Hull material types. (question)
John Lee
As a prospective buyer of a sailing boat, I have specific interest in
learning more about different hull material for strength and
maintainability. In fiberglass hull, I been noticing many are a
sandwich construction with hardwood or synthetic core. Also, in some
rare cases, there were solid fiberglass hulls. Purely from strength and
durability stand points of view, which is stronger hull? Pros and cons?
What about the metal hull? Aside from being heavier, how does it
compare with fiberglass in terms of durability, safety, and livability
(while cruising)? How about aluminum?
Type of boats in consideration is for 50+ feet range, if that makes
difference in hull choice.
Sorry to dump all questions at once, but I do value the experienced
opinion.
Thanks!
Steve
can be argued that core material allows for a stiffer hull from thinner
fiberglass material. I still believe in a solid glass build up but then I
want a Heavy Displacement hull. For comparision, I'm building a 38ft INGRID
with a 32ft LWL and a displacement of 26,000 lb (8,000 in lead ballast).
Todays production boats of this size would weigh in at around 20,000 lb
displacement. The ballast would remain about the same and would be in the
form of a fin rather than the full keel I have. The hull and deck would be
foam or bulsa cored.
Inspite of all the claims about using core material to build a stiffer hull,
I really believe it's a matter of hull cost. Since the 70s when the oil
crissis caused resin prices to triple, designers and builders have been
minimizing the amount of resin and glass fiber material in the hull.
Me, I'll stay with my solid glass layup.
With regard to you comment about steel hulls being heavyer; in the size
range your considering, steel 'could' be the lighter material. From about 40
ft up, steel becomes a very attractive building material for both weight and
ease of construction for custom boats (one off).
Steel hulls will be colder in cold climates and hotter in hot climates. And
much more noise when sailing. Look for a boat with plenty of insulation.
Maintenance is somewhat relative to how the boat is finished out. A glass
hull with a lot of teak/wood trim can take more time and money than a steel
boat with no wood trim.
Just my opinion and you will get plenty from others.
Steve
s/v Good Intentions
Douglas King
> As a prospective buyer of a sailing boat, I have specific interest in
> learning more about different hull material for strength and
> maintainability. In fiberglass hull, I been noticing many are a
> sandwich construction with hardwood or synthetic core. Also, in some
> rare cases, there were solid fiberglass hulls. Purely from strength and
> durability stand points of view, which is stronger hull? Pros and cons?
Stronger in what way? Stiffness? Yield? Puncture resistance? There are
several ways to measure strength, and some confer different benefits.
Stiffness is of more concern to a racer. Yield strength and puncture
resistance are critically important to any vessel though. Cores can
increase both pretty dramatically, fiberglass really isn't all that
strong inherently and it is kind of brittle.
> What about the metal hull? Aside from being heavier, how does it
> compare with fiberglass in terms of durability, safety, and livability
> (while cruising)? How about aluminum?
>
> Type of boats in consideration is for 50+ feet range, if that makes
> difference in hull choice.
Yup. AFAIK there are relatively few solid glass 50'+ size boats. In
larger boats, steel and aluminum become more attractive because of the
higher ratio of hull volume to surface area. In other words, a 50-footer
built of steel can be a graceful vessel, 25-footer would be a tank. With
aluminum, the size threshold drops a bit but it's still there. For
example, few vessels over 100' LOA are built of fiberglass....
Steve wrote:
>
> Your correct, there are few if any large boats built of solid figerglass. It
> can be argued that core material allows for a stiffer hull from thinner
> fiberglass material. I still believe in a solid glass build up but then I
> want a Heavy Displacement hull. For comparision, I'm building a 38ft INGRID
> with a 32ft LWL and a displacement of 26,000 lb (8,000 in lead ballast).
There's a big difference between a 38-footer and a 50-footer. Also in
amateur and professional construction- actually most home-built boats
are far better built and finished than most production boats, but I mean
the hi-tech options which are out of reach for home builders.
> Todays production boats of this size would weigh in at around 20,000 lb
> displacement. The ballast would remain about the same and would be in the
> form of a fin rather than the full keel I have. The hull and deck would be
> foam or bulsa cored.
Let's not overlook the big difference in hull form and configuration,
which should not be ignored when considering construction material.
> Inspite of all the claims about using core material to build a stiffer hull,
> I really believe it's a matter of hull cost. Since the 70s when the oil
> crissis caused resin prices to triple, designers and builders have been
> minimizing the amount of resin and glass fiber material in the hull.
You may be right in some cases of low-tech mass-produced boats, but the
labor costs of doing composite and core construction far FAR outweight
the reduced material cost.
And it is quite well established that cored hulls can be stronger in
every way as well as lighter than all-cloth/mat layup.
> With regard to your comment about steel hulls being heavyer; in the size
> range your considering, steel 'could' be the lighter material. From about 40
> ft up, steel becomes a very attractive building material for both weight and
> ease of construction for custom boats (one off).
>
> Steel hulls will be colder in cold climates and hotter in hot climates. And
> much more noise when sailing. Look for a boat with plenty of insulation.
> Maintenance is somewhat relative to how the boat is finished out. A glass
> hull with a lot of teak/wood trim can take more time and money than a steel
> boat with no wood trim.
Agreed on these points. There is also the matter of maintenance- having
been in the Navy, I have less than zero interest in trying to keep a
steel boat myself. But this is a matter of personal preference, steel
has a lot of benefits. Aluminum might be a better choice in many ways,
although it's a lot more expensive.
Fresh Breezes- Doug King
--
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John
caution you, however, to have any metal boat you consider buying surveyed by
a marine surveyor experienced and accredited in metal boats.
--
John Matott
Fern Ridge Boatworks
1420-A North 14th Street
Olde Towne Marina
Fernandina Beach, FL 32034
jo...@fernridgeboats.com
"John Lee" <jn...@us.oracle.com> wrote in message
news:38B45511...@us.oracle.com...
