* know what he's
talking about. I have a feeling that this is going to be settled eventually
by the time honored tradition of settling most sports disputes: by drunken
bar-room brawls.
David-
I repeat myself: put up or shut up. I'm betting $500 that I can build
a boat that will go dead downwind faster than the wind at some steady state
nonzero windspeed. Will you accept the bet? Or are you, perhaps, not
quite *that* certain of your assertions? Shouting them louder won't
help.
-John
John F. Hughes
>
>David-
>
> I repeat myself: put up or shut up. I'm betting $500 that I can build
>a boat that will go dead downwind faster than the wind at some steady state
>nonzero windspeed. Will you accept the bet? Or are you, perhaps, not
>quite *that* certain of your assertions?
I've just gotten email from David pleading that he is not wealthy and that
this should be all fun, so I'll reduce the bet to $10 if he wants. He also
pleads that he's spent too much time posting news and needs to lay off, but
that he will "put together a complete explanation soon." He states that he
still believes that he either does not fully understand the problem or that
he is correct. So I'm going to try to state the facts as clearly as I can:
(1) I can build a device of bounded size whose center of mass will travel
dead downwind on a horizontal sheet of ice at a speed faster than the
wind, with no propulsion except that provided by wind, gravity, friction, and
mechanical linkages for transferring these (i.e., gears, shafts, bearings,
etc.) This "faster than the wind" travel will occur at some particular
nonzero windspeed (and actually over some range of nonzero windspeeds) in
a constant wind.
(2) I can build a device of bounded size whose center of mass will travel
dead downwind on a sheet of (fairly flat) water at a speed faster than
the wind, with no propulsion except that provided by wind, gravity, friction,
and mechanical linkages for transferring these (i.e., gears, shafts,
bearings, etc.) This "faster than the wind" travel will occur at some
particular (small) nonzero windspeed (and actually over some range of
nonzero windspeeds) in a constant wind.
By a "device of bounded size," I mean a device that does not "grow in
size" as it travels. I use the center of mass as a marker of "dead downwind"
because it seems like a reasonable choice.
-John
Dave Kinzer
>
>And why can't we get energy from that water? Turn the air propeller just
I can't believe that I need a smiley on that for you Paul, especially since
I was one of the people who answered the question while in contest form.
The sarcasm was a (probably in vain) attempt to help David *get a clue.*
-dave
David Knight
YOU CAN BUT EVEN UNDER IDEAL CONDITIONS OF ENERGY CONVERSION YOU WOULD
SLOW THE HULL JUST AS MUCH AS YOU SPEED IT UP FOR A NET GAIN IN SPEED
OF ZERO!!!!!!
DAVE
David Knight
>mains in a fixed position.
>--
US AND NOW IT STOP (JUST LIKE OF THE CALM DAY).
DAVE
David Knight
>have, for some at least, shown that the act of sailing faster than the wind
>downwind is consistent with the laws of physics - though probably impossible
>because of limitations of the crew.
WHAT A STRETCH THAT WAS AN ANCHOR TO MAKE YOU GO FASTER NOW WHAT A CONCEPT!
SORRY BUT ANCHORS SLOW YOU DOWN THEY DON'T SPEED YOU UP. AGAIN EVEN
WITH 100% ENERGY TRANSFER NO SPEED WILL BE GAINED. YOU WOULD BE BETTER
OFF GIVING THE CREW HAND HELD FANS BUT THAT CHEATING.
DAVE
Bob Kruger
>Subject: Re: Faster than the Wind
>From: tsim...@pica.army.mil (Thomas E. Simkins (CCB))
>Date: Thu, 26 May 1994 23:48:11 GMT
You haven't accounted for all that kinetic energy used to put the sail up and
down, boom back and forth, etc. Notwithstanding.....
When you shove the boom back you will find that the boat will start to slow
down a bit (conservation of momentum and all). Now you are going a bit slower
than the wind. Then when you repeat the procedure you will speed up a bit,
perhaps a bit faster than the wind, but after you have gone through all this
horse play you will find that your AVERAGE SPEED is NOT greater than the wind,
but that your speed is now oscilatory - faster, slower, faster, slower,....
and you may be getting a bit fatigued from all this lunging about the deck,
perhaps a bit seasick, too - but you will not average a speed greater than
that of the wind.
