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The
roots of fiberglass boat building go all the way back to the 1930's
when, so far as I know, the first reinforced plastic boat was built
by Gar Wood in 1936. Were it not for the Depression and W.W.II,
production fiberglass boat building probably would have been initiated
in the 1940's but, as it was, really began in earnest in 1960 with
the pioneers of fiberglass boat building, Bertram, Hatteras and
Hinckley. In the mid to late 50's, there were companies such as
Glastron and MFG (Molded Fiberglass Products) who were turning out
chopper gun boats by the thousands, which tended to fall apart in
equal numbers. These were not pioneers, but simply companies taking
advantage of a new technology to make money, so I'm not going to
give them any credit as pioneers. Everyone knew that chopper gun
stuff was no good.
The work of BH&H was quickly recognized for
the revolution that it was and by 1970 the number of wood boats
being built dropped off to a small fraction of total production.
Chris Craft, the lion of the industry, started making fiberglass
cabin parts as early as 1959, and by 1965 the majority of its production
was in glass. When Chris Craft switched over, everyone followed.
The miracle fiberglass had arrived and boat building took off like
a rocket. No more cutting and assembly of 2,000 wooden parts. Throw
some stuff in a mold and presto! Instant boat.
Well, not exactly, but an apt comparison to the
work involved in creating a wood boat. And while it cut labor costs
dramatically, the cost of materials and tooling more than offset
the labor savings, and the price of plastic boats went up. But no
one saw it as a price too high to pay for a boat that didn't rot,
or have to be sanded and painted every year. No, fiberglass really
was a miracle material, as it remains to this day almost forty years
later.
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| Knowledge and expertise are not a requirement
for the boat building trade. Here a builder tries to foam
core a 1/2" thick flying bridge coaming. The cored laminate
is left exposed, merely covered over with gelcoat. What made
the builder think this was a suitable place for a core? Another
example of the use of materials employed with an utter lack
of even the most rudimentary understanding of the use of the
material. To make matters worse, he then mounts tower legs
to the very same structure you see here and it collapses.
Educated children could do better than this. |
An even more important consideration was the calibre
of skill involved in wood boat building. For all their parts and
complexity, this was equaled by a tremendously skilled work force.
The guys who built these things were not hammer and nails carpenters,
but men from the cabinet making, and often the old wooden aircraft
industry, with a lot of training under their belts. For this reason,
wood boat construction errors were very rare. They understood not
only fine wood work, but high production work as well. The situation
with glass boat building is the exact opposite.
The problem for glass boats was that the cost of
materials kept going up, while the market keeps demanding cheaper
boats. Needless to say, something has to give, and it's not going
to be the volume of boat sales because people can't afford well
made boats. Oh, no. For a builder to stay in business, he has to
turn out a product that people can afford to buy. If it's a piece
of junk, like MFG and Glastron turned out in the early days, so
be it. People will buy anything that they have no knowledge of.
Early Engineering In 1961 nobody
knew much about fiberglass. The Navy had been doing some work with
it ever since the end of W.W.II. At first they made life boats with
it. In fact, even John VanHoboken, Design Chief at Chris Craft didn't
know much, and I'll tell you how I know that. My father purchased
a 1965 Chris Craft 38' Commander. When we drilled a hole in the
bottom to install a transducer, it was OVER one inch thick. It was
so heavy, we jokingly said that it wouldn't get out of its own way.
Only four years later, that very same model was laid up right down
to the failure point. The first boats that were over an inch thick,
were now around 1/4" and they were breaking. That didn't last
long because they just increased the laminate a few notches.
The point here is that what we had here was in-product
testing, e.g. using the product as R&D. And unfortunately, we
still have a lot of that going on today. Back then, it wasn't much
of a problem because a solid laminate is a pretty simple thing.
Just as a carpenter with no engineering training can build a perfectly
good house because he "knows" wood, so could a boat builder
build a good boat by "knowing" how much to use here, how
much there, and so on. But that did not last long, for things were
going to change in a big way. Seat of the pants engineering would
no longer work with the introduction of a wide variety of new materials
or variations thereof. Instead of having just a few basic materials
to have knowledge of, the number of possibilities was about to multiply
greatly.