> Folks,
> As a prospective buyer of a sailing boat, I have specific interest in
> learning more about different hull material for strength and
> maintainability. In fiberglass hull, I been noticing many are a
> sandwich construction with hardwood or synthetic core. Also, in some
> rare cases, there were solid fiberglass hulls. Purely from strength and
> durability stand points of view, which is stronger hull? Pros and cons?
>
> What about the metal hull? Aside from being heavier, how does it
> compare with fiberglass in terms of durability, safety, and livability
> (while cruising)? How about aluminum?
>
> Type of boats in consideration is for 50+ feet range, if that makes
> difference in hull choice.
>
John Lee
requirements. I am looking for a distance cruiser with safety as number
one concern. My worst fear is being out in the middle of pacific with
my family and hitting a floating object that will cause below water hull
damage large enough to sink the boat! I realize such possibility may be
lower than other more immediate concerns like driving home without
getting into fatal accident, or getting hit by a lighting.
Nevertheless, it's one of these concerns I feel necessary to address
before I can feel confident about venturing out into the open sea.
Thanks again!
Douglas King wrote:
>
> John Lee wrote:
> > As a prospective buyer of a sailing boat, I have specific interest in
> > learning more about different hull material for strength and
> > maintainability. In fiberglass hull, I been noticing many are a
> > sandwich construction with hardwood or synthetic core. Also, in some
> > rare cases, there were solid fiberglass hulls. Purely from strength and
> > durability stand points of view, which is stronger hull? Pros and cons?
>
> Stronger in what way? Stiffness? Yield? Puncture resistance? There are
> several ways to measure strength, and some confer different benefits.
>
> Stiffness is of more concern to a racer. Yield strength and puncture
> resistance are critically important to any vessel though. Cores can
> increase both pretty dramatically, fiberglass really isn't all that
> strong inherently and it is kind of brittle.
>
> > What about the metal hull? Aside from being heavier, how does it
> > compare with fiberglass in terms of durability, safety, and livability
> > (while cruising)? How about aluminum?
> >
> > Type of boats in consideration is for 50+ feet range, if that makes
> > difference in hull choice.
>
John
"John Lee" <jn...@us.oracle.com> wrote in message
news:38BC938A...@us.oracle.com...
> Do you have a website where I can browse?
>
> John wrote:
> >
> > We build strictly in aluminum, so my prejudice runs to that material. I
> > caution you, however, to have any metal boat you consider buying
surveyed by
> > a marine surveyor experienced and accredited in metal boats.
> >
> > --
> > John Matott
> > Fern Ridge Boatworks
> > 1420-A North 14th Street
> > Olde Towne Marina
> > Fernandina Beach, FL 32034
> > jo...@fernridgeboats.com
> >
> > "John Lee" <jn...@us.oracle.com> wrote in message
> > news:38B45511...@us.oracle.com...
> > > Folks,
> > > As a prospective buyer of a sailing boat, I have specific interest in
> > > learning more about different hull material for strength and
> > > maintainability. In fiberglass hull, I been noticing many are a
> > > sandwich construction with hardwood or synthetic core. Also, in some
> > > rare cases, there were solid fiberglass hulls. Purely from strength
and
> > > durability stand points of view, which is stronger hull? Pros and
cons?
> > >
> > > What about the metal hull? Aside from being heavier, how does it
> > > compare with fiberglass in terms of durability, safety, and livability
> > > (while cruising)? How about aluminum?
> > >
> > > Type of boats in consideration is for 50+ feet range, if that makes
> > > difference in hull choice.
> > >
John
This risk can be addressed in the design and construction of a vessel
regardless of the material. For example, a boat we have under construction
has five watertight compartments and a double hull in several areas. Proper
bilge management is also important.
--
John Matott
Fern Ridge Boatworks
1420-A North 14th Street
Olde Towne Marina
Fernandina Beach, FL 32034
jo...@fernridgeboats.com
"John Lee" <jn...@us.oracle.com> wrote in message
news:38BC931E...@us.oracle.com...
Joe Della Barba
wrote:
>This is a multi-part message in MIME format.
>--------------47D5C49B4DC7A3582B13810A
>Content-Type: text/plain; charset=us-ascii
>Content-Transfer-Encoding: 7bit
>
>Thanks for you insightful comments. Let me further qualify my
>requirements. I am looking for a distance cruiser with safety as number
>one concern. My worst fear is being out in the middle of pacific with
>my family and hitting a floating object that will cause below water hull
>damage large enough to sink the boat! I realize such possibility may be
>lower than other more immediate concerns like driving home without
>getting into fatal accident, or getting hit by a lighting.
>Nevertheless, it's one of these concerns I feel necessary to address
>before I can feel confident about venturing out into the open sea.
>
>Thanks again!
>
Keep in mind that fiberglass is niot suited to either amateur or
one-off construction. THe reason there are few 100 ft fiberglass boats
is that the mod would be monumentally expensive. You need a big
production run to spread the cost over. BTW, have you considered
multi-hulls? Most of them are unsinkable.
Joe
John Chase
unsinkable ship that now lies at the bottom of the ocean.
JACQUES_MERTENS
mind that fiberglass is niot suited to either amateur or
> one-off construction.
Disagree: FG with a foam core is perfect for amateurs.
>THe reason there are few 100 ft fiberglass boats
> is that the mod would be monumentally expensive. You need a big
> production run to spread the cost over.
In that size, they are rarely build in a mold and I would guess that around
50% of the large yachts are now built in RFG with some kind of core.
> BTW, have you considered
> multi-hulls? Most of them are unsinkable.
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
Lew Hodgett
> Keep in mind that fiberglass is niot suited to either amateur or
> one-off construction.
Guess it was a good idea I was unaware of this before I built my hull.
>THe reason there are few 100 ft fiberglass boats
> is that the mod would be monumentally expensive. You need a big
> production run to spread the cost over.