>outboard, raise the sail and while doing all this, let out slack on the sea anchor line. If by this time we haven't lost the speed we gained, we can repeat the cycle and gain still more.
Bob Kruger
>Subject: Re: Faster than the Wind
>Date: Fri, 27 May 1994 07:24:38 GMT
> >It's a darn shame that we can't get any energy extracted from all that
> water that is now flowing by at wind speed.
>And why can't we get energy from that water? Turn the air propeller just
>fast enough to hold the boat at a water speed equal to wind speed. Apparent
>wind = zero. But the propeller is turning, driven by power from the water
>propeller. The propeller still uses the air to produce force on the boat.
>Why do we need apparent wind speed to make this work? We don't! The power
>comes from the water. Because the water is moving much faster, we can get
>much more power from the water (at the same force) than we need to put
>into the air propeller to balance this force.
So let me get this straight. We take out our frictionless boat and head
dead down wind, and after some time find ourselves traveling at or near the
speed of the wind. As we approach the speed of the wind the forward
propulsive force of the wind drops to ZERO and we're gliding along on our
frictionless bay, in perfect harmony with the forces of nature. You, like all
mankind, are not satisfied with this harmonious balance, and wish to squeeze
just a bit more from the world. So you drop this propellor thing into the
water and what happens? Well the drag from the turning propellor starts to
slow the boat a bit, but as the boat slows the forward propulsive force of the
wind rises a bit above zero until you reach such a reduced speed that the drag
force from the water propellor is just ofset by the forward propulsive force
of the wind. You are again in harmonious balance, but alas, you are going
slower. Why? Because the propulsive force from the wind, which had
oriniginally been entirely transferred entirely to moving your boat forward
is now divided between moving the boat forward AND turning the propellor.
This balance occurs at a boat speed slower than the wind speed. But "ha," you
say, I can harness that propellor's energy by rigging it to the blades of my
Wind Bugger and help move the boat forward again. So you hook up all the
frictionless gearwork and what do you find? Well, you will find that your
speed has indeed picked up, but you are still traveling a bit slower than the
wind speed. Why? Because just turning a propeller (if even in a vacuum)
requires some energy, unless these devices are massless. And if they were,
you'd find that your speed would be equal to that of the wind, but no greater.
The propulsive force of the air propulsion will never be greater than the
drag force produced by the under water propellor. Remember, the propellor is
afixed to your boat!
David Knight
> water that is now flowing by at wind speed.
>
>And why can't we get energy from that water? Turn the air propeller just
IN GETTING THE ENERGY FROM THE WATER YOU WILL SLOW THE BOAT EVEN WITH
100% ENERGY TRANSFER YOU ONLY HAVE ENOUGH ENERGY TO SPEED THE BOAT BACK
UP TO IT ORIGONAL SPEED AND NO FASTER. NO NET GAIN IN SPEED!!
CONSERVATION OF ENERGY!!!!
DAVE K
Mark Armstrong soft
>
>Yeah, well on the boat ramp with all the weight in the stern of the car, front wheel
>drive cars generally can go down a ramp with a boat on but can't go
>back up, especially at low tide when the ramp might be a bit slimy.
>If you've got to have a small car (I wouldn't) get one with rear wheel drive.
>
Reminds me of the person launching the boat here in Rochester, NY. The boat
launch is on the river. The weight of the boat plus the moving current pulled
the car into the water. The car was floating down the river with the boat still
attached. At least it was fresh water...
______________________________________________________________
Mark Armstrong
m...@raster.Kodak.COM
______________________________________________________________
David Knight
> I can't believe that I need a smiley on that for you Paul, especially since
>I was one of the people who answered the question while in contest form.
>The sarcasm was a (probably in vain) attempt to help David *get a clue.*
>
traveling directly downwind using windpower or converted wind power
at a speed greater than the wind is possible, PLEASE SOMEONE HELP THEM
"GET A CLUE" What has been described is a violation of conservation
of energy (can't create or destroy energy).
David K.