Along came a guy in the balsa wood business, the
founder of Baltec. His business was not doing well because the applications
for balsa wood, mainly the aircraft industry, was declining, so
he was diligently searching for new markets. Then he discovered
the newly formed Hatteras Yachts and the use of balsa as a core
material was born. To this very day, a majority of boats are still
being built with balsa cores.
The need for cores was quickly recognized for use
in large flat expanses of laminate such as decks and house tops.
Fiberglass laminate was too heavy to use it in the thickness required
to make decks solid enough that they didn't bend or deflect. That's
because reinforced plastic is a bit too flexible. Very strong, but
it does bend. By sandwiching end grain cut balsa between two
layers of fiberglass, this creates the effects of a truss and significantly
stiffens up large flat panels. It was a perfect solution for floppy
decks but for one thing: balsa is wood, and it will absorb a lot
of water. As long as you design the structure right, with no fasteners
going through the core, water won't get into it and it won't be
a problem.
That notion is well and good but for one
thing: Boat builders understood this, but no one else did. So people
went merrily on their way drilling their decks and house tops full
of holes to mount things. Water then got into the core and 10, 15
or 20 years later we're back to floppy decks again because the core
eventually rotted. Next, they started using balsa to stiffen up
hull sides because builders realized that they could cut some material
out, ostensibly save a little money on thinner laminates. A few
builders decided to go whole hog and use balsa for the entire hull,
with disastrous results. One cannot use balsa underwater and not
expect it fill up with water, which is what they all did. Ergo,
the rule in boat building became: core only to the waterline.
This worked out pretty well because people generally
don't go drilling the hull sides full of holes like they do the
decks and house tops. Of course there were always a few, but by
and large, balsa coring in hulls sides worked out just fine. Made
the boat much quieter inside, too.
Then came Sputnik, Yuri Gagarin, and John Kennedy
who wouldn't be bested at anything (Not the least of which were
the women of his extramarital affairs. Democrats can't understand
why people make such a big deal over Clinton and Monica. Kennedy
had Marylin Monroe, for gosh sakes! Quite a difference there. Who
could blame anyone for boffing MM?) and we're off to the moon. Estimates
were that it cost a million dollars a pound to put something in
space, so we needed some new light materials. The techies in the
aerospace industry had their eye on reinforced plastics and began
diddling around with it. The more they diddled, the more they liked
it. Glass fiber wasn't strong enough, but they knew that DuPont
had come up with a new fiber called Kevlar, and a lot of work was
being done with carbon fiber.
Ultimately, the aerospace industry revolutionized
reinforced plastics, now called "composites." They were
making all kinds of ultra high strength, but very light parts from
these new concoctions, and naturally it had to catch the eye of
boat builders. Cored structures were increasingly being used for
interior components such as bulkheads and panels, particularly in
commercial aviation. Boat builders wondered how they could use these
materials in their products, but there were several giant obstacles
in their way. First, these new materials were very expensive and,
secondly, you can't employ unskilled, immigrant labor to utilize
them. The complexity involved in the use of this stuff was tremendous.
That did not stop them from trying, of course.
Because of the high cost and degree of skill required
in application, there wasn't and probably never will be an application
for them in boat building which, after all, is a rather low tech,
low capital business. They're not exactly General Dynamics or Martin
Marietta, mind you. Wise builders stayed away from high tech, seeing
nothing but trouble in it. But a bunch of small builders, who could
least afford to do so, leaped in where wiser men feared to tread.
And so we had our first foam and honeycomb cored boat hulls that
ultimately fell apart simply because they were using a new material
about which they knew almost nothing. But the stuff had lots of
fancy names like Divinycell, Termanto, Airex and Kledgecell, and
it was easy enough to sell the public that the second coming of
the messiah had finally occurred.
A lot of bankruptcies followed thereafter, and
foam cores were tarred with a bad reputation. In fact, all cores
were tarnished, even though most people were buying balsa cored
boats and not even knowing it. People said, "No way I'd own
a cored boat," oblivious to the fact that they already owned
one.
Economic conditions continued to apply a great
deal of pressure on builders to reduce costs and increase profits.
The 1989 recession wiped out over half the U.S. industry, and most
survivors concluded that their boats were just too expensive to
produce. Prices had tripled in preceding decade-and-a-half, although
inflation running as high as 18% accounted for most of this. Still,
the boat that cost $30k in 1972 cost $100k in 1985 and sales were
dropping through the floor.