Assume you are referring to a female mold.
Just curious, when is the last time you saw a boat over 50 ft being
built.
> BTW, have you considered
> multi-hulls? Most of them are unsinkable.
I don't have a clue what you are smoking, but if you sold some of it,
could probably make a lot of money. Might have a few other problems
though.
Lew
S/A: Challenge (Under Construction, still fairing in the Southland)
Visit:<http://home.earthlink.net/~lewhodgett> For Pictures
There are no problems, only varying degrees of challenging
opportunity.
Joe Della Barba
Sometimes this crappy laptop keyboard does not lend itself to fast
typing, but spelling errors notwithstanding I will stand by my
statements.
I used to work summers at a builder of trimarans, so I do have a
little knowledge of boatbuilding.
Fiberlglass is a nasty, dangerous, and smelly substance to work with.
To do a good job on a fiberglass hull requires tooling and a climate
controlled environment that would be cost-prohibitive for a one off
amateur builder. If your hull came out well you are either very
skilled or lucky. You might be the ace layup man of all time, but not
everyone has those skills and it is not very easy to QC a finished
hull. Many one-off systems involve a foam core, which is NOT a good
idea. You can go to www.yachtsurvey.com for an expert dissertation on
problems with cored hulls. I worked on a Krogen 42 with a foam core
hull that must of had hundreds of gallons of water in the core. We had
to wait hours after drilling a thru-hull hole for the water to quit
pouring out.
As far as unsinkable multi-hulls, every one I have been on had various
watertight bulkheads and no ballast, so it would take a chainsaw and
some time to get a piece that would sink. One of ours was hit by a
freighter and lost 2 of the 3 bows and still made port.
BTW, I would be curious as to what type of boat you made. I worked on
a few boats that were finished froma bare hull for variuos people over
the years.
Joe
Lew Hodgett
> Fiberlglass is a nasty, dangerous, and smelly substance to work with.
Must be complaining about the styrene smell in polyester resin system.
> To do a good job on a fiberglass hull requires tooling and a climate
> controlled environment that would be cost-prohibitive for a one off
> amateur builder. If your hull came out well you are either very
> skilled or lucky.
Absolutely not.
No rocket science involved, just some basics.
Epoxy, knitted glass and Airex are very forgiving.
>You might be the ace layup man of all time, but not
> everyone has those skills and it is not very easy to QC a finished
> hull.
Strictly OJT.
Hull was laid up outdoors in Los Angeles. No big deal.
>Many one-off systems involve a foam core, which is NOT a good
> idea.
Absolute nonsense; however, not all cores are equal. Personally, would
never consider balsa for anything but model airplanes.
> You can go to www.yachtsurvey.com for an expert dissertation on
> problems with cored hulls.
If you define an expert as someone who is more that 50 miles from
home, I guess that qualifies.
> I worked on a Krogen 42 with a foam core
> hull that must of had hundreds of gallons of water in the core. We had
> to wait hours after drilling a thru-hull hole for the water to quit
> pouring out.
It appears you are describing the specific results of some poor
construction.
So, what is the relavancy in the overall market?
> BTW, I would be curious as to what type of boat you made.
See below.
Glenn Ashmore
just had an in progress survey done on my hull. The report that was sent
to my insurance company states "...quality of construction far above normal
production levels." "The hull is exceptionaly fair..."
Some facts:
While I have built several smaller boats, I have never built is FRP
before. My layup crew consisted of who ever I could sucker into
volunteering and they put down up to 1,200 square feet of glass in a
session. And it was all tight and free of viods.
As far as smell goes, there ain't none with epoxy. My wife helped with the
layup and she is so sensitive she can't stand the smell of my dog after he
has had a bath.
The building shed is a tent that ranges from 40F to 110F. Using the
correct resin you don't need to worry so much about environment.
At least half the production sailboats being built today have some kind of
cored construction. Done right, cored hulls are just as strong as solid
ones and a heck of a lot lighter. Pascoe is more than a little bigoted on
this point. He is also a power boat surveyor and that is where core
problems occur most often. BTW, there is no foam or balsa in my core.
As far as unsinkable catamarans go, tell that to the owner of those two
bows sticking out of the water at the West end of Port Maria, Jammaca
harbor. You may be right, They don't sink.... All the way that is.<g>
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.mindspring.com/~gashmore
Glenn Ashmore
Thanks for the complement but it don't take any exceptional skill. I
have less of that than many here. It just takes patience. (and a very
understanding wife),g>
I just don't like someone making a blanket condemnation of a building
method for amateurs that many of us have mastered and could be the only
method available for some of us who lack the REAL wood working skills
required to build in traditional ways.
John Abercrombie
(to contradict a statement by another poster that the "average
builder" will have a tough time building a high quality hull..)
>Sorry fella, you're talking through your hat. Check out my web site. I
>just had an in progress survey done on my hull. The report that was sent
>to my insurance company states "...quality of construction far above normal
>production levels." "The hull is exceptionaly fair..."
>
You are being WAY too modest. You are not an average builder and your
project is much beyond what most home builders could manage: custom
built devices for wetting out cloth, complete vacuum bagging, etc etc.
You obviously have wood and metalworking skills plus the
engineering/technical knowledge and financial resources to deal with
building what would be for most folks a "high-tech" boat.
I doubt that many successful amateur builders (those who complete
major projects- a fraction of those who start) could manage your
project.
John
SailDesign
I felt it was time to put in my 2 cents. Foam core is the reason that so many
of todays sailboats, production and custom, are so fast. The entire range of
J-Boats, from the ludicrously slow to the "metric 5" series, have foam cores.
These boats are well-built but quickly and to a price that is affordable to
mosdt who are interested. The one-off foam cored hull DOES require some
elbow-grease to get fair, but it is not beyond the average Joe, as they are so
fond of demonstrating. Sure, places like Eric Goetz's shop have some extremely
techie methods and the most experienced people available, but it boils down to
how many hours you spend with a longboard in hand.
