steel hulls?
ray lunder
some advice on what to look for when buying one? Thanks as always.
hpeer
> Anyone owned a steel hulled sailboat in the 40 foot range and have
> some advice on what to look for when buying one? Thanks as always.
Ray,
Are you looking new or used??
Howard
Thomas, Spring Point Light
"ray lunder" <fsxc...@dyahoo.com> wrote in message
news:g49vs3lu2m7anui69...@4ax.com...
> Anyone owned a steel hulled sailboat in the 40 foot range and have
> some advice on what to look for when buying one? Thanks as always.
The word I'd be worried about :: Rust...
There is a metal [ not sure if it is steel ] sail, yacht, near me in the
boatyard.
There are holes large enough to put your hand through on the bottom of the
hull.
terry
> holes in the hull.
For that size and weight of boat; lots of money! Health and fitness
and a certain amount of strength. Also probably some crew, unless it
is fitted with fairly elaborate gear.
Good luck.
Paul Cassel
> Anyone owned a steel hulled sailboat in the 40 foot range and have
> some advice on what to look for when buying one? Thanks as always.
I've seen some power boats less than 50' which are steel, but not, IIRC,
sailboats. Anyway, I helped in a survey of a steel hulled boat mostly to
learn what there is to learn about them. The surveyor had a great deal
of experience with these. Mostly I learned that if I ever bought one,
I'd insist that the survey be done by a surveyor with specific steel
hull experience.
-paul
Ken Marino
> Anyone owned a steel hulled sailboat in the 40 foot range and have some
> advice on what to look for when buying one? Thanks as always.
My wife and I own a 40' steel hulled sailboat, homebuilt in 1985, that we
bought in 2007. It is the only kind of sailboat we even considered once
we decided to buy. All materials have some problems, be it wood,
fiberglass, steel or cement. The obvious problem with steel is rust. The
obvious advantage is strenght. Do have any boat you are considering
purchase surveyed unless you are very knowledgeable about all aspects of
sailboats. We intend to live on the boat most of our retired life (now)
and wanted a boat we could be confident would not sink if we should
accidently hit a rock or coral reef. Rust is not easy to detect as it
will start on the inside of the boat and work it's way out. You have to
diligently inspect the areas of the boat that are difficult to see, both
before purchase and periodically as long as you own it. THERE SHOULD BE
MANY AREAS IN THE BOAT WHERE YOU CAN GAIN ACCESS TO THE HULL FOR A VISUAL
INSPECTION. My wife has owned 3 previous sailboats, 1 wood and 2
fiberglass and would never own anything but steel now. Feel free to
contact us at our e=mail address if you would like to discuss any other
points or to just start up an ongoing dialogue of mutual experiences
sailing. Ken and Diana kph...@earthlink.net
Gregory Hall
> some advice on what to look for when buying one? Thanks as always.
Why buy one? Just get a good side scan sonar and do a search of the Gulf of
Mexico from zero to 20 miles downwind from where "Red Cloud" was prematurely
abandoned and left to her own devices and was, consequently, lost because of
a frightened, unskilled and unseamanlike captain and crew. If you can't
afford side scan sonar then look for the coffee colored water.
Bwahahahhahahahahhahahahahhahahahahhahhah!
Greg Hall
Steve Lusardi
First I have a real problem with anyone responding to queries when they have
no experience or specific knowledge of the subject and yet it happens all
the time in these use groups. Out of all the responders to your query only
Ken Marino should have responded.
For the benefit of all, steel boats offer the most for the least. The very
best yachts are made from steel. There are many good reasons why that is so.
However, they do have a poor reputation with the uninformed for a few
reasons. The first is that steel boats are virtual stones and cannot get out
of their own way and that can be true IF the boat was built from a design
not specific for steel. The second is that rust is a killer and the risk
cannot be economically mitigated. This is patently untrue. It is a risk, but
very easily prevented and most importantly, very inexpensive to deal with if
it should occur. The last is ugly, yes, they can be, but they don't have to
be. Did you ever see an ugly Super yacht?
Steel boats go away from the inside. Condensation is the killer. Stop
condensation and they will last forever. I had a freind that built a 28'
steel sloop and lived on it as a university student. He had no money and
couldn't afford paint. When he graduated he sold the badly rusted boat, but
the bottom of the boat was still shiney steel. No bottom rust in 4 years in
salt water. The inside of the hull must be sprayed with insulation material.
There are a few materials that work, but not many. The first is polyurethane
foam, another is special cork based materials. All others are suspect and
due dilligence and scrutany is required. Another problem area is teak decks.
I could write a book on that subject alone. The last area to be mindful of
is dissimilar materials, potential electrolysis and the electrical wiring
system. The hull must never be electrically connected to the wiring system
in any capacity, even earth. If any of these situations are discovered
during an initial inspection, a very serious survey should be undertaken.
Hulls that have not violated these very basic rules will outlive you.
Steve
"ray lunder" <fsxc...@dyahoo.com> wrote in message
news:g49vs3lu2m7anui69...@4ax.com...
Paul Cassel
> Ray,
> First I have a real problem with anyone responding to queries when they have
> no experience or specific knowledge of the subject and yet it happens all
> the time in these use groups.
Ignore this fool's post. He clearly has no idea what he's talking about.
Robert Larder
"Paul Cassel" <pcassel...@comremovecast.net> skrev i en meddelelse
news:I8SdnaJDGJGp_E3a...@comcast.com...
Such arrogance- had it occured to you that he might actually know what he`s
talking about?
Clue.... what he says is correct, so what does that make you?
Bob Larder
Steve Lusardi
It isn't arrogance, it's knowledge. I have done this steel boat thing for 30
years. I have spent my money and done my time. I do know what I'm talking
about. How many steel boats have you built?
Steve
<sa...@dog.com> wrote in message
news:f9r0t35jbu3724f5c...@4ax.com...
> On Thu, 6 Mar 2008 22:57:30 +0100, "Robert Larder"
> <farm...@post12.tele.dk>
> Paul Cassel's post couldn't hold a candle to Lusardi's for arrogance.
>
>
hpeer
I have a 33 foot steel boat, a bit small for steel but that's OK with me.