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| A graphic example of a major laminating
error. The white stuff is the bonding putty that is supposed
to adhere the core to the fiberglass. As you can see, it bonds
neither. Here the core does not even come in contact with
the adhesive and the laminators have no way of knowing whether
it does or not. The construction process of this yacht was
nothing more than guesswork. A very heavy price to pay on
a 60' yacht. |
As we all know, the cost of boats never did go
down, but neither does the cost of much of anything. It remained
a fact of life that boats were built by hand, and no mater the cost
of materials, labor is uncontrollable. Unlike most other industries,
boat building was not amenable to automation. The industry could
not be consolidated into the "Big Three" as the auto industry
was (although many tried), and no builder would ever be able to
capitalize a major plant automation. Those that spend a lot of money
on plant only lived to regret it when they found themselves heavily
in debt when the next recession inevitably arrived. There was no
getting around the fact that fiberglass boat building was sticky,
gooey work that had to be done by humans.
So all that was left to do was to keep working
to cut the amount of materials and the amount of labor required
to employ them. That meant using less material in more simplified
operations. The application of high tech materials and methods from
aerospace was anathema to boat building. High tech meant more costly,
more labor intensive materials. Exactly the opposite of what they
needed.
As with everything else we buy, technology plays
as much a role in marketing as it does in the actual creation of
the product. Sometimes more, as in the case of boats. If you grab
a handful of brochures at the local boat show, it is immediately
apparent that high tech is a major selling point. It's what people
want to hear, never mind they don't understand its meaning. It sounds
good, so that's what they're going to say. Hard to blame the marketing
people for that. You succeed by giving the customers what they want.
Or at least create the allusion.
Of course, a lot builders aren't going to
just create the allusion, but actually try to live up to people's
expectations of the miracles of technology. Yes, builders and designers
(at least most of them) understand this, but we, the public, have
them in a box. They either produce miracles or else.
And here's where the trouble begins. Boat building
already had its miracle, it was called molded fiberglass. Like the
modern radial tire, it's been around a long time, and no one has
had much success in improving it, despite all the hype. Tires have
been much the same for over 30 years with no significant improvements
at all. Despite endless advertising to the contrary, your tires
behave the same as they always have. They last about as long as
ever, and they still go flat when you run over a nail. It's hard
to accept the fact that some things are as good as they're going
to get, but it happens. If you think about, there are a lot of things
that can't be improved. They are already perfect.
Compare this with boat building. Have boats become
better, more reliable as a result of all this technology? No, they
haven't. In fact, they seem to be regressing toward the early days
of MFG and Glastron. Dispose-A-Boats. Good for ten years and grind
'em up. But the public cannot afford that, and so boat sales are
again declining at an alarming rate.
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| How would you like to have a boat made
of this stuff. Picked up out of a builder's shop who was coring
the hulls of 26 footers, it caught my attention because I
could crumble it between my fingers. |
Yesterday and Today The
simple fact is that the materials and methods used to build boats
in 1965 remain good enough to continue to be used today. 1965 technology
(if you can call it that) is perfectly suited to build good quality
boats to this day. In fact, most boats are still made with the same
basic materials, although the advertising has fooled you into believing
otherwise. The primary difference is that they are USING LESS
OF IT, and substituting cheaper materials for more expensive solid
laminates. Speaking of solid laminates, that's what I mean by 1965
technology.
When it comes to the use of core materials, they
are employed not, as was originally intended, to stiffen up flat
structures such as decks, but to replace more costly material with
less costly material. In essence, where there used to be solid laminate,
the space is now filled with air, because air is what most cores
are all about. It would be one thing if these cores were serving
to make structures stronger. Instead, they are being used as an
excuse to eliminate frames, to make unsupported spans of flat surfaces
even larger. It costs money to add frames: use a core and eliminate
the frames. In most cases what we end up with is not a structure
that is stronger, but weaker.
Typical examples of this are hull sides and decks.
The average entry level cruiser has a cored foredeck with virtually
no frames. Jump on it and it's like a trampoline. No problem, except
when you do jump on it, and that deck flexes, what is happening
is that the core is separating from the outer laminates. A cored
structure is designed not to bend, like a bridge. When you do bend
it, bad things happen, like the bridge or deck starts to fall down.
