What is your fuel consumption?
Matt Lang
I am thinking about getting a harbercraft jetboat ... these things are
made from aluminum and have the 175 HP Mercury sportjet..
So far so good ... Now what raises the fuel warning flag are the
terms:
- jet
- 2 stroke
- carburator (two of them ;)
The boat will burn about 5 gallons per hour at 30 mph... now I was
wondering how this compares to a similar sized fiberglass hboat with
115-150 HP 4 Stroke outboard..
What is the fuel you burn at cruise speed and WOT, whats your boat
size/weight and what motor are you running ..
I am interested in how the relatively light alu jetboat compares to a
more conventional boat with 4 stroke motor..
Any info is appreciated :)
Matt
Calif Bill
throttle opening. Mostly WOT. You might also look at the Willy boats
Predator. It is also a Sportjet powered boat. I have heard that the
Harbercraft's are not as good as the former Jetcraft's (they bought jetcraft
and moved it to BC). Call Willy boats and ask them. Mine is a 1991 Kodiak
pump, but I understand the newer Hamilton's are about 95% of a prop boat
now.
Bill
"Matt Lang" <web...@shaw.ca> wrote in message
news:a0e12e54.04051...@posting.google.com...
DSK
> I run a Jetcraft 21' Bluewater and get about 1.75-2 mpg depending on
> throttle opening.
Dang, we measure fuel in gallons per hour (1.75 on our last trip). Of
course, we burn diesel and only go about 8 knots.
Speed costs!
Fair Skies
Doug King
Gary Warner
> now I was
> wondering how this compares to a similar sized fiberglass hboat with
> 115-150 HP 4 Stroke outboard..
>
I don't know about 4 strokes but I believe there was a rule of thumb
that said for 2 stroke outboards they would burn about 10% of
their rated horsepower at WOT. So a 115 HP would burn
somewhere around 11 gallons per hour @ WOT.
Though I may be wrong....
Stanley Barthfarkle
18.5' fiberglass 'modified V' hull
19.5' Length over all
2200 lbs dry weight
1985 Volvo Penta AQ125B 4 cyl 105 hp 4 stroke
1 barrel Solex carb 35 mm
Volvo Penta 270 Stern drive
14 X 19 modified SS 3-blade prop (14 X 21 effective)
StingRay Hydrofoil
35 mph WOT @ 4800 RPM
32 mph cruise @ 4400 RPM
Premium unleaded fuel (92 octane)
4 adults & 1 dog, ski equipment, coolers, etc-
6-7 gph WOT
5 gph cruise
"Matt Lang" <web...@shaw.ca> wrote in message
news:a0e12e54.04051...@posting.google.com...
trainfan1
> 1985 Bayliner 1952 cuddy
> 18.5' fiberglass 'modified V' hull
> 19.5' Length over all
> 2200 lbs dry weight
> 1985 Volvo Penta AQ125B 4 cyl 105 hp 4 stroke
> 1 barrel Solex carb 35 mm
> Volvo Penta 270 Stern drive
> 14 X 19 modified SS 3-blade prop (14 X 21 effective)
> StingRay Hydrofoil
> 35 mph WOT @ 4800 RPM
> 32 mph cruise @ 4400 RPM
>
> Premium unleaded fuel (92 octane)
> 4 adults & 1 dog, ski equipment, coolers, etc-
> 6-7 gph WOT
> 5 gph cruise
>
>
>
5 MPG at WOT ! Wow, there are some RV owners that would like to do that
well at any speed...
Rob
Bob
have a newly rebuilt AQ130C ( 4 cyl. 130 hp) and it only takes my boat
up to 31 mph at WOT, about 5000 rpm with two adults in it. My boat is
a 17' fiberglass v-hull and weighs about 2000 lbs I would guess, and
has a Volvo 270 outdrive on it.
BTW, it consumes just 3-4 gph at cruise speed (4200 rpm, 27 mph).
Bob
Stanley Barthfarkle <sba...@yahoo.con> wrote:
:1985 Bayliner 1952 cuddy
:
:
Calif Bill
"DSK" <d...@dontbotherme.com> wrote in message
news:3Arqc.3791$UH....@bignews2.bellsouth.net...
Speed is addictive. Why I drove a Corvette when I raced sports cars.