The best advise is to go to the Metal Boat Society and get on their
forum. That site has a number of professional designers and builders
and they are generous with their advice.
The advice about boats rusting from the inside out is true. You can get
to the outside, but not as readily to the inside and that is where the
moisture traps and causes rot. Warmer climes with humidity are worse.
See if you can find out how the inside was treated and if it was done by
someone competent. Interior metal preparation is probably the single
biggest deal in the boat for you will play hell redoing it.
Insulation is a big deal for a couple of reasons. I like the sprayed on
insulation as it seems to protect the underlying steel best.
Proper weep holes that let the water run down into the bilge are also
important. Keep the moisture off the hull.
I have seen some boats where the welding was pretty shabby, especially
if it was done by a home builder who was not up to par. My boat, lucky
me, if very fair by comparison.
I have had my boat three years. It is about 1,200 miles from where I am
so I only go out for 6 weeks in the summer then close her up. Last year
I had someone put a heater in her and when I got to her she was filled
with water almost to the sole. It cause some of the interior coal tar
epoxy to separate from the metal. I spent too much time them sanding and
recoating with two part zinc primer. My knees still hurt. However, the
metal was shiny underneath.
Steel expands something like 16 times its original thickness when it
rusts so you should be able to see rust when it starts. You will need
to get on it right away to control it.
There is disagreement over monel or mild steel. From what I can tell
either will do just fine. The builder needs to be careful of using
dissimilar metals and you need to pay attention to bottom paints. On
the other hand lighting is not much of an issue for you as opposed to
glass boat. You do have to go outside to use the cell phone and the GPS
won't work for beans down below.
Another issue is hard chine or fully developed sections. From what I
can see it makes no difference. Some even say they prefer the hard
chine. I think it is mostly a European vs American preference.
The thing about steel, or even aluminum, boats is that they are Gaud
awful strong. Very hard to hole the boat. A couple of years ago an
older fellow was single handing down from Nova Scotia, got beat up
beating, and called to be taken off. His boat washed up on the beach
back in Nova Scotia. By all reports she was a total wreck, because the
scavengers stripped her, but the hull was still good to go.
I saw a boat in Annapolis that had the port side all dented up and
canned in. Seems that it was an older couple who lived on their boat
for many years. They were motoring out of the harbour to lay on a
mooring happy as clams.
Then again, I saw a boat in NC that was for sale. Inside was fine but
the fore lines were all messed up. At first I thought that the boat had
hit the rocks but by all accounts she hardly ever left the berth. Seems
as though it was just nasty welding. Strong but ugly. What a shame.
Then again, I was helping a guy dock a 40 something glass cat and he
wacked the dock, not hard but firmly. I could see the hull deform and
the gel coat fracture and leave a spider web where he hit. Ouch.
I love my steel boat. Bernard Montisiour went with steel. When his
boat got caught on the hook in a storm it dragged up on the beach. Then
they dragged it off again. Other boats were a total loss. Supposedly
his losses were because of down flooding through an open or damaged
hatch. If its good enough for Montisiour that's pretty good.
Paul Cassel
> Gentlemen,
> It isn't arrogance, it's knowledge. I have done this steel boat thing for 30
> years. I have spent my money and done my time. I do know what I'm talking
> about. How many steel boats have you built?
> Steve
>
Any top posting fool can claim that. I have been building steel hulled
boats, as small ast 12 feet, for 86 years.
jeff
> Steve Lusardi wrote:
>> Gentlemen,
>> It isn't arrogance, it's knowledge. I have done this steel boat thing
>> for 30 years. I have spent my money and done my time. I do know what
>> I'm talking about. How many steel boats have you built?
>> Steve
>>
>
By invoking "top posting" silliness, Paul gives away the fact that he is
really a 15 year old nerd who has never been within 100 miles of the ocean.
Jakob Krutzfeld
But if one is 100% correct then how could they be arrogant?
If you find the message hitting a psychological raw nerve ---> shoot the
messenger!
Jakob
ray lunder
Jim
I never understood the top versus bottom posting controversy.
Even though I post at the bottom, I like top posting better because I
don't need to sift through all the messages to find the latest like you
do if the reply is at the bottom.
My guess is that you just need to call people names.
Marty
>
> I never understood the top versus bottom posting controversy.
>
> Even though I post at the bottom, I like top posting better because I
> don't need to sift through all the messages to find the latest like you
> do if the reply is at the bottom.
Jim, you're not supposed to "sift through all the messages", the poster
is supposed to cut the irrelevant bits and leave only the parts relevant
to his reply. It's like many guidelines/rules; a single rule out of
context may make no sense. Posting rules stem from day's of limited
bandwidth, but also lead to succinctness and clarity.
Cheers
Marty
dougk...@yahoo.com
> > Anyone owned a steel hulled sailboat in the 40 foot range and have
> > some advice on what to look for when buying one?
Yes, of course.
Get hull sonogram when the boat is surveyed. A surveyor who is
knowledgable about steel hulls (and you might consider a commercial/
industrial surveyor, not a yacht surveyor) will know this without
being prompted.
"Steve Lusardi" wrote:
> First I have a real problem with anyone responding to queries when they have
> no experience or specific knowledge of the subject and yet it happens all
> the time in these use groups. Out of all the responders to your query only
> Ken Marino should have responded.
>
So, you know everybody that might be on the internet today or in the
near future? You know all their qualifications and their sailing/
cruising history?
> For the benefit of all, steel boats offer the most for the least.
No they don't. That's absurd.
> .... The last is ugly, yes, they can be, but they don't have to
> be. Did you ever see an ugly Super yacht?
>
Yes, many. Rich people can have just as poor judgement & taste in
yacht aesthetics as anybody else, and they are in position to indulge
their whims more.
However, you're correct that steel yachts don't have to be ugly.
Ranger (along with most of the J-class) was built of steel, and she
was beautiful.
> Steel boats go away from the inside. Condensation is the killer.
Yep
> .... The inside of the hull must be sprayed with insulation material.
> There are a few materials that work, but not many. The first is polyurethane
> foam, another is special cork based materials. All others are suspect and
> due dilligence and scrutany is required.
*all* is suspect, even the proper materials can be installed with (or
age can create) a slight air gap that will quickly form a rust pocket.