Paul Kamen
And why can't we get energy from that water? Turn the air propeller just
fast enough to hold the boat at a water speed equal to wind speed. Apparent
wind = zero. But the propeller is turning, driven by power from the water
propeller. The propeller still uses the air to produce force on the boat.
Why do we need apparent wind speed to make this work? We don't! The power
comes from the water. Because the water is moving much faster, we can get
much more power from the water (at the same force) than we need to put
into the air propeller to balance this force.
-"Call me Fishmeal"-
John Grandfield
with a 6 knot current behind you could make a boat sail faster than the
wind.
--
John Grandfield
GTE Goverment Systems
(508) 880-4326
gfi...@rocky.tntn.gtegsc.com
Matthew Sweet
> Is current a factor in this analysis? Going through the Cape Cod cannel
> with a 6 knot current behind you could make a boat sail faster than the
> wind.
No. The windspeed is measured relative to the water.
Yes. You can do it.
Yes. The vector maths hurts.
The basic argument comes down to considering the water & the air to
be two fluids with a velocity difference between the two.
If you can build a device to move you through apparently stationary
water using the air, why should you not be able to build a device to
move you through apparently stationary air using the water?
The use of the word "sailing" is perhaps unfortunate, as a
propeller/airscrew system is being discussed.
It does work, & thinking about it will make your head hurt.
Matthew
Bill Walker
> In rec.boats, fish...@netcom.com (Paul Kamen) writes:
> > >what am I missing here?
> >
> >You're missing the fact that power = thrust x speed.
[...]
> > -"Call me Fishmeal"-
>
> I believe that
> energy= mass*speed^2 (this is potential energy stored in a moving
> mass)
> thrust=force (often measured in lbs)
> force=mass*acceleration
> work=energy
> work=force*distance (It took a lot of energy (work) to move that
> from here to there)
> force=power (say the force generated by one horse, a horsepower)
> so power=thrust=force
> power=mass*acceleration
[...]
You're almost there, Dave. But force does not equal power. Power is work
per unit time (one horsepower = 550 ft.-lbs./sec, if I recall correctly).
So Paul's "thrust X speed" at least has the right units to be power. But
I'm not clear on which "thrust" and which "power" you'd really use here to
get speed.
----------
Bill Walker - WWa...@qualcomm.com - QUALCOMM, Inc., San Diego, CA USA
"First thing we do, we kill all the lawyers." - Shakespeare
bel...@mscf.med.upenn.edu
What if we decide that we're not going to use windpower, but use
water power instead? The device will transmit some of the power from
water rushing by to moving some air in the same direction as the water
current. Now, if we allow this device to move, it will move away from
the direction of the air it is pushing, i.e. upcurrent with respect to
the water. We don't require that it move fast, but that it _moves_ in
the direction so stated. Now, if in this system, the water were
stationary with respect to earth and the air moving, nothing has
changed except that an observer on shore sees our contraption moving
downwind at faster than the wind.
-Marcus.
bel...@mscf.med.upenn.edu
Everyone, try this at home. I "discovered" this when I was about six.
Take a spool of thread, fishing line, wire, anything of this type with
the flanges on the ends of larger diameter than that of the core around
which the thread (or otherwise) is wound. Unwind about two feet, set the
spool down on a flat, level surface so that it can roll with the 'thread'
unwinding from the underside of the spool. Pull the thread away from the
center of the spool, perpendicular to the spool's axis. What happens?
/~~~~~\
/ /~~~\ \
| | * | |
\ \___/__/____________>>> pulling like this ->
____________\_____/_______________
Assuming the spool didn't just slip on the surface and/or swing to one
side, it *followed* the thread, winding it up, moving faster than your
hand in the direction of your hand. This is not perpetual motion. You
can now imagine doing the same thing with two differently sized, coupled,
concentric gears (pinions) riding on very long racks, with one rack moving
and the other fixed. One gear 'transmits' the motion to the other through
the coupling, and both move in the direction of that of the rack engaging
the smaller gear, faster than the speed of that rack. OK, couple these
gears through some sort of transmission. With the proper choice of ratios
in the transmission, the gears/transmission system can still move towards
the direction of the moving rack, faster. Replace these gears with worm
gears, or 'corkscrews'. Let them slip a little on their racks, maybe have
them riding in two different fluids with some slippage there. Mount the
transmission on something to maintain a course along the fluid-fluid
interface. Keep transmission friction to a minimum (easy) and hydrodynamic
losses to something manageable (not so easy). There you have it: a boat
that travels in the direction of the wind, but faster than the wind. No
laws violated.