REALLY light boats come with experience and a good engineer/designer, while
fairness comes with hard work. I would not consider building in glass with no
core, and for durability, I would not consider the lightweight wood techniques.
The two most popular techniques for building lightweight boats in wood these
days are cold-moulding and strip planking. Cold moulding, to my mind, is just
as hard as laying up fiberglass, but then I am not a woodworker, and you don't
have to cut glass that accurately. Strip-planking still requires you to cut
and trim wood, and THEN you still need to apply a surface of glass (it's realy
just like using THICK core and thin skins).
Well, got to run.
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/private/scbweb/home.htm
Joe Della Barba
have to defer to you as far as laying up with epoxy. Some peope become
allergic to it, but I have been using West System for years for small
jobs and it doesn't bother me.
If I was buying a new boat I wouldn't mind buying a balsa core boat if
she was made with vinylester and SCRIMP process. My two big objections
to foam were that once water gets in it migrates all throughout the
foam and destroys it and it can shear apart between hulls. End grain
balsa limited water migration much more than foam did. CSY built some
foam core boats that had the inner and outer layers shear apart.
Time does march on, however, and a little research I did last night
shows that foam may overtake balsa in new boats. There are new foam
cores out there now that do not have the water migration problems of
the stuff I have seen in older boats. C&C is using a foam now called
core cell to replace balsa. Here is a quote from them:
C&C Yachts are one of the first to take advantage of cored laminates.
Cored laminates produce stronger, lighter and better performing
sailboats. The weight saved through the use of advanced construction
techniques can be used to further enhance performance by allowing
increased ballast/displacement ratios which increases sail carrying
ability and stability. The C&C Xpress Series features Core Cell(
structural linear foam core. It is exceptionally strong, light weight
and water-resistant. This latest development in core delivers
stiffness and strength and eliminates the concerns of water migration
and core deterioration. A composite laminate utilizing Core Cell foam
allows the boat builder latitude to design a performance structure
taking advantage of the high tensile strength of uni-directional
non-woven fabrics.
Joe - the guy who spoke too quicly about foam.
BTW - I don't know anything about a partly submereged catamaran in
Jamaica, but unsinkable means won't sink when full of water. Level
flotation is something else. My boat would be on the bottom if she was
full, which would be kinda crappy if it was a long swim home :(
Lew Hodgett
<snip>
> If I was buying a new boat I wouldn't mind buying a balsa core boat if she was made with vinylester and SCRIMP process.
You are gutsy. I could have bought a finished hull of the boat I'm
building for a lot less time and money if I would have been willing to
accept balsa core.
> My two big objections
> to foam were that once water gets in it migrates all throughout the
> foam and destroys it and it can shear apart between hulls.
Not if it's closed cell PVC made without isocyanates such as Airex.
Divinycell in a hull is another matter.
It is isocyanate based and thus less costly to produce; however, it
does not possess the impact properties of Airex.
> End grain
> balsa limited water migration much more than foam did.
Rubbish. Absolutely not true regardless of what Baltek tries to
promote.
The most positive thing I can think of to say about basla as a hull
core material is that it's CHEAP.
>CSY built some
> foam core boats that had the inner and outer layers shear apart.
> Time does march on, however, and a little research I did last night
> shows that foam may overtake balsa in new boats. There are new foam
> cores out there now that do not have the water migration problems of
> the stuff I have seen in older boats. C&C is using a foam now called
> core cell to replace balsa.
Sounds like Thom Johannsen is having an impact in the market place,
especially since C&C and Core-Cell are practically neighbors.
Last I heard, after Thom and Lonza (AIREX manufacturer in Switzerland)
parted ways, he has hooked up with Core-Cell.
Here is a quote from them:
Twenty years ago, that was the Airex presentation given by Johannsen.
Maybe the Airex patents have expired. Personally haven't checked out
Core-Cell yet; however, will when it's time to buy more foam for the
deck and bulkheads.
JACQUES_MERTENS
more than 25 years now and BTW, I also worked for Krogen: if there was water
in a hull, it could not have been in the core since they use closed cell
foam!
You do not need climate control to build a fiberglass boat and resins are
not more dangerous than steel plates or finger cutting bandsaws.
Amateurs can do a good job with polyester and foam core: several of our
amateur built hulls received the Lloyds A100 certification.
The purpose of my post is not to argue but to make clear that foam core is
probably the best material today for amateur boat building of large boats.
Joe Della Barba <jo...@spambites.earthlink.net> wrote in message
news:38c01076...@news.earthlink.net...
> On Fri, 03 Mar 2000 17:14:50 GMT, Lew Hodgett
> <lewho...@earthlink.net> wrote:
>
> >Joe Della Barba wrote:
> >
> >> Keep in mind that fiberglass is niot suited to either amateur or
> >> one-off construction.
> >
> >Guess it was a good idea I was unaware of this before I built my hull.
> >
> >>THe reason there are few 100 ft fiberglass boats
> >> is that the mod would be monumentally expensive. You need a big
> >> production run to spread the cost over.
> >
> >Assume you are referring to a female mold.
> >
> >Just curious, when is the last time you saw a boat over 50 ft being
> >built.
> >
> >> BTW, have you considered
> >> multi-hulls? Most of them are unsinkable.
> >
> >I don't have a clue what you are smoking, but if you sold some of it,
> >could probably make a lot of money. Might have a few other problems
> >though.
> >
> >
> >Lew
> >
> >S/A: Challenge (Under Construction, still fairing in the Southland)
> >
> >Visit:<http://home.earthlink.net/~lewhodgett> For Pictures
> >
> >There are no problems, only varying degrees of challenging
> >opportunity.
> Sometimes this crappy laptop keyboard does not lend itself to fast
> typing, but spelling errors notwithstanding I will stand by my
> statements.