> .... Another problem area is teak decks.
Agreed again, but then I have always had heretical opinions of teak
decks since having some real experience sailing on them.
> I could write a book on that subject alone.
No doubt. You've already written at least a chapter.
> .... The last area to be mindful of
> is dissimilar materials, potential electrolysis and the electrical wiring
> system.
Yep.
> Hulls that have not violated these very basic rules will outlive you.
Wrong. Maybe you're thinking of a shorter life span than most of us
would be considering reasonable? Or maybe you're one of those folks
that think the U.S. Navy doesn't know anything about steel hull
construction or maintenance, but I suggest you ask them about what the
useful hull life is. They have more experience than anybody... just
about more than everybody else combined.
Steel hulls, given the right sort of great care, can be as long-lived
as wooden boats. We don't know exactly how long, because there are
examples of wooden boats in the 200+ age range and steel ones in the
100+ age range. However you might consider the amount of expert work
they require to achieve that.
Fresh Breezes- Doug King
Jere Lull
>> "ray lunder" wrote in message
>>> Anyone owned a steel hulled sailboat in the 40 foot range and have
>>> some advice on what to look for when buying one?
>
> Yes, of course.
> Get hull sonogram when the boat is surveyed. A surveyor who is
> knowledgable about steel hulls (and you might consider a commercial/
> industrial surveyor, not a yacht surveyor) will know this without
> being prompted.
Unluckily, I had experience in an industrial setting with this.... He
reported a section of pipe as being full thickness (1/2") about a day
before it blew out. It had to be paper-thin.
Make sure the guy can *find* thin metal!
Another PITA was that all paint had to be removed before the reading
could be made.
I'm not sure a better method wouldn't be to "sound" the hull with a big
hammer, or maybe a small pickaxe.
--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/
Jakob Krutzfeld
dougk...@yahoo.com
> > knowledgable about steel hulls (and you might consider a commercial/
> > industrial surveyor, not a yacht surveyor) will know this without
> > being prompted.
>
Jere Lull wrote:
> Unluckily, I had experience in an industrial setting with this.... He
> reported a section of pipe as being full thickness (1/2") about a day
> before it blew out. It had to be paper-thin.
>
Hmmm... now that you mention it, I've known that to happen too. But
that doesn't invalidate the method.... it's technology, not magic!
> Make sure the guy can *find* thin metal!
>
> Another PITA was that all paint had to be removed before the reading
> could be made.
>
The instruments I'm familiar with will read thru paint, but the paint
has to be bonded and uniform thickness. You have to have a test
section that is known to be sound & up to spec.
> I'm not sure a better method wouldn't be to "sound" the hull with a big
> hammer, or maybe a small pickaxe.
>
Sure. Any place it leaves a dent, you know the hull isn't thick
enough ;)
DSK
Moonshadow
> Anyone owned a steel hulled sailboat in the 40 foot range and have
I have owned one steel sailboat, and will never, ever own a steel boat
again.
The rusting just never stops.
Any injury to or failure of the corrosion protection system must be
repaired immediately and perfectly, or the rusting area will expand
rapidly and sooner or later threaten the structural integrity of the
vessel.
Despite your vigilance, some (or more often many) parts of your steel
boat, generally the most difficult areas to inspect and repair, will be
in the process of turning to rust.
My advice is to look instead for a good quality fiberglass sailboat, and
save yourself a great deal of trouble.
Steve Lusardi
actually have no experience with steel boats. I will not dispute your
experience, it happens far too often, but I must ask what effort you
expended to find expertice with steel hull corrosion? There really are
people out there that know how do deal with rust economically and
effectively. If the other casual readers of this thread think that rust is
such an insurmountable issue for steel boats, they should consider the
plagues of other lower density hull construction methods like fiberglass and
wood with fiber osmosis, rot, the lack of ability to host high load
fasteners and the cost or effectiveness of their repair.
Steve
"Moonshadow" <moons...@nospam.org> wrote in message
news:47d38...@news.chariot.net.au...
Roger Long
anything in the last 2 -3 decades) a well built steel boat can last a long
time and be "reasonable" on maintenance. That means somewhere between a
wooden boat and a fiberglass boat. You do need to be vigilant about paint
damage.
However, a boat that was not painted properly, especially on the inside,
will be virtually impossible to get back to a condition where you are not
living as Ed describes without stripping back to the bare hull,
sandblasting, and starting over with the paint.
If I were building a new metal boat though, I would favor aluminum. The
cost of a good paint system for steel closes the cost gap quite a bit. You
can make a temporary repair in a punctured aluminum hull with a cordless
drill, plywood, and sheet metal screws. The weight saved can go into
ballast or stores. Paint breaks don't need immediate attention. Compass
adjustment is easier. Aluminum is not theoretically as strong but aluminum
boats tend to deform and stay watertight in accidents where steel will
fracture.
--
Roger Long
trawler...@gmail.com
> Anyone owned a steel hulled sailboat in the 40 foot range and have
> some advice on what to look for when buying one? Thanks as always.
I own a steel trawler and there is much to be learned in dealing with
metal boats. The boats of today should have been white blasted
immediately followed by multiple coats of epoxy primer before any
finish coatings and all interior areas have at least 2-3 inches of
high density foam sprayed in before building interiors. Exterior rust
is actually less important than interior rust. Many steel vessels rot
from the inside out. Then there's electrical isolation
techniques.....a whole new topic.
Overall, maintenance is somewhat higher (your labor), but not a bad
trade off in terms of vessel strength. If crossing the pond and you
happen to bang into a semi-submerged cargo container, you may get a
dent in the steel. With fiberglass, you're boat is likely to take the
Davey Jones express to the bottom.
Capt. John
http://www.blueseas.com
Edgar
<trawler...@gmail.com> wrote in message
news:2e909878-81a1-46da...@p25g2000hsf.googlegroups.com...
Steve Lusardi
Gordon
Oh no!!!
Not a top poster, not a bottom poster! It's the dreaded NO poster!