-Marcus.
Thomas E. Simkins (CCB)
>In article <CqFos...@pica.army.mil> tsim...@pica.army.mil (Thomas E. Simkins (CCB)) writes:
>>Subject: Re: Faster than the Wind
>>From: tsim...@pica.army.mil (Thomas E. Simkins (CCB))
>
Oh for God's sake.
Thomas E. Simkins (CCB)
Oh Well, I said I only hoped to convince SOME people :-)
Randy Hough
> I repeat myself: put up or shut up. I'm betting $500 that I can build
>a boat that will go dead downwind faster than the wind at some steady state
JFH> (1) I can build a device of bounded size whose center of mass will
JFH> travel dead downwind on a horizontal sheet of ice at a speed faster
JFH>
JFH> (2) I can build a device of bounded size whose center of mass will
JFH> travel dead downwind on a sheet of (fairly flat) water at a speed
JFH> faster than the wind, with no propulsion except that provided by
JFH> wind, gravity, friction, and mechanical linkages for transferring
I won't take $500 but I'll take $50... I bet you can't *build* it.
You might be able to construct it in theory and draw it on paper, but I
have $50 that says you can't *build* it. Since I'm only offering 1/10
of your bet, why not build it at 1/10 scale? Say 36 inches LOA? If
you aren't a model builder, draw the plans and I'll build it for you
(I'll even use my $$$ for the materials). It would be worth $50 plus
time and materials to learn how it works. I will add however, that the
"device" must be able to begin at rest (zero speed through the water).
The "proof" could be a photo of a telltale showing true wind direction,
and a telltale on the device showing that the apparent wind is opposite
to the true wind.
Go ahead, show me.
Send plans (or $50 <g>) to:
Randy Hough
PO Box 3761
Redwood City, CA 94064-3761
... Reality-ometer: [\........] Hmmph! Thought so...
Paul Kamen
>I can't believe that I needed a smiley on that one Paul, especially
>since I was one of the people who answered the question while in
>contest form.
Sorry about that, Dave, it's easy to get people mixed up here (you all
write in exactly the same bright white letters on a blue field).
John Grandfield:
>If you can build a device to move you through the apparently
>stationaly water using air, why should you not be able to build
>a device to move you through apparently stationary air using
>water?
That probably would have won the contest, if you had emailed it in
a couple of weeks ago!
But we're making progress, now that David Knight agrees that the
device with wheels can move itself between too solid surfaces at a
speed faster than the relative motion between the two surfaces.
Would anyone like to fill in the last couple of steps in the proof?
John Wexler
j...@cs.brown.edu (John F. Hughes) writes:
|> >I'm betting $500 that I can build
|> >a boat that will go dead downwind faster than the wind at some steady state
|> >nonzero windspeed. Will you accept the bet? Or are you, perhaps, not
|> >quite *that* certain of your assertions?
and
|> (1) I can build a device of bounded size whose center of mass will travel
|> dead downwind on a horizontal sheet of ice at a speed faster than the
|> wind, with no propulsion except that provided by wind, gravity, friction, and
|> mechanical linkages for transferring these (i.e., gears, shafts, bearings,
|> etc.) This "faster than the wind" travel will occur at some particular
|> nonzero windspeed (and actually over some range of nonzero windspeeds) in
|> a constant wind.
|>
|> (2) I can build a device of bounded size whose center of mass will travel
|> dead downwind on a sheet of (fairly flat) water at a speed faster than
|> the wind, with no propulsion except that provided by wind, gravity, friction,
|> and mechanical linkages for transferring these (i.e., gears, shafts,
|> bearings, etc.) This "faster than the wind" travel will occur at some
|> particular (small) nonzero windspeed (and actually over some range of
|> nonzero windspeeds) in a constant wind.
|>
|> By a "device of bounded size," I mean a device that does not "grow in
|> size" as it travels. I use the center of mass as a marker of "dead downwind"
|> because it seems like a reasonable choice.