Much the same thing is going on with hull sides. Most small boats
don't use foam cores, but products like CoreMat, a material that
sort of looks like that absorbent material you find at the bottom
of meat packaging. It's a fibrous material with millions of little
holes or perforations through it. It would be great stuff except
for a couple of things.
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| Hurricane damaged boats give us a great
opportunity, not only to see how good layup workmanship is,
but how well materials perform under destructive testing.
This is a Grand Banks 46 for which more of the damage was
caused by poor workmanship than anything else. The box at
upper left shows where a material like coremat was used. I
just grabbed onto the outer laminate and tore it right
off with ease, in this and many other areas. The bonding strength
was EXTREMELY poor on both sides of the material. In the box
at right is a roving laminate that was not bonded AT ALL It
was a direct roving-to-roving laminate, which is an improper
laminating method. You can tell this by the shiny surface.
There were extensive areas like this throughout the hull.
This boat should not have had half the damage that it actually
sustained. |
First, it absorbs water like a sponge. Small boats
never had much of a blistering problem until products like this
came along. Now they blister just like Taiwan boats that are loaded
with chopped strand mat and blister like a banshee. Secondly, very
thin cores like these do not create a structural truss like a real
core does. Cores increase strength by separating the distance of
the load between the inner and outer skins. Think of the skins as
beams, and the core as columns. The effect is exactly the same as
a roof truss. But not when you use a thin sheet of this stuff. All
it does is replace strong material with weaker material.
Take a typical cruiser, use a core like this in
the house sides and then paint it black. Set it out in the Florida
or Texas or Alabama sun for a few years and watch what happens.
Ooooh! Weird! It buckles and cracks. Want to know why? Or do you
want to know why the builder didn't know what was going to happen?
Or did he care? Oh, no, he simply didn't know because he doesn't
employ any composite engineers. The material salesmen designed the
thing for him, so he's happy as a clam thinking he saved some money
and can now tout "high tech." What happened, of course,
is called heat distortion. Every place a laminate is held rigid,
like around a window frame with screws through it, the material
expands but is restrained by frame and fasteners. And so it does
the only thing it can do, it buckles and cracks.
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| Here's another photo of our Grand Banks,
1989 model, considered by many to be the premier of its class.
What you see here is an area on the hull side where I grabbed
ahold of some cracked laminate and just yanked it right off.
Total area size is about 10" x 24". There was absolutely
no bond here between these two layers of roving. At the very
center of photo, you can see where a few fibers managed to
stick. If they have this much trouble with major errors in
solid laminate hulls, imagine what it's like with cored hulls.
Any more questions why boats blister? |
Foam Cored Decks Foam might
seem like a great replacement for balsa, since it doesn't rot. But
that doesn't mean it won't deteriorate. It can and it does. By a
variety of means and methods. The problem I have with foam is this:
Balsa is balsa, and it doesn't come in 100 different formulations.
With balsa, you know exactly how it's going to behave under all
conditions. Not with foam. Try looking at a piece of foam and determining
what it is. No way. All you can do press your fingernail into it
and determine its density and compression strength. Or bend and
break it.
You already know a lot about foams because you
see lots of it used in packaging and insulation, so you know most
of it is not very durable stuff. In fact, put it out in the sun
for a couple of months and it will literally disappear. It evaporates.
Literally. Then pour some solvents on it. Go into your paint locker
and you'll find at least one that will dissolve it. Put it on the
ground and step on it. Crushes pretty easy, no? Work your fingernails
into it. Crumbles real nice, does it not? Now apply some heat to
it. Doesn't have to be much, just bring a match near. Try to burn
it with the match. Burns like crazy, right? Hot and fast. Now try
the same things with a piece of balsa. In virtually every category,
balsa out performs the foam. And when it comes to biodegrading (meaning
rot), in many cases the balsa will still outperform the foam. Balsa,
like teak, contains a toxin that fungi doesn't like. It doesn't
rot until that toxin leaches away.
Another Problem: Most foams used in boat building
have very low heat distortion values. Basic PVC foam Heat Distortion
Temperature is around 150 degrees. That's about the temperature
the white deck gets baking under the summer sun. Add some color
to the surface and temperatures will begin to soar. I have measured
black painted surfaces on boats as high s 237 degrees. That's why
you see foam cored boats with painted dark trim, or dark gelcoat
colors, that look like a checkerboard. Heat distortion is irreversible.
These foams will also begin to stretch or creep when heated, resulting
in the