Gordon
Steve Lusardi
You are correct about hull strength. The standing rig on my sloop came from
a 70ft aluminum sloop whose owner decided to convert from a masthead rig to
a fractional rig. The name of the boat was the "Dance II" out of Southampton
in the UK. When the new rig was fitted, the owner set out for Gibraltar for
some chartering. At 0200 in the morning running at 8 knots 200 miles off the
coast of Portugal, the vessel struck a partially submerged shipping
container that holed the aluminum hull. The Dance II was lost, but
fortunately without loss of life. Had the hull been made from steel, there
would have been a very good chance the boat would have survived that
collision.
Roger,
Aluminum is good, but corrosion is actually a much bigger problem than with
steel. Even marine grade 5000 series aluminum is very reactive in salt
water, both electrically and chemically. Addionally, it is very difficult to
get a good paint scheme to adhere properly with aluminum. This is especially
true now that Zinc Chromate primer has been banned almost everywhere.
However, the construction techniques available for both steel and aluminum
support watertight bulkheads, where the existence of those are almost
impossible with low density materials and had they been present in Dance II,
the loss of the vessel would have most likely been prevented.
Steve
<trawler...@gmail.com> wrote in message
news:2e909878-81a1-46da...@p25g2000hsf.googlegroups.com...
Roger Long
>
> Roger,
> Aluminum is good, but corrosion is actually a much bigger problem than
> with steel.
Good point and one I should have mentioned. You need a first class, A1, top
grade, no expense spared electrical system and know how to monitor it
constantly.
If the structure is flexing at all, aluminum will not last as long as steel
but will last as long as most cruisers want to own a boat
I would be happy with either.
--
Roger Long
Jere Lull
> Why not go all the way and zinc spray before the epoxy is put on?
The experience on the Tanzer list's iron keels has been that POR-15 is
far superior when properly applied. Zinc spray sounds like a great
idea, but it's about the least of the solutions that work -- many
coatings don't.
Red
>Overall, maintenance is somewhat higher (your labor), but not a bad
>trade off in terms of vessel strength. If crossing the pond and you
>happen to bang into a semi-submerged cargo container, you may get a
>dent in the steel. With fiberglass, you're boat is likely to take the
>Davey Jones express to the bottom.
I wonder if there isn't a practical way to make the underwater section
of the bow/keel stronger on an existing fiberglass boat stronger/more
impact resistant. Surely someone has figured this out, no?
Red
Gordon
> during layup.
>
>
I have an anchor locker forward that drains thru limbers to the bilge.
To me, the best idea would to be to plug the limber and install a low
platform for the chain. Then add drains to exit low to the waterline.
Put clamshells over the drains situated to keep water out when plunging.
Now you have a backup watertight bulkhead which would hopefully be
further back than any damage.
Just a thought.
Gordon
Red
>>of the bow/keel stronger on an existing fiberglass boat stronger/more
>>impact resistant. Surely someone has figured this out, no?
>>
>>Red
Salty:
>Yes. It's often accomplished by the addition of a layer or two of
>kevlar cloth during layup.
As I understad it, Kevlar is not only difficult to get a good bond with,
its not all that great for collision protection as it is for puncture
protection.
Besides, your answer doesn't address what I was asking - something that
can be applied on an older existing hull. I believe Kevlar would not
bond well enough on old polyester to make this practical anyway. Is this
correct?
red
Jere Lull
> I wonder if there isn't a practical way to make the underwater section
> of the bow/keel stronger on an existing fiberglass boat stronger/more
> impact resistant. Surely someone has figured this out, no?
Our designer made the first 5-7' of our 28' boat an isolated chamber.
We, or an errant hole in the bow, could fill that section up without
much compromising our sailing ability as it's disconnected from the
rest of the boat, buoyancy-wise.
As I review the boat's layup, we could take holes a bit further back
with little problem, though absolute safety would require our being
pretty much upright.
I should review my numbers in view of what I've learned since, but at
one time I calculated that if we got a BIG hole in the middle of the
boat, we'd likely not sink due to the massive isolated chambers in our
bow and stern. We might not float high, but we'd float.
In other words, I believe this problem has been figured out, but not by
assuming that we could make the holes impossible, which I feel highly
improbable, but by ensuring that the boat was properly buoyed when
holed.
Martin Baxter
>
> In other words, I believe this problem has been figured out, but not by
> assuming that we could make the holes impossible, which I feel highly
> improbable, but by ensuring that the boat was properly buoyed when holed.
That's because your boat was designed for Canadian sailing, so some
ice-breaking ability was a requisite.
Cheers
Marty
>
dougk...@yahoo.com
> As I understad it, Kevlar is not only difficult to get a good bond with,
> its not all that great for collision protection as it is for puncture
> protection.
>
"Kevlar" as applied in structural composites (ie boat building) is
cloth made of fibers, same as fibgerglass is cloth made of glass
fibers. No magic here.
BTW it may be interesting to note the structural properties of
fiberglass, some other composites, and steel. It is relatively easy to
build a composite that is as strong as steel. It's also easier to
scale the structural properties to the size of the vessel. This latter
property is why steel doesn't make good small boats.
> Besides, your answer doesn't address what I was asking - something that
> can be applied on an older existing hull. I believe Kevlar would not
> bond well enough on old polyester to make this practical anyway. Is this
> correct?
>
No. Kevlar bonds just fine to existing hulls. I know of several boats
that have had this done. It would be better to apply it to the inside
of the the hull, where impacts put the laminate in tension, rather
than the outside (compression) face. However this is not always
practical, and it certainly helps the impact resistance of
"conventional fiberglass" to have a layer of Kevlar cloth on the
outside. A big problem to beware of is that Kevlar can't be faired...
sanding into the cloth leaves frizzies that will NOT lay down no
matter how much resin or paint you try to cover it with. So any
attempt to armor an older hull should have a thin layer of matt or
finishing cloth sandwiched over the Kevlar.
It would also be a very good idea to add positive flotation.
Fresh Breezes- Doug King
Red
No. Kevlar bonds just fine to existing hulls. I know of several boats
that have had this done. It would be better to apply it to the inside
of the the hull, where impacts put the laminate in tension, rather
than the outside (compression) face. However this is not always
practical, and it certainly helps the impact resistance of
"conventional fiberglass" to have a layer of Kevlar cloth on the
outside. A big problem to beware of is that Kevlar can't be faired...
sanding into the cloth leaves frizzies that will NOT lay down no
matter how much resin or paint you try to cover it with. So any
attempt to armor an older hull should have a thin layer of matt or
finishing cloth sandwiched over the Kevlar.