I would like to check my understanding that
- in still water or on level ice
- in a steady wind
- the centre of mass of your device(s) will travel directly downwind
(not at an angle to the wind)
- faster than the wind
- in a steady state which can be maintained indefinitely
- with no external source of power other than the ambient wind and water
- with no internal source of power, not even people manipulating sails, oars,
rudder, or whatever
- in contact with only the air and the water (e.g., not touching or
tethered to the bottom)
- with everything measured in the same frame of reference
?
I think you have covered all these points except the "steady state" and
"still water", and "touching only air and water" (which I added since my
last posting, but nobody has ever suggested otherwise, so I don't think
it's a significant change).
I'm quite prepared to believe that you can make something which will go
faster than the wind. I am willing to pay money to see a demonstration
of something that will keep going faster than the wind, dead downwind,
in a straight line and a constant speed, for as long as the external
conditions remain constant (and subject to all those other nit-picking
clauses).
If you want to amend the "still water" condition, I can see
possibilities of extracting wave power. I want to convince myself that
even this will not work, in a steady state, to keep your device
travelling faster than the wind; but I haven't yet "proved" to myself
that it's impossible. Even so, it would be worth a bit of
money to see it demonstrated.
It remains only to agree
(a) your price (I'm offering to pay; I'm not betting, so you don't have
to pay me if you fail to convince me);
(b) how you can give me a convincing demonstration,
since I'm a very long way away; and
(c) how I can pay you (if it becomes
necessary) since I don't have a dollar bank account.
(a) Price: I won't go beyond $100, but I think you should quote a price
related to whatever your Patent Office would charge to send me a copy of
a patent. After all, if this device works, then either somebody will
have patented it already, or you should patent it yourself.
(b) Photographs, videotapes, engineering drawings, a verifiable
statement of the principles involved would all help. But I would really
like statements from trustworthy witnesses. If there is any argument, I
suggest we hold it on rec.boats and accept the judgment of the other
readers who can get to see your demonstration. There are rec.boaters
whom I would trust to give an honest report, even though they say they
don't agree with me about this.
(c) Any suggestions?
John Wexler
Edinburgh
Robert Rayfield
Yes, a sailboat can sail downwind with a vmg (velocity made good)
greater than windspeed if:
a. the boat is allowed to gybe downwind.
b. the boat can sail at a speed greater than twice the
apparent windspeed if the apparent wind angle is 45
degrees.
The chart below illustrates the point. I have assumed a true
windspeed of 5 knots and calculated the boatspeed required, the
apparent wind angle, and windspeed to sail with a vmg of 5 knots.
BOATSPEED REQUIRED TO SAIL AT A VMG OF 5 KNOTS IN 5 KNOTS OF WIND
--------------------------------------------------------------
APPARENT WIND
GYBE ANGLE SPEED ANGLE BOATSPEED
0 0 - 5.0
10 0.9 80 5.1
20 1.7 70 5.3
30 2.5 60 5.8 *
35 2.9 55 6.1 *
40 3.2 50 6.5 *
45 3.536 45 7.071 *
50 3.8 40 7.8 *
55 4.1 35 8.7 *
60 4.3 30 10.0
Note: With a gybe angle between 30 and 60 degrees, the boatspeed
must only be slightly greater than twice the apparent windspeed to
produce a vmg of 5 knots dead downwind.
Iceboats, light cats, and very light monohulls should be able to do this
no-sweat. Maybe even large monohulls can do it.
Robert Rayfield - TS&CC - Toronto - S2STOR
* OLX 2.1 TD * This space for rent.
John F. Hughes
> -=> Quoting John F. Hughes to All <=-
>
> > I repeat myself: put up or shut up. I'm betting $500 that I can build
> >a boat that will go dead downwind faster than the wind at some steady state
>
> JFH> (1) I can build a device of bounded size whose center of mass will
> JFH> travel dead downwind on a horizontal sheet of ice at a speed faster
> JFH>
> JFH> (2) I can build a device of bounded size whose center of mass will
> JFH> travel dead downwind on a sheet of (fairly flat) water at a speed
> JFH> faster than the wind, with no propulsion except that provided by
> JFH> wind, gravity, friction, and mechanical linkages for transferring
>
> I won't take $500 but I'll take $50... I bet you can't *build* it.