> I used to work summers at a builder of trimarans, so I do have a
> little knowledge of boatbuilding.
> Fiberlglass is a nasty, dangerous, and smelly substance to work with.
> To do a good job on a fiberglass hull requires tooling and a climate
> controlled environment that would be cost-prohibitive for a one off
> amateur builder. If your hull came out well you are either very
> skilled or lucky. You might be the ace layup man of all time, but not
> everyone has those skills and it is not very easy to QC a finished
> hull. Many one-off systems involve a foam core, which is NOT a good
> idea. You can go to www.yachtsurvey.com for an expert dissertation on
> problems with cored hulls. I worked on a Krogen 42 with a foam core
> hull that must of had hundreds of gallons of water in the core. We had
> to wait hours after drilling a thru-hull hole for the water to quit
> pouring out.
Joe Della Barba
<JACQUES...@email.msn.com> wrote:
>That yachtsurvey.com is pure BS. I designed and built foam cored hulls for
>more than 25 years now and BTW, I also worked for Krogen: if there was water
>in a hull, it could not have been in the core since they use closed cell
>foam!
>You do not need climate control to build a fiberglass boat and resins are
>not more dangerous than steel plates or finger cutting bandsaws.
>Amateurs can do a good job with polyester and foam core: several of our
>amateur built hulls received the Lloyds A100 certification.
>The purpose of my post is not to argue but to make clear that foam core is
>probably the best material today for amateur boat building of large boats.
>--
>Jacques Mertens
>Boat Plans OnLine
>http://www.bateau.com
>
>Joe Della Barba <jo...@spambites.earthlink.net> wrote in message
I have discovered not all foam cores are problematic, but I would like
to know two things:
1. How did all the water get in the Krogen if not in the core?
2. As far as www.yachtsurvey.com, do you have a specific statement you
think is BS? This guy seems to know what he is talking about, but I
like to keep an open mind.
Joe
Suzi Q & Tommy Bloomer
closed cell foam not absorb water? Everything absorbs water. I have
repaired several foam cored hulls with water in the "closed cell foam."
Look up the mechanical properties on any foam core material. If they have
bothered to measure water absorption, you might find interesting numbers.
The point of the yachtsurvey.com article is that there is a lot of mass
produced crap out there in the boat market. Most manufacturers of
production boats use foam - or any other core - to cut costs and speed-up
production. I strongly disagree with your opinion that "foam core is
probably the best material today for amateur boat building of large boats,"
I think that C-Flex is a much better one-off method, especially if you are
building over CNC cut frames. In my experience, having built with both
materials, the C-Flex produced a fairer hull, and the actual labor was
considerably less.
Tom Bloomer
"Joe Della Barba" <jo...@spambites.earthlink.net> wrote in message
news:38c54595...@news.earthlink.net...
JACQUES_MERTENS
but to state that foam sandwich is a great material for amateurs.
For the water in the Krogen, I never saw it, you are the one that mentioned
it.
About yachtsurvey.com, there have been a number of posts about that guy here
last year. You may find them with a search in Dejanews. If I remember well,
he is some kind of "surveyor" that got a liability problem or even lost a
lawsuit for a batched survey he did of a foam cored boat.
For serious information about foam cores, check the back issues of
Professional Boat Builder magazine at:
http://www.proboat.com/
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
Joe Della Barba <jo...@spambites.earthlink.net> wrote in message
news:38c54595...@news.earthlink.net...
JACQUES_MERTENS
in composite text books and professional publications is wrong? And my tests
where wrong too?
And the experts writing for Professional Boat Builder are wrong too? See
issues 51 and 52 for figures and specifications with numerous tables. That
is a serious look at foam cores, not like the unsubstantiated rantings on
yachtsruvery.com.
Look at your statement: "everything absorbs water . . ." I am a living proof
that this is false: I never absorb water, only beer. Please, be serious
You may have seen water between the skin and core of a poorly built boat but
not in a closed cell foam.
Also, I am referring to foam such as Airex, not to Styrofoam and other junk.
Not balsa either.
I did waste 5 minutes reading the stuff about cores at yachtsurvey.com: not
one figure, not one test only anecdotal stuff about cheap cores, one picture
of something that I would not even use to insulate a fridge and all defects
are described as a result of poor workmanship. Only one bibliographic
reference and it is about resins, not core. Where are the facts? Show me the
figures, the lab tests.
The article is clearly biased and the writer never supports his views with
figures.
As for C-Flex, it is difficult to use, expensive and produces heavy hulls.
But I don't have time to argue: I sailed an Airex cored boat half around the
world, hit docks, ran aground, did sloppy drilling for tru-hulls and the
core never took water.
For all potential builders out there: take a close look at foam cores, they
are the best choice for larger boats built one-off.
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
Suzi Q & Tommy Bloomer <not....@address.com> wrote in message
news:sccf3d7...@corp.supernews.com...
Harry Krause
>
> I can't believe that post! Closed cell foam absorbs water! Then all the data
> in composite text books and professional publications is wrong? And my tests
> where wrong too?
> And the experts writing for Professional Boat Builder are wrong too? See
> issues 51 and 52 for figures and specifications with numerous tables. That
> is a serious look at foam cores, not like the unsubstantiated rantings on
> yachtsruvery.com.
>
> Look at your statement: "everything absorbs water . . ." I am a living proof
> that this is false: I never absorb water, only beer. Please, be serious
>
> You may have seen water between the skin and core of a poorly built boat but
> not in a closed cell foam.
> Also, I am referring to foam such as Airex, not to Styrofoam and other junk.
> Not balsa either.
>
And therein lies the rub, at least for foam core below the water line.
There have been reports of water getting between the skin and the core
of boats cored below the water line. That can turn into a really
interesting problem.
--
Harry Krause
------------
Practice safe fax...ALWAYS use a cover slip.