Harry Krause
2003 Parker 2520XL
Yamaha 225 four stroke
About 32' overall (pulpit and transom bracket)
About 6500 pounds with engine, half tank of fuel, stuff
39+ mph at 6000 rpm, WOT 20 gph
24-25 mph at 4100-4300 rpm, 10 gph
Because of the incessant hard chop on Chesapeake Bay, I usually run at
20-22 knots, keeping gph under 10. I watch the fuel flow meter more than
anything else.
Stanley Barthfarkle
one. Boat planes better, and it allows use of a higher pitched prop (14 X 21
SS cupped in my case). Less cavitation, and no "rooster tail"- energy that
would have been wasted with a rooster tail is sent rearward, increasing
propulsion.
"Bob" <am_...@REMOVepanixThis.com> wrote in message
news:c8dm7b$qk1$1...@reader2.panix.com...
Stanley Barthfarkle
actually 105 hp effective. I'll wager that other Volvo engines are similarly
mis-labeled.
"Bob" <am_...@REMOVepanixThis.com> wrote in message
news:c8dm7b$qk1$1...@reader2.panix.com...
Stanley Barthfarkle
> 5 MPG at WOT ! Wow, there are some RV owners that would like to do that
> well at any speed...
This is an educated guess- could be inaccurate, but after several outings
and refilling at the same gas station to a full tank after every outing, it
seems to be about right. I'm using the Hour meter on my electronic compass,
since the engine doesn't have one. The stated GPH rating for this
boat/engine/outdrive/prop combo is a little over 7 GPH at WOT, mine may be
better because I dont reach the 5100 RPM max engine speed due to my
over-pitched prop. Also, the StingRay hydrofoil supposedly improves fuel
economy 10% to 50%.
We skied/tubed for about 2.5 hours Sunday, and puttered around for about 2
more, on a calm lake, and burned less than 14 gallons. 3 adults and 1 dog
plus equipment. I'm not complaining at all...:)
Bob
boat well because my WOT is about 5200 rpm, but than again I don't know
much about props. I do have a Sting Ray hydrofoil but I prefer not to
use it unless I am going to be carrying a large load...it surely helps
me get up on plane faster, but it also reduces my top end by a few mph
as well as making the steering feel "tight" and not as responsive as
without it. One thing that is different on my boat than many of the
newer boats, is that the bow is closed so I can't put passengers up
there, which probably does not affect the top speed, but sure does
impact the ability to plane quickly when the boat has more than a few
adults in it.
Stanley Barthfarkle <sba...@yahoo.con> wrote:
: What prop are you using? Do you have a Sting Ray Hydrofoil? If not, get
:> :
:>
:>
:
:
Stanley Barthfarkle
that you should be able to swing a more aggressively pitched prop (more
top-end speed) with that engine, but it would help to know your outdrive
specs.
"Bob" <am_...@REMOVepanixThis.com> wrote in message
news:c8earl$507$1...@reader2.panix.com...
Bob
(1972) and using the same pitch prop, the top-end was always 31-32 mph,
so I feel good that I can get there with a rebuilt engine. Will a
higher pitched prop, say a 14x19, drop the WOT rpms? If so, how does
that equate to a higher WOT speed? Seems like it would do the opposite,
but like I say I don't know much about props.
Stanley Barthfarkle <sba...@yahoo.con> wrote:
:Bob, what model is your outdrive? Do you know the gear ratio? Seems to me
:> :>
:> :
:> :
:>
:>
:
:
trainfan1
There is one Volvo AQ131A-powered Glastron on our lake that is really
good on gas too (and quiet!). I just didn't realize they were THAT good!
Rob
Stanley Barthfarkle
5100 rpm.
Your theoretical top speed with a 14 x 19 prop is 34.1 mph at 4800 rpm.
Your theoretical top speed with a 14 x 21 prop is 35.8 mph at 4550 rpm.
Prop info: (note- 15% is the average amount of prop "slip")
http://powerboat.about.com/cs/propellers/a/propellingfacts.htm
http://www.a1discountprop.com/propinfo.htm
http://www.rbbi.com/folders/prop/propcalc.htm
http://www.csgnetwork.com/marinepropcalc.html
http://www.go-fast.com/Prop_Slip_Calculator.htm
http://www.fishweb.com/recreation/boating/tips/props/props1.html
"Bob" <am_...@REMOVepanixThis.com> wrote in message
news:c8ec1k$5co$1...@reader2.panix.com...