> You might be able to construct it in theory and draw it on paper, but I
> have $50 that says you can't *build* it. Since I'm only offering 1/10
> of your bet, why not build it at 1/10 scale?
I was planning on building a small boat (like 24") anyhow. For $50,
I'll build a boat that goes DW faster than 1/10 of the wind speed :-).
Remember, I'm the guy with the new daughter. I've got lots better ways
to spend my time than earning $50 for several hours of screwing around
with trial propellers, or even drawing plans... The best way to spend
my time right now is sleep...
-John
Brian Suggs
>IN GETTING THE ENERGY FROM THE WATER YOU WILL SLOW THE BOAT EVEN WITH
>100% ENERGY TRANSFER YOU ONLY HAVE ENOUGH ENERGY TO SPEED THE BOAT BACK
>UP TO IT ORIGONAL SPEED AND NO FASTER. NO NET GAIN IN SPEED!!
>
>
>CONSERVATION OF ENERGY!!!!
>
>
> DAVE K
Conservation of energy, indeed! In your scenario, (with 100% efficient energy
transfer, i.e. no energy going into heat from friction) we have stuck a
propeller in the water, pulling some of the water with us, and we are now
turning the air propeller, pushing some of the air behind us. This decreases
the relative motion of the air and water (which is where all the energy is in
our example). Tell me, where did this energy go?
Ok, now for part 2 of the quiz. Can you use wind power to go forward directly
head to wind? (Hint, reverse the roles of the air and the water and it's the
same problem.)
-Brian
Finn Stafsnes
I am wondering how long I have to wait before someone claim that it is
impossible to sail up-WIND through still water. But I guess most people
believe it is possble because we have seen it or even done it. :-)
Everybody agree that it is possible to drift along close to wind speed
provided the air-foil is big and providing a lot of drag compared to a
small drag through the water.
In such a situation we can choose to look at it as if we are lying in still
air, watching the water flowing by.
If we call the air-foil: 'keel', and the foil in the water: 'sail', then
it should be possible to extract some power from the mowing water and
start sailing up-WATER.
Now, changing back to the the original view on what is moving and what is
stationary, we are moving downwind at a speed greater than the wind.
My imaginatory boat would have to tack downwind if it should go directly
downwind. By using rotating foils in air and water both foils would actually
do the tacking all the time.
I cant see that any magic is needed to do the trick.
--
Finn S
Robert Rayfield
JW>(a) Price: I won't go beyond $100, but I think you should quote a price
John,
A knotmeter costs many times $100. If you want a demonstration of
something with a vmg greater than windspeed, you should put up at least
$5,000.
Just my $0.02 worth...
Robert Rayfield - TS&CC - Toronto
* OLX 2.1 TD * What is a tagline for, anyway?
John Wexler
Robert....@f7064.n153.z1.ship.net (Robert Rayfield) writes:
|> A knotmeter costs many times $100. If you want a demonstration of
|> something with a vmg greater than windspeed, you should put up at least
|> $5,000.
I only want to SEE it and know how it works. I'm not expecting to BUY
it. Now, if it does work, then it would be worth somebody's $5,000 to
buy the device with the IPR, but unfortunately I don't have $5,000 spare
to invest. Assuming, that is, that nobody else has already established
a claim on the IPR by taking out a patent. And that in turn makes me
wonder: if the thing works, and has been demonstrated, and is described
in an MIT report, then has it been patented, and, if not, why not? If
it HAS been patented, then I suppose I have only to pay the Patent
Office some reasonable sum to have them send me a copy, and then I
wouldn't need to pay $100, or $500, or $5,000, for a demonstration from
anybody else.