It would also be a very good idea to add positive flotation.
Fresh Breezes- Doug King
I hear ya on the flotation! :)
The reason I asked is that I read an article somewhere way back on some
boatbuilding site that kevlar wouldn't bond adequately to old poly
resin. I'm curious though, why would it be better for the kevlar to be
on the inside? Wouldn't that make it less effective in a collision due
to the layer being in tension so it wants to seperate? I would have
thought that being on the outside would be better to provide a barrier
to the forced entry. Could you explain further? Thanks
Red
dougk...@yahoo.com
A lot of people seem to think it isn't practical. It would indeed mean
giving up some interior space, but IMHO many production boats could
have positive flotation installed and give up maybe 15~20% of useable
stowage. A lot of space could be used for flotation that is up in
tight angles & inaccessible spots.
> The reason I asked is that I read an article somewhere way back on some
> boatbuilding site that kevlar wouldn't bond adequately to old poly
> resin.
Can't think why that would be. It's just fancy cloth. More would
depend on the surface prep & type of resin.
> .... I'm curious though, why would it be better for the kevlar to be
> on the inside? Wouldn't that make it less effective in a collision due
> to the layer being in tension so it wants to seperate? I would have
> thought that being on the outside would be better to provide a barrier
> to the forced entry. Could you explain further? Thanks
>
I can try. A laminated structure almost always fails in compression...
same as a mast BTW. As force applied increases and the structure
bends, at some point the strength of the bond between layers starts to
fail and the inner face of the bend, the skin that is under
compression, starts to buckle. This is where local tears in the skin
form. After this point failure occurs, the whole thing comes apart
like a zipper until the strain is relieved.
Kevlar is very very strong in tension, and along the tension face or
skin will distribute load over a much wider area than conventional
fiberglass cloth, thus avoiding critical point loading in the opposite
compression face.
OTOH if you're thinking of an object piercing the hull like an ice
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.
Fresh Breezes- Doug King
Red
pick, having the Kevlar layer on the outside might not make much
difference. In any event, having it on the outside is better than
nothing.
Fresh Breezes- Doug King
------
Actually I was just pondering this as there are frequent stories about
the various partially submerged objects such as shipping containers
sinking boats. Since I am getting closer to buying a boat, I wondered if
there wasn't something that could be done to at least reasonably
increase protection from said objects. I realize you aren't going to
make it bullet proof, but any amount of improvement without too much
tradeoff in weight, etc, may be worth it. Peace of mind sort of thing.
Thanks.
Red
tsm...@gmail.com
>... Kevlar bonds just fine to existing hulls. I know of several boats
> that have had this done. It would be better to apply it to the inside
> of the the hull, where impacts put the laminate in tension, rather
Amen. But, having been tangentially involved in a completely
disastrous attempt to bond Kevlar (tm) fabric to PVC foam with epoxy I
strongly advise getting advise from the fabric provider before
bonding. A Method that worked very well with both epoxy and polyester
with stitched glass didn't fly with Kevlar (literally as the structure
was a wing for an ultra-lite). And, yeah, you're right, the stuff
goes all fuzzy if you look at it funny and it kills scissors. Carbon
is less of a pain to work with but you can't use it to armor existing
hulls.
-- Tom.
Richard Casady
wrote:
>Aluminum is not theoretically as strong but aluminum
>boats tend to deform and stay watertight in accidents where steel will
>fracture.
For equal weight Al and steel are equal in strength. Considering
weldability and panal stiffness aluminum is better because it is
thicker. Note that the alloys used for boatbuilding are not the
strongest available in either material. In the case of aluminum, the
usual alloys do not need paint, Every fifty year old al boat I know
has been out in the weather without paint and no sign of corrosion.
Most aluminum commercial boats, for example Alaskan fishing boats are
left unpainted in salt water and don't corrode. My 22 foot cuddy is
bare Al, and I wouldn't consider any other material.
You are correct about the fact that steel will tear in cases where
aluminum will just get a big dent. Think shipping container. 10 000 a
year get washed off the boxboats,
Casady
Gordon
Had a friend that put in many, many thousands of miles with at least
7 round trips between New Zealand and Victoria BC.
In that time he hit one container and one sleeping whale. This was in a
homebuilt 33' steel cutter. Both hits in the South Pacific.
The container left a good dent in the bow and the whale bent the rudder.
I guess what I'm trying to say is the chances of hitting something
large enough to cause serious damage is very slight and then probably
wouldn't be catastropic
G
Bruce in Bangkok
Perhaps the first thing wold be to research the subject to determine
how many fiberglass/steel/aluminum/wooden yachts are sunk annually.
Once the frequency is determined it should be easy to assess the
appropriate action.
as an example, airplanes crash nearly every year but few passengers
carry a parachute as part of their carry-on luggage...
Bruce-in-Bangkok
(correct email address for reply)
Bruce in Bangkok
That is somewhere around 45,000 N.M. so if he hit two objects in that
distance it averages one object every 22,000 miles. How many people
will cruise that distance in their whole life.
dougk...@yahoo.com
> Amen. But, having been tangentially involved in a completely
> disastrous attempt to bond Kevlar (tm) fabric to PVC foam with epoxy I
> strongly advise getting advise from the fabric provider before
> bonding. A Method that worked very well with both epoxy and polyester
> with stitched glass didn't fly with Kevlar (literally as the structure
> was a wing for an ultra-lite).
I wonder why. Incompatible binder in the cloth?
One issue with both carbon fiber & aramids (you're right, Kevlar is a
trademarked brand name) is that the cloth is much lighter than
conventional fiberglass... duh, that's a big reason to use it... but
it also means that the cloth tends to float up out of the resin. The
best way to bond it is to vacuum bag it, or use pre-preg, but it can
be laid up like conventional FG once you know to not pour on more
resin when it looks dry. Or you can use thickening/bonding agents
mixed into the resin, that holds it in place better anyway. I used
peel ply, with no vacuum bagging, over a carbon fiber & Kevlar lay-up
with very good results.