Joe Della Barba
<JACQUES...@email.msn.com> wrote:
>As I said in my post, the purpose of my response was not to argue forever
>but to state that foam sandwich is a great material for amateurs.
>For the water in the Krogen, I never saw it, you are the one that mentioned
>it.
>About yachtsurvey.com, there have been a number of posts about that guy here
>last year. You may find them with a search in Dejanews. If I remember well,
>he is some kind of "surveyor" that got a liability problem or even lost a
>lawsuit for a batched survey he did of a foam cored boat.
>For serious information about foam cores, check the back issues of
>Professional Boat Builder magazine at:
>http://www.proboat.com/
>
>--
>Jacques Mertens
>Boat Plans OnLine
>http://www.bateau.com
>
>Joe Della Barba <jo...@spambites.earthlink.net> wrote in message
>news:38c54595...@news.earthlink.net...
>> >Joe Della Barba <jo...@spambites.earthlink.net> wrote in message
>>
>> I have discovered not all foam cores are problematic, but I would like
>> to know two things:
>> 1. How did all the water get in the Krogen if not in the core?
>> 2. As far as www.yachtsurvey.com, do you have a specific statement you
>> think is BS? This guy seems to know what he is talking about, but I
>> like to keep an open mind.
>> Joe
>>
>
>
The Krogen was leaking from new holes not close to any others. The
closed-cell foam in my rudder does a damn fine job of absorbing water.
Water seems to get in the foam and break it down. This is a pretty
common problem and I have seen rudders freeze and split.
I did a quick web search on foam and balsa properties and balsa had
superior strength in shear and compression.
I did a quick Deja News search on David Pascoe and got a ton of
whining from idiots who were mad because their Bayliners got insulted,
but I didn't see any mentions of any lawsuits and no posts from anyone
who had any solid information to contradict him.
Joe
Leo Voorneveld BLVRD-the Netherlands
if you Cover foam with polester there is a good change that moistere can
travel through the polyester and find a place between foam and polyester.
On the other hand if it is covered with epoxy you have a far better product.
I wonder how old the article is of yachtsurvey.com ?
In the beginning there were ofcourse problems, as it is with all materials.
But the understanding of the foams is way better now.
He stated that most problems of foamcores were the fault of the labours, how
many cheap builders that used coremat (is a way to fill quickly a laminate)
with a very low amount of resin ??
I have seen some, no data so it is not a proof Jacques ;*)
And at www.boatbuilding.com there you can find a (to me) new article of the
hand of Sponberg about foamcores.
Actualy all boats not build out of pure wood are bad ;*)
Cheers Leo
Lew Hodgett
> The Krogen was leaking from new holes not close to any others. The
> closed-cell foam in my rudder does a damn fine job of absorbing water.
> Water seems to get in the foam and break it down. This is a pretty
> common problem and I have seen rudders freeze and split.
<snip>
Sounds like a classic case of oranges and apples.
Seems a lot of rudders get filled with water; however, typical foams
found in rudders are not the same as structural foams such as Airex
found in the hull.
A lot of the rudder structures I'm aware of are formed by glassing the
rudders halves together together complete with the rudder post
inserted and then filling the cavity with an expanding foam.
A completely different world than an Airex cored hull structure.
Suzi Q & Tommy Bloomer
Also worked for two boat building companies. I have seen how well foam
cores soak up water. One of the worst cases I saw was an Airex cored hull
with severe delamination below the waterline. That boat was less than 5
years old. I have probably fixed (attempted to fix) a dozen foam cored
sailboat rudders from as many boat manufacturers. Balsa in the deck?
You're ok until some idiot forgets to bed his hardware with 5200, then it's
time for "BIG BILL".
Would I use foam core in a boat? Yes, but not below the waterline - except
for stiffiner sections where it would be there just to hold the shape while
laminating. Above the waterline, I would use foam core, but never under any
laminate that I intended to paint a dark color. The stuff has a low HDT.
Balsa has a high HDT - paint yer boat black.
I would recomend foam core for a one-off amature project, IF the boat was
small, trailerable, never to be kept in the water for extended periods of
time. Otherwise you might find yourself with a floating sponge.
I agree with everything Pasco says on his yacht survey web site. He is
dealing with the long term results of the applied theory of 'High Tech
Composites'. My experience in the real world has been the same. The K.I.S.
principal seems to escape people after they get an engineering degree - go
figure?
Tom Bloomer
> The Krogen was leaking from new holes not close to any others. The
> closed-cell foam in my rudder does a damn fine job of absorbing water.
> Water seems to get in the foam and break it down. This is a pretty
> common problem and I have seen rudders freeze and split.
Douglas King
>
> >As I said in my post, the purpose of my response was not to argue forever
> >but to state that foam sandwich is a great material for amateurs.
That's perhaps best taken with a grain of salt. In years past,
construction methods from V-bottom plywood to laminated newspaper have
been touted as "ideal for amateurs." The material alone does not make a
boat great, or easy to build. I'd agree that for foam core FG is a
better choice than some others, especially for light-displacement boats.
Joe Della Barba wrote:
> The Krogen was leaking from new holes not close to any others. The
> closed-cell foam in my rudder does a damn fine job of absorbing water.
> Water seems to get in the foam and break it down. This is a pretty
> common problem and I have seen rudders freeze and split.
Well, anything with water in it will do that- it's not the foam that's
the problem. And just because the builder chose the wrong foam (or the
cheaper one) or did not bond the skins properly, that doesn't mean that
ALL foam absorbs water, or is bad.
One thing that needs to be recognized right away is that all foam is not
created equal. Much of what is sold as "closed-cell foam" isn't really.
TO give a graphic example, we have a float cap for a dinghy mainsail
which provided bouyancy when capsized. The idea was to prevent the boat
from turning turtle. It worked great for five minutes, then the boat
turned turtle anyway. When we got it righted and got ashore, I could
wring water out of it like a sponge. Contrast that with the foam
flotation panels in our lifejackets, which were immersed for an equal
length of time and did not absorb one drop (fortunately).