John
Brian_Smith
: In article <2s2oav$l...@hplvec.lvld.hp.com> bsm...@lvld.hp.com (Brian_Smith) writes:
: >Thomas E. Simkins (CCB) (tsim...@pica.army.mil) wrote:
: >
: >
: >: Now suppose we decide to go sailing on a beautiful day but arrive at the
: >: dock only to find that it is a perfectly calm day. Nevertheless, I install
: >: the water propeller and the air propeller and we board the craft. I then
: >: ask the dock boy (this is one of those fner clubs) to give us a push to
: >: get us started, which he obligingly does. And were off! The wind
: >: indicator is pointed forward along the boat centerline, the forward
: >: motion of the boat turns the water propeller which in turn supplies
: >: the energy to turn the air propeller which pulls us along.
: >
: >At last!. The Perpetual Motion Machine! (^_^)
: >B.S!
: Uh, if you read my most recent post I recanted these words. I neglected the
So you did. But I wrote that based on the pre-recanted posting. In addition,
I added the smiley face to indicate that it was just a facetious comment and
not one that should be taken seriously. I know there are many people on the
network who claim that they do not accept the validity of smileys and the words
say it all. My opinion of that attitude would not, in general, be considered
to be high.
: And ... if you read my next post, adding to Fishmeal's recent post, I think I
: can convince at least a few non-believers
Well you will probably never be able to convince me because I do not have
the necessary knowledge to understand much of the discussions on the subject,
never mind making any real contributions. Even if you built such a machine
and demonstrated it to me, I still would probably believe that you had some
kind of a trick going--like a nuclear submarine towing the thing from
under water. Maybe I'd believe it if Fishmeal told me it was so....
Ah the satisfaction and joys of a closed mind.
B.S!
Thomas E. Simkins (CCB)
This makes itlook as if it was written by Fishmeal - foul play!
John F. Hughes
>
>I think there is a good deal of generalization here on what constitutes
>"sailing". Perhaps it ought to be admitted that a conventional sailboat,
>travelling with a sail which does not move relative to the boat, cannot
>travel dead downwind faster than the wind.
Sure. And a conventional sailboat with only "squaresails" cannot make
much way to windward, and a conventional sailboat with a wood hull and
Lloyds-acceptable scantlings and traditional fasteners can't plane (probably),
and a conventional sailboat can only have one hull, and a conventional
sailboat has to have a cloth sail, not a wing...
You can make up rules to say what you mean by "conventional" and rule
out any new innovation.
>But if what we mean
>by "sailing" is harnessing the energy of the wind by whatever devices
> - as long as they do not supply energy themselves -
Throughout, I have been arguing against a particular claim of D. Knight's,
namely:
>Sorry but you may not go faster than the wind if heading directly down
>wind. Propellors, 100% energy transfer, frictionless hulls, you name
>it and it won,t help. This should not be a difficult concept, the power
>source gradually decreases to zero as you approach the speed of the
>wind and at this point there is nothing left to make you go ANY faster.
I think that this claim leaves the definition of "sailing" pretty wide-open.
-John
Randy Hough
> You might be able to construct it in theory and draw it on
paper, but I
> have $50 that says you can't *build* it. Since I'm only
offering 1/10
> of your bet, why not build it at 1/10 scale?
JFH> I was planning on building a small boat (like 24") anyhow. For
JFH> $50, I'll build a boat that goes DW faster than 1/10 of the
JFH> wind speed :-).
hehehehe...
JFH> Remember, I'm the guy with the new daughter. I've got lots better
JFH> ways to spend my time than earning $50 for several hours of
JFH> screwing around with trial propellers, or even drawing
JFH> plans... The best way to spend my time right now is sleep...
I'm just trying to learn how the contraption works. Your $500 bet comes
across like a bluff <G>. It looks like several people are interested in
calling you on it. I'll chuck in $50, I'll also head the co-op to hold the
$30-$50 from others. Since you will probably spend more than $500 building a
24' "faster than the wind" vehicle, it looks like a net loss of more than
sleep <g>. My offer to build it at my expense at 36" and pay you $50 on top
if it works, seems like a gentlemanly way to settle the issue (at least that
was my intention).
I'm headed of to the library to get the aero/hydro-dynamics book, so I may be
able to answer the question for myself.