> .... And, yeah, you're right, the stuff
> goes all fuzzy if you look at it funny and it kills scissors. Carbon
> is less of a pain to work with but you can't use it to armor existing
> hulls.
>
It would help add compression srength as an outside layer. I dunno if
it would help with impact resistance. The yield curve for carbon fiber
(also called graphite) is almost straight, the stuff tends to fracture
and people think of it as brittle. Of course, it takes about 10x more
force than steel can withstand, but we're so used to seeing stuff bend
before it breaks that it's counterintuitive that material which
*doesn't bend* and suddenly snaps is really strong. And it also
doesn't lend itself to "soft failure" modes.
DSK
dougk...@yahoo.com
> For equal weight Al and steel are equal in strength.
The "rule of thumb" I recall is that aluminum is half as strong as
steel, and 1/3 the weight of steel.
For equally strong structures, aluminum will be about 25% lighter than
steel.
DSK
dougk...@yahoo.com
> > Had a friend that put in many, many thousands of miles with at least
> >7 round trips between New Zealand and Victoria BC.
> >In that time he hit one container and one sleeping whale. This was in a
> >homebuilt 33' steel cutter. Both hits in the South Pacific.
I wonder what time frame this was? I think shipping losses of
containers is much higher in the late 1990s ~early 2000s although they
say it's tapering off now.
I also wonder what happened to the whale.
> > The container left a good dent in the bow and the whale bent the rudder.
> > I guess what I'm trying to say is the chances of hitting something
> >large enough to cause serious damage is very slight and then probably
> >wouldn't be catastropic
> >
In a steel boat ;)
Bruce in Bangkok wrote:
> That is somewhere around 45,000 N.M. so if he hit two objects in that
> distance it averages one object every 22,000 miles. How many people
> will cruise that distance in their whole life.
>
Lots and lots and lots. Not so many do that many open-sea miles. But
look at the odds another way... if you had a revolver with 1,000
chambers, and "only" one chamber had a live round.... would you spin
the chamber, put it to your head, and pull the trigger? Just for fun?
If the odds are low, but consequences very serious, then it's worth a
little work and study to avoid that BANG. Of course, YMMV
DSK
Bruce in Bangkok
Without researching it I suspect that the number of boats lost to
hitting floating objects is less then the number of aircraft lost
during the same period. Do you carry a parachute when you fly?
Gordon
Edward retired in San Diego and built a wood cat and sailed it all
over the S Pac sans engine.
He returned to San Diego, sold the cat and built the cutter.
He went to New Zealand and then to either Pt Angeles Wa or Victoria BC
or even farther north where he would spend the summer or maybe a year.
Edward left NZ last spring in poor health and was reported overdue in
the summer. His boat was finally found washed up on an atoll.
Edward was a very safety oriented person. High welded water pipe for
rails with no gates and sissy bars around the mast.
It is thought Edward probably walked off the stern if he thought his
time had come. He was that type of person.
So you can figure the time frame from this narrative.
Gordon
BTW Edward was 82 years old.
Wilbur Hubbard
"Bruce in Bangkok" <b*paige*125@g*mail.com> wrote in message
news:2r9ct3dvjtk87s466...@4ax.com...
> That is somewhere around 45,000 N.M. so if he hit two objects in that
> distance it averages one object every 22,000 miles. How many people
> will cruise that distance in their whole life.
Certainly not you, sir! Pretty hard to get that kind of mileage under your
keel sitting at the Bangkok dock.
Wilbur Hubbard
tsm...@gmail.com
> "tsmw...@mail.com" wrote:
> > Amen. But, having been tangentially involved in a completely
> > disastrous attempt to bond Kevlar (tm) fabric to PVC foam with epoxy I
> > strongly advise getting advise from the fabric provider before
>
> I wonder why. Incompatible binder in the cloth?
> One issue with both carbon fiber & aramids (you're right, Kevlar is a
> trademarked brand name) is that the cloth is much lighter than
> conventional fiberglass... duh, that's a big reason to use it... but
Good points. Kevlar has been used with great success. I can only
speculate on the reasons for the failure. I was in the shop where it
happened re-building my dagger boards and the wing was going together
on the other side of a hull of a big cat that was also building. So,
I didn't see every detail. They were building it using Kelsall's KSS
system with Kevlar twill, epoxy and pvc. They bonded one face on a
flat table with a wet lay-up using modest vacuum to clamp it. Then
they cut darts in the pvc, draped the part into mdf formers and hand
laid the inner skin. That's sop for the KSS system and it generally
works quite well. In this case, though, both the hand laid skin and
the bagged skin could be peeled off the pvc (failing at the glue
line). They did it all a second time on the assumption that the
problem was a bad epoxy mix and it failed exactly the same way. Other
parts that came off the same table using pvc from the same batch
before, during and after were fine. I was using the same epoxy to
build my boards and it was also being used in a couple of other
projects around the shop and it was fine. It's possible that they
could have contaminated the pvc skins (boat shops aren't exactly clean
rooms). That's what the guy building the plane though. But both
sides twice? I think that using twill rather than stitched cloth and
bending the parts around very tight molds (the guy wanted to mold
right around the leading edge for some reason) were contributing
factors. But whatever the reason, the epoxy/Kevlar joint was the weak
one and I think that is cause for concern or at least careful testing
when using Kevlar.
>>... Carbon
> > is less of a pain to work with but you can't use it to armor existing
> > hulls.
>
> It would help add compression srength as an outside layer. I dunno if
> it would help with impact resistance. ...
The usual argument against carbon reenforcement is that it is so stiff
that it will fail before the glass takes any load. At which point it
might be more sensible to just do away with the glass. Price and
compatibility wise "S" glass might be a better option than either
Kevlar or carbon. In a crash you want strong but flexible to absorb
energy.
-- Tom.
Roger Long
(Scientific term for "Modulus of Elasticity")
There was a rash of rudder stock failures that had an outer layer of carbon
fiber for stiffness. Turned out the plain fiberglass part of the stock was
plenty strong enough. The carbon fiber provided the required stiffness but
took up the whole load before the fiberglass part bent enough to take any
significant load. The carbon fiber fractured and the result was just like
that scratch you make on a piece of glass when you want to break it easily.