> I did a quick web search on foam and balsa properties and balsa had
> superior strength in shear and compression.
That seems to depend on who does the tests and on which foam they're
testing.
And strength properties are not the same as resistance to water
absorption.
The Gougeon Brothers use a composite of foam and wood laminates; they
say it's about 5% lighter for the same strength and 15% stronger for the
same weight. Note- the foam is the core, the wood is the skin.
In any event, there are many examples of foam-cored boats going for
years and years of hard service with no problems. If you don't like foam
core, don't buy a boat with it. If you do, then check it carefully
(which is good advice for any purchase, actually).
Fresh Breezes- Doug King
--
This is what we look like when we're at our best:
http://recboats.hsh.com/45.htm
**************************
Spambots, feed upon your own kind!
JACQUES_MERTENS
water goes through a polyester skin to get in a foam core, then all
polyester boats should be sinking no?
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
Harry Krause <hkr...@capu.net> wrote in message
news:38C67633...@capu.net...
> JACQUES_MERTENS wrote:
snip
JACQUES_MERTENS
experience with very cheap foam or poorly build boats then generalize and
condemn all foam cores.
Insulation foam are not core foams. Good foams like Airex does not absorb
water and if water gets between the skin and the core it is due to poor
workmanship. Foam must be bedded in a slurry type compound or as I specify,
chemically bonded to the resin. It is very easy to do a proper job and if
somebody is seriously interested, they should take serious advice, not
listen to unsubstantiated gossips. I already listed PBO but also see the web
sites of some amateurs that have build their boats with foam cores.
Harry Krause
Jacques...
There is no shortage of "poor workmanship" among factory built and home
built boats.
--
Harry Krause
------------
Modem: A deterrent to telephone solicitors.
Steven Shelikoff
>
> There is a terrible amalgamation in the discussion here: people have bad
> experience with very cheap foam or poorly build boats then generalize and
> condemn all foam cores.
>
> Insulation foam are not core foams. Good foams like Airex does not absorb
> water and if water gets between the skin and the core it is due to poor
> workmanship. Foam must be bedded in a slurry type compound or as I specify,
> chemically bonded to the resin. It is very easy to do a proper job and if
> somebody is seriously interested, they should take serious advice, not
> listen to unsubstantiated gossips. I already listed PBO but also see the web
> sites of some amateurs that have build their boats with foam cores.
One valid measure of the worth of a particular material is it's
tolerance to poor construction practices and quality control. Foam
below the waterline doesn't pass that test very well. If you're
building your own boat and know what you are doing or you're relying on
a builder of known high quality control, it's not as much of an issue as
if you're buying from a mass manufacturer.
Steve
--
/ / /
\ \ \ mailto:shel...@averstar.com
/ / / http://www.averstar.com/customers/maritime.html
Suzi Q & Tommy Bloomer
The guy on the laminating crew at "name your boat company" doesn't care if
the core is bonded to the skin. They shoot a layer of wet chop - from the
chopper gun - then push the dry core into the chop. There is no time to
vacuum bag. No way to know if there is actually full contact between skin
and core. No boat manufacturer does an ultrasound on their hulls to check
for voids before they deliver a hull. They have no way to do a quality
control inspection on a female molded foam cored hull or deck. It's all up
to the diligence of the laminating crew. I have supervised laminating crews
at two manufacturers. You know they pay those guys about a buck over
minimum wage . . . some of them can even read, but usually HR reads the MSDS
to them to keep OSHA off their backs. It ain't skilled labor - that's the
carpenters and mechanics.
I have been there and watched it happen at several manufacturing sites. At
least in a one off method, you can see that the skin is properly adhered to
the core. And I agree with you Jacques, for an armature, it can make for an
easier job in the construction process, and you can see that the skin is
properly bonded to the core. For the well educated armature it is a viable
method of construction. However, as you make the skins thinner, so that the
boat is lighter, you give up impact resistance. I guess if you built a boat
in Airex, epoxy, and Kevlar or carbon fiber, you could eliminate the impact
resistance issue. Then you would have a very strong, stiff, EXPENSIVE boat!
Oh yes, and don't forget to paint it WHITE, because if it is a dark color,
it will tend to heat up and get soft in the summer sun. Of course, the
inner skin will stay hard because it is insulated by a layer of closed cell
foam.
It seems that the people that survey and repair boats have a different
perspective than those that design and sell. Jacques, my experience
repairing (attempting to effect permanent repairs) on Airex cored hulls is
not "unsubstantiated rumor" - it is personal, hands-on experience. Maybe
the foam wasn't Airex. The manufacturer said that it was Airex - maybe they
lied. Maybe my Chemical Oceanography professor lied when he told me that
"Water is the universal solvent and NOTHING is truly WATERPROOF." Maybe if
I submerged a piece of Airex foam in seawater for six months, and then
checked it for a change in weight, it would weigh the same as it did before
. . . whoops I don't want to start another unsubstantiated rumor. True, the
rudders I have repaired were filled with expanding two-part foam. But that
expanding foam is also "closed cell." Airex is made with an expanding
process - it's plastic bubbles that are created by expanding inert gas.
Rumor has it that my experience is irrelevant, and I don't work in the
marine industry anymore, haven't for over 15 years. Maybe the laws of
physics and chemistry have changed since then.
Tom Bloomer
JACQUES_MERTENS
foam is one of those. You can do a good job without vacuum bagging with
Airex or CoreCell.
Also, amateurs almost always do a much better job than professionals. I have
worked as manager or engineer for several major boatbuilders and with some
exceptions, I saw very poor practice in most shops. The exceptions that I
know are Pursuit (S2 Yachts) and Cigarette --> quality.
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
Steven Shelikoff <shel...@averstar.com> wrote in message
news:38C8048C...@averstar.com...