Thomas E. Simkins (CCB)
>>Well, of course, Fishmeal has supplied the proper mathematics. I hope I
>>have, for some at least, shown that the act of sailing faster than the wind
>>downwind is consistent with the laws of physics - though probably impossible
>>because of limitations of the crew.
>
>WHAT A STRETCH THAT WAS AN ANCHOR TO MAKE YOU GO FASTER NOW WHAT A CONCEPT!
>SORRY BUT ANCHORS SLOW YOU DOWN THEY DON'T SPEED YOU UP. AGAIN EVEN
>WITH 100% ENERGY TRANSFER NO SPEED WILL BE GAINED. YOU WOULD BE BETTER
>OFF GIVING THE CREW HAND HELD FANS BUT THAT CHEATING.
>
> DAVE
I'm never sure which Dave I'm looking at until I read what he's said. Let's
call them Dave Right and Dave Wrong. I'm sure this post was from Dave
Wrong.
Thomas E. Simkins (CCB)
>In article <1994May27.1...@cs.brown.edu> j...@cs.brown.edu (John F. Hughes) writes:
>>
>>David-
>>
>> I repeat myself: put up or shut up. I'm betting $500 that I can build
>>a boat that will go dead downwind faster than the wind at some steady state
>>quite *that* certain of your assertions?
>
>this should be all fun, so I'll reduce the bet to $10 if he wants. He also
>pleads that he's spent too much time posting news and needs to lay off, but
>that he will "put together a complete explanation soon." He states that he
>still believes that he either does not fully understand the problem or that
>he is correct. So I'm going to try to state the facts as clearly as I can:
>
> (1) I can build a device of bounded size whose center of mass will travel
> dead downwind on a horizontal sheet of ice at a speed faster than the
> wind, with no propulsion except that provided by wind, gravity, friction, and
> mechanical linkages for transferring these (i.e., gears, shafts, bearings,
> etc.) This "faster than the wind" travel will occur at some particular
> nonzero windspeed (and actually over some range of nonzero windspeeds) in
> a constant wind.
>
>-John
......etc.
I think there is a good deal of generalization here on what constitutes
"sailing". Perhaps it ought to be admitted that a conventional sailboat,
travelling with a sail which does not move relative to the boat, cannot
travel dead downwind faster than the wind. If this is what we mean by
"sailing" , then in fact it simply can't be done. But if what we mean
by "sailing" is harnessing the energy of the wind by whatever devices
- as long as they do not supply energy themselves - (such as propellers,
or sails moving due to forces supplied by the motion of the boat thru
the water) then "sailing" dead downwind faster than the wind can most
certainly be done.
Thomas E. Simkins (CCB)
This is by far the best non-mathematical argument thus far (my opinion of course, but who else's counts anyway). Now, can we get rid of the propellers using
this point of view? How about an underwater sail?
Thomas E. Simkins (CCB)
>In article <Cqqn0...@pica.army.mil> tsim...@pica.army.mil (Thomas E. Simkins (CCB)) writes:
>>
>>I think there is a good deal of generalization here on what constitutes
>>"sailing". Perhaps it ought to be admitted that a conventional sailboat,
>>travelling with a sail which does not move relative to the boat, cannot
>>travel dead downwind faster than the wind.
>
>Sure. And a conventional sailboat with only "squaresails" cannot make
>much way to windward, and a conventional sailboat with a wood hull and
>Lloyds-acceptable scantlings and traditional fasteners can't plane (probably),
>and a conventional sailboat can only have one hull, and a conventional
>sailboat has to have a cloth sail, not a wing...
>
>You can make up rules to say what you mean by "conventional" and rule
>out any new innovation.
:-( My purpose in the post (>> above) was to eliminate the ruse nature of
the problem that causes many to think in terms of conventional sailing - you
know, sails set, no unusual devices such as propellers on sailboat, etc.
I think some persons have taken an early position on the argument because
they have assumed such a convention and then, perhaps out of pride, tried
to defend their position even when the 'props' are brought out ( or the
moving sails, kites, or whatever). The problem has scientific merit
in and by itself - in all fairness one should state at the onset that we
are not necessarily talking about conventional sailing. That's all I
meant - really.