Bob
Great info, Stanley...thanks. I had *absolutely* no clue that I could
potentially increase the speed by using a higher pitch prop. My
impression was always that your prop should allow your engine to get to
it's max rpm in order to get max speed (which mine does)...guess I was
wrong. But still, I'm not sure I want to spend ~$200 for a new prop to
gain a few mph.
Stanley Barthfarkle <sba...@yahoo.con> wrote:
:Your theoretical top speed with your current configuration is 32.5 mph at
:> :> :
:> :>
:> :>
:> :
:> :
:>
:>
:
:
gehya...@earthlink.net
engines on the ChrisCraft which I haven't even had running to get any idea
of what RPM's should be on it... Wondering what difference there could be
with props and such...
Will get the ratio, gearbox info when I get back to the shop tonight...
Perhaps someone could help me figure it out.
http://www.wildhorse-webdesign.com/boat
"Bob" <am_...@REMOVepanixThis.com> wrote in message
news:c8ef24$6d1$1...@reader2.panix.com...
Joe
Does anyone actually pay you for your web design services?
gehya...@earthlink.net
wanted to see the boat when I first bought it... Haven't done much with it
since throwing it up.
Needless to say, my own site isn't what I worry about.... I spend too much
time on everyone else's.
"Joe" <J...@privacy.net> wrote in message
news:CHzqc.85796$sK3....@nwrddc03.gnilink.net...
Camilo
Matt: I'm fairly familiar with the Harborcraft hulls, the old Jetcraft
hulls and the sportjet.
First, as someone pointed out, Harbaorcraft bought out Jetcraft - and pretty
much changed all the lines to the Harborcraft hulls, whether they be labeled
Jetcraft or Harborcraft. The new Jetcrafts are really nothing like the old
ones, and they are exactly like the Harborcrafts. Not to say
Harborcraft/jetcraft aren't decent enough hulls - they are very fine hulls.
But, they're not of the Grade A+++, bulletproof build quality of the old
Jetcraft. And you're not paying that kind of money either, probably.
Just mho, of course. AND, this isn't your question anyway!
RE: the Merc 175 carbeurated sportjet. I've spent a lot of time with my
friend's and have gone on a very long trip with him as well as many short
ones. Where are you getting the 5 GPH at 30 mph stat? Product literature
(propaganda) or actual experience? Our experience, with a hull that's a bit
lighter than any Harborcraft hull I've seen is more like 10 GPH at cruising
speed which indeed is around 30mph (with over 40 at wot). About 3 miles
per gallon, rule of thumb. Which, by the way, is excellent mileage for a 2
stroke jet. With a comparable large outboard jet on a boat of any size, one
is lucky to get 2 - 2.5 miles per gallon at that speed/rpms, so we've always
figured the sportjet is a good 30-50% better - and this is measured, not
manufacturer's info.
Your mileage estimation at 5 gph would be 6 mpg, which would be
unbelievable for any jet boat with a large V6 two stroke - and about double
what an inboard Chevy-based jet would get (which are generally considered to
be quite a bit more fuel efficient than any two stroke jet) - which
indicates to me how far fetched it is. My 90s era carbeurated Chevy 5.7 L
inboard jet (on an old Jetcraft, by the way) burned 8-10 gph at cruising
(around 30 mph) speed; anything under 10 gph was considered pretty good for
that speed.
By the way, the info my friend received in the sales brochure for his boat
also said 5 mpg at that speed and it's just not proven to be true.
That said, I really think the Merc sport jet line is a great option for a
jet boat. In my opinion, the Merc. sport jet is BY FAR the most efficient 2
stroke carbeureated jet - far more efficient than a comparably powered
outboard jet. I would assume the 200 hp Optimax is even more efficient. I
like them a lot and wouldn't hesitate to recommend them. I definitely like
them better than any outboard jet option because of the efficiency and a lot
more than any chevy-based jet because they're so much lighter and take up
less interior space.
And don't get me wrong - there's absolutely nothing wrong with the
Harborcraft. It's a fine fairly light weight and good value in a hull.
In other words, even though I disagree with your mileage estimate, this
sounds like a great, good valued rig to me, based on what I've seen of the
hulls and what I know of the motors.