Harry Krause
>
> Agree: it is important to specify a somewhat forgiving material but cored
> foam is one of those. You can do a good job without vacuum bagging with
> Airex or CoreCell.
> Also, amateurs almost always do a much better job than professionals.
Good grief, Jacques...do you really believe that balderdash?
--
Harry Krause
------------
I'm in mourning. My pet rock died last week.
Ed
Hey Harry,
Seems that 'Jacques', grief aside, mite just " do that" ...
which, speaking of "OJT", ... leaves me naught for choice of "Pres" ...
Sorry `bout yer rock, Harry ... I can send you one from my backyard.
Ed
Steven Shelikoff
>
> JACQUES_MERTENS wrote:
> >
> > Agree: it is important to specify a somewhat forgiving material but cored
> > foam is one of those. You can do a good job without vacuum bagging with
> > Airex or CoreCell.
> > Also, amateurs almost always do a much better job than professionals.
>
> Good grief, Jacques...do you really believe that balderdash?
I know what he's trying to say: that someone building their own boat is
more willing to put in the time and loving care than a professional on
an assembly line. But I just don't agree that the amateur will "almost
always" end up with a better boat. Now, if it were a professional
building his own boat...
Patrick Weaver
> Below the waterline? You're just repeating what that web site states but
if
> water goes through a polyester skin to get in a foam core, then all
> polyester boats should be sinking no?
>
depending on how well they are built. It's the same old tired argument.
Epoxy is better, it absorbs less water. Yes, marginally, but whether it
makes a difference depends on use, construction practices, the intended
lifetime of the boat, and if at any point you expect the Coast Gaurd to fill
your boat full of bullet holes. Doing some heavy duty smuggling better use
Kevlar! Or better yet armor plate. The best bet is to look for similarly
constructed boats and ask actual owners\builders about problems. Remember
Unless the majority of owners reports agree anecdotal evidence requires
further study. Exactly why did the construction method fail? What materials
exactly were used? Was it the result of poor workmanship? Wrong/poor
material for the purpose? Remember you get what you pay for (mostly) but
more expensive is not always going to give you a more usable boat. The only
requirement is that the finished product be suitable for *your* intended
use. Experts will make claims and counter claims until you are completely
confused but you notice very few of them provide any meaningful data or
clear examples in plain contexts. It all matters little when some yutz rams
a jetski into your waterline. No genralization is worth a damn including
this one. I think it was Robert Heinlein that said that but I may be wrong.
Don't spend huge amounts of time and money on marginal differences when they
don't matter. I'm building my boat (a dinghy) with plywood and housepaint.
You can tell me I'm doing it wrong until you are all blue in the face but
remember I know some people that own jetski's....................
I'm done ranting. I feel much better now, don't you?
P.S. Jacques even quality closed cell foam does absorb water. Enough to
matter if properly applied and coated with (insert appropriate resin of your
choice)? Not enough to matter in our lifetime. Or our childrens'.
JACQUES_MERTENS
support of amateurs building foam and balsa cored boats from our plans
(early 70's) and later I worked as manager of US boatbuilders with several
hundred workers: in general, amateurs do a better job.
--
Jacques Mertens
Boat Plans OnLine
http://www.bateau.com
Steven Shelikoff <shel...@averstar.com> wrote in message
news:38C91F16...@averstar.com...
JACQUES_MERTENS
> matter if properly applied and coated with (insert appropriate resin of
your
> choice)? Not enough to matter in our lifetime. Or our childrens'.
>
Kant (I despise him) about absolutes. When I say that it does not absorb
water, it implies "not in any way relevant to our purpose".
Patrick Weaver <zymur...@citlink.com> wrote in message
news:Tcay4.82$g67....@news-west.eli.net...
>
> > Below the waterline? You're just repeating what that web site states but
> if
> > water goes through a polyester skin to get in a foam core, then all
> > polyester boats should be sinking no?
> >
> > --
> > Jacques Mertens
> > Boat Plans OnLine
> > http://www.bateau.com
> >
Joe Della Barba
<JACQUES...@email.msn.com> wrote:
>We can go on forever about that but my first job in this industry was tech.
>support of amateurs building foam and balsa cored boats from our plans
>(early 70's) and later I worked as manager of US boatbuilders with several
>hundred workers: in general, amateurs do a better job.
>
>--
>Jacques Mertens
>Boat Plans OnLine
>http://www.bateau.com
>
>
I might agree. Some jobs just are not worth doing for money, but if it
is YOUR boat and YOUR life you will pay attention.
Joe
Steven Shelikoff
I would definitely agree that the amateur building his own boat would
*try* to do a better job and put in the hours necessary. But some of
these tasks (fiberglass layup, working with foam) are done better by
skilled workers with experience. When buying a homebuilt boat, you'll
probably see a lot more variability in quality. Some may be great and
others may be junk. Same thing holds true for many other products, from
cars and planes to Heathkit electronic equipment.
Nick Nelissen
I have a bit of an interest in this (see my other thread re
polyurethane). I have to agree that good fiberglass layup is a skill. I
worked in the polyurethane industry where the molds were made from
epoxy-fiberglass. The guy who did the gelcoat and initial layup was a
true master. The pressures involved are enourmous and any slight air
pocket or weak part will end up as a flaw in the mold as the gelcoat
gives way.
The problem is that this skill must be learned. If your boat was made by
the master then you are in luck, if made by the apprentice then you may
have trouble.
That said, as a beginner I will certainly practice my layup skills on
test samples until I get it right. I did get to put layers 3 and onwards
onto those molds, probably because they would cause less damage if they
were faulty. Not really my job (design,mechanics and electrical) in the
place, but in a small factory you need to be a jack of all trades. I
suppose others would just start laying up their hull and by the time
they get to the outer layers, would have mastered it. Unfortunatly it's
the inner layer that bonds to the foam and that goes on first.
Nick