--
Roger Long
Steve Lusardi
construction, so I cannot add anything there, but you need to think through
the whole scenario. Adding protection aganst puncture is only one aspect of
the required protection. Although my hull is steel and it has collision
bulkheads both forward and aft, it also utilises watertight bulkheads as
well, but even that is insufficient. You must consider the flotation
attitude of the hull under flood conditions. If any part of the deck falls
below the water surface, the boat will most likely be lost before the
flooding can be controlled.. So keeping the boat deck parallel to the water
is really important and in my case I have a rather fine entry forward and if
flooding the forward compartment should occur the bow would sink well below
the deck line. Adding adequate fixed flotation removes too much space, so my
solution, for what it is worth, is to place a 2 ton hyperlon lift bag below
the forward cabin sole that can be inflated in an emergency. Hopefully, this
would buy enough time for the pumps and to effect a repair from the outside.
Steve
<tsm...@gmail.com> wrote in message
news:f1d7a35b-51ec-4497...@s8g2000prg.googlegroups.com...
tsm...@gmail.com
>... There was a rash of rudder stock failures that had an outer layer of carbon
> fiber for stiffness. Turned out the plain fiberglass part of the stock was
Funny you should mention that. The guy working just up the bench from
me was building the rudders and stocks for the cat and he had built
carbon/glass stocks which failed exactly as you describe. He was
building the cat's stocks out of S-glass/epoxy around small foam cores
(for forming). He'd also built successful carbon stocks (including
the one on his own boat) but felt strongly that mixing materials in
rudder stocks was a bad idea. He also thought that S-glass stocks
were nearly as good as carbon because carbon had to be over-built to
absorb shock loads that were not a problem for S-glass of the required
stiffness. Carbon that's durable enough ends up being stiffer than
needed. There's still an advantage but not nearly as much as you
would guess just looking at the materials. Adding a bit of spring
into a system that takes sudden loads can reduce the peak forces by a
lot. As you say, the engineering gets complicated. Some materials
suppliers will provide engineering help to builders and designers for
surprisingly reasonable fees (even gratis for small stuff)...
-- Tom.
tsm...@gmail.com
letters in the February "Yachting World".
"A chairman of the Scottish branch of the Institution of Structural
Engineers once famously defined engineering as: 'The art of modeling
materials we do not wholly understand, into shapes we cannot precisely
analyze so as to withstand forces we cannot properly assess, in such a
way that the public has no reason to suspect the extent of our
ignorance.'"
-- Tom.
Bruce in Bangkok
And also difficult sitting there with the yellow rubber duck in the
bathtub.
Roger Long
>
> "A chairman of the Scottish branch of the Institution of Structural
> Engineers once famously defined engineering as: 'The art of modeling
> materials we do not wholly understand, into shapes we cannot precisely
> analyze so as to withstand forces we cannot properly assess, in such a
> way that the public has no reason to suspect the extent of our
> ignorance.'"
>
Wow. I wish I had heard that in time to include that in the Titanic
programs
My quote was, "Any idiot can make things strong enough. Engineering is the
science of making them light enough to be affordable and functional in the
real world. The designers of that ship were under enormous pressure to use
the absolute minimum of steel they could get away with."
An official panel of the Society on Naval Architects and Marine Engineers
recently sponsored a paper intended, I believe, to show that I was
completely wrong so as to preserve their standing as the adults and
professionals since I was getting my own TV show, two in fact. They claim
that the ship broke from the bottom up instead of the top down. This is
primarily based on the same calculations used in designing a new ship.
These calculations do show higher stresses in the bottom than the top. The
hardest thing in engineering is predicting exactly when something will fail.
One of the most revealing things I ever saw was when someone invited me down
to the testing machine at Woods Hole where they were breaking a bunch of
bolts to try and determine the exact load as which they would fail so they
could construct weak links for buoy retrieval. The guy said, "You're an
engineer, look at these results." The breaking loads were all over the
place. This was a bunch of identical bolts out of the same box, built on
the same machine, to close tolerances and presumably from the same
manufacturing batch. This was also back when these things came from the US
instead of China where they could be made of anything the street urchins
bring in from the dump.
A single bolt under tension is about the simplest structure on the planet.
The riveted "Titanic" with all those hand fitted parts, highly variable
steel characteristics, joint strength depended on individual workmanship in
riveting, and great flexibility, was arguably one of the most complex
structures to analyse ever built. These quys trying to arrange for their
"official" paper to come out at the same time as the History Channel show
were basing their case on calculations used at the design stage of a ship to
help proportion the steel sizes in the most effecient way and pointing to a
slight difference in stress to strength ratio as "proof" that this guy who
came from nowhere to appear on TV was wrong. The completely ignored the
visual evidence in the steel debris, survivor testimony, and common sense.
I really got some good laughs out of the whole affair.
--
Roger Long
cavelamb himself
a little off subject, but Roger may appreciate this one...
Aircraft design is 90% educated guesses,
worked out to four decimal places.
Roger Long
"Good engineers understand that the numbers are only a guide to their
judgement. Bad engineers believe them absolutely."
--
Roger Long
cavelamb himself
>
> A single bolt under tension is about the simplest structure on the planet.
> The riveted "Titanic" with all those hand fitted parts, highly variable
> steel characteristics, joint strength depended on individual workmanship in
> riveting, and great flexibility, was arguably one of the most complex
> structures to analyse ever built. These quys trying to arrange for their
> "official" paper to come out at the same time as the History Channel show
> were basing their case on calculations used at the design stage of a ship to
> help proportion the steel sizes in the most effecient way and pointing to a
> slight difference in stress to strength ratio as "proof" that this guy who
> came from nowhere to appear on TV was wrong. The completely ignored the
> visual evidence in the steel debris, survivor testimony, and common sense.
>
> I really got some good laughs out of the whole affair.
>
> --
> Roger Long
>
>
>
Roger,
Since you have studied this incident so long, has anyone ever considered
the effect of the temperature of the water on the fracture strength of
the steel uesd to build the hull?
In his book "Structures: Or Why Things Don't Fall Down", J.E. Gordon
analizes the changes in physical properties that the near freezing water
would have had on the steels of teh day.
Had the metals retained their ductility, the damage may have been
limited to a single bay, and the ship survive.