Hope this helps.
Cam
Wayne.B
>I am thinking about getting a harbercraft jetboat ... these things are
>made from aluminum and have the 175 HP Mercury sportjet..
A good rule of thumb for estimating fuel burn is 1 gallon per hour for
every 10 horsepower. Actual horsepower at cruising speed should be
about 50 to 60% of maximum. Using those numbers you get a fuel
consumption of 9 to 10 gph which sounds about right to me.
>
>So far so good ... Now what raises the fuel warning flag are the
>terms:
>
>- jet
>- 2 stroke
>- carburator (two of them ;)
>
>The boat will burn about 5 gallons per hour at 30 mph...
I don't think so, see above.
By way of example I have a 24 ft I/O with a 350 cid Chevy rated at 260
hp. At cruising speed it burns about 13 gallons per hour.
My former Bertram 33 had a pair of 454 cid Chevys rated at 350 hp
each. At cruising speed it burned 35 to 40 gph.
My 15 hp Merc 2 stroke burns about 1 gph.
Wayne.B
>Dang, we measure fuel in gallons per hour (1.75 on our last trip). Of
>course, we burn diesel and only go about 8 knots.
==========================
Doug, what kind of boat/engines?
Greg
>
I have been tracking my fuel for about 200 hours. I am doing a tad over 1 GPH
on a 20' pontoon with a 60 merc 4 stroke but I don't go fast very often. I
cruise at around 3000rpm
basskisser
So you could be slow? There are, and were, many, many sports cars, in
racing trim faster than a 'vette.
DSK
> Doug, what kind of boat/engines?
36' hard chine tugboat with a Ford Lehman 135SP.
http://community.webshots.com/photo/73345252/76569411zLxjAQ
We have a four blade prop which I suspect has a bit too much pitch,
clean & light the engine will not get up to rated RPMs.
http://community.webshots.com/photo/73345252/73346078zEdpFX
1600 rpm (which is a little below recommended cruise) gives us about
7.25 knots average and is relatively quiet & efficient. Other cruises
we've been in more of a hurry and burned 2 ~ 2.2 gph.
Fair Skies
Doug King
Calif Bill
"basskisser" <atl_...@yahoo.com> wrote in message
news:3c74f111.04051...@posting.google.com...
1966. But in racing trim those other cars / sports racers were much more
costly. When the 911B came out, the cost jumped to $30k for a race ready
car. This from the $7k range. I almost bought a Ferrari GTO. They were
available after the Datona race for $5500. Did not buy it, as I figured I
could not afford to replace a ZF trannie. Bad decision. Most collectable
Ferrari. Highest price paid during the 90's boom was $16.5 million. Would
have been are really fantastic ROI.
basskisser
As I said, there were many, many faster sports cars in 66 than a
vette. You didn't even mention McLaren
Calif Bill
Take a reading comprehension course. As I quote"But in racing trim those
other cars / sports racers were much more costly. " A McLaren was a sports
racer. A cobra was $8800 in full race trim from Shelby. A McLaren was
probably in the $40k range. I was working full time and going to college
1/2 time. Could not afford a $40k car. $12-16k a year income was good for
the times, but still did not qualify to run a custom racer. Then you had
Holman -Moody showing up at Laguna Seca with the Ford J cars and 2
semitrucks. One as a hospitality lounge and the other with a full machine
shop. Including turret lathe. Back door covered with different rate sway
bars. Yeh, I could afford to own and run a McLaren or a GT-40. . .
gatt
"Wayne.B" <waynebatr...@hotmail.com> wrote in message
news:v8mma0p3rhm63crtf...@4ax.com...
> On 18 May 2004 08:22:34 -0700, web...@shaw.ca (Matt Lang) wrote:
> >I am thinking about getting a harbercraft jetboat ... these things are
> >made from aluminum and have the 175 HP Mercury sportjet..
>
> A good rule of thumb for estimating fuel burn is 1 gallon per hour for
> every 10 horsepower. Actual horsepower at cruising speed should be
> about 50 to 60% of maximum. Using those numbers you get a fuel
> consumption of 9 to 10 gph which sounds about right to me.
Nasty. The 180 hp Cessna I fly burns 7.5 gallons per hour and cruises at
130 knots.
-c