I couldn't turn up that piece of text on line, but a sample of the book
may be seen at http://books.google.com
http://books.google.com/books?id=oQBumxtdfbsC&dq=structures+or+why+things+%22don+t%22+fall+down
I think you would enjoy it.
Richard Lamb
^1 Structures: Or Why Things Don't Fall Down by J. E. Gordon
J.E. Gordon’s book is a great read.
Gordon strips engineering of its confusing technical terms,
communicating its founding principles in accessible, witty prose.
Amazing factoids and insights for the lay person abound in this book,
alhought the technical details may a bit heavy for some.
Witty - it will change the way you see the world
cavelamb himself
that's a keeper!
Roger Long
> Since you have studied this incident so long, has anyone ever considered
> the effect of the temperature of the water on the fracture strength of
> the steel uesd to build the hull?
Yes, and it certainly had a bearing on the details of the event but not the
big picture. She might have broken at 15 - 16 degrees instead of 10 - 12 if
it had been on a summer day.
>
> In his book "Structures: Or Why Things Don't Fall Down", J.E. Gordon
> analizes the changes in physical properties that the near freezing water
> would have had on the steels of teh day.
Great book. I have read it although quite some time ago.
--
Roger Long
dougk...@yahoo.com
"tsmw...@gmail.com" wrote:
> Forgive me for replying to myself, but I wanted to add this from the
> letters in the February "Yachting World".
>
> "A chairman of the Scottish branch of the Institution of Structural
> Engineers once famously defined engineering as: 'The art of modeling
> materials we do not wholly understand, into shapes we cannot precisely
> analyze so as to withstand forces we cannot properly assess, in such a
> way that the public has no reason to suspect the extent of our
> ignorance.'"
>
cavelamb himself wrote:
> Aircraft design is 90% educated guesses,
> worked out to four decimal places.
"Roger Long" wrote:
> Another quote from the infamous Roger Long"
>
> "Good engineers understand that the numbers are only a guide to their
> judgement. Bad engineers believe them absolutely."
"Roger Long" wrote:
> Wow. I wish I had heard that in time to include that in the Titanic
> programs
>
> My quote was, "Any idiot can make things strong enough. Engineering is the
> science of making them light enough to be affordable and functional in the
> real world. The designers of that ship were under enormous pressure to use
> the absolute minimum of steel they could get away with."
>
Engineering is also different from research. Engineers have to figure
out how to build something with the available standard practices of
the day; or provide a practical & workable innovation to standard
practice. It's very easy to say "why didn't you do it like
this" (pointing to some exotic & extreme method which may not even be
a success at the experimental stage).
> An official panel of the Society on Naval Architects and Marine Engineers
> recently sponsored a paper intended, I believe, to show that I was
> completely wrong so as to preserve their standing as the adults and
> professionals since I was getting my own TV show, two in fact. They claim
> that the ship broke from the bottom up instead of the top down.
That's possible. Further down you say there is a lot of evidence it
didn't happen that way, I'm curious. Wasn't there a RINA paper some
years back on the same subject? Until 1985 the expert opinion was that
the Titanic didn't break in half at all.
I'm also curious if you've ever checked into the newsgroup
"alt.history.ocean-liners.titanic" which is a bit slow these days but
is still a major rivet-counter hangout.
DSK
Roger Long
>
> I'm also curious if you've ever checked into the newsgroup
> "alt.history.ocean-liners.titanic" which is a bit slow these days but
> is still a major rivet-counter hangout.
>
rate at which checks for my work on the subject are flowing. I got a ride
down to see the ship, was on two HC specials, and will be prominent in a
book to come out in September. How much more do I need? My work was pretty
damn solid and I enjoy arguing about how complex the fuel system is on my
boat more at this point in life.
--
Roger Long
cavelamb himself
> "cavelamb himself" <cave...@Xearthlink.net> wrote >
>
>>Since you have studied this incident so long, has anyone ever considered
>>the effect of the temperature of the water on the fracture strength of
>>the steel uesd to build the hull?
>
>
> Yes, and it certainly had a bearing on the details of the event but not the
> big picture. She might have broken at 15 - 16 degrees instead of 10 - 12 if
> it had been on a summer day.
>
AH, yeah. :)
Thos balmy summer days in the Norht Atlantic..
I think he probably meant considerably warmer waters.
>>In his book "Structures: Or Why Things Don't Fall Down", J.E. Gordon
>>analizes the changes in physical properties that the near freezing water
>>would have had on the steels of teh day.
>
>
> Great book. I have read it although quite some time ago.
Why does that no surprise me?
> --
> Roger Long
>
>
>
Larry
13g2000hsb.googlegroups.com:
> Engineering is also different from research.
I like what Albert Einstein said to a newspaper reporter:
"If we know what we were doing, we couldn't call it "research"."
I have a t-shirt with that and his picture on it....(c;
My ex-wife's aunt was his personal secretary for decades at Princeton. Her
house was full of "stuff" he gave her, awards, accolades, certificates,
honoraria, plaques, etc. She made sure he had socks on before anyone
important saw him....(c;
Larry
news:47d7ef76$0$6146$4c36...@roadrunner.com:
> My work was pretty
> damn solid and I enjoy arguing about how complex the fuel system is on
> my boat more at this point in life.
>
>
....And we are honored to rag on you about it...(c;
Any more ham radio history show up, by the way? Any more contact with ARRL
or the others?
Larry W4CSC
Roger Long
>
> Any more ham radio history show up, by the way? Any more contact with
> ARRL
> or the others?
No, I'm sorry to say and I apologize for dropping the ball on further
research and contact. I bit off way more boat projects than I can chew on
this winter and chewing on anything began to become a big problem shortly
after Christmas (you probably saw my post above) which has really sapped my
energy. I hope to get back to finding out more about my Grandfather's early
radio experiments but I'm now facing for paying for land storage and marina
dock at the same time while not sailing i(really, really, bad thing!) if I
don't get an heroic mount of work done in the next couple of months. And,
I still feel like shit.
--
Roger Long
Larry
Ah, I see. I'm still really interested in his historic work. When you get
back into it, at some point, please keep me informed.
Thanks
I still think he was one of the earliest hams I know of to go on the air,
predating all the famous guys by years and years! Most interesting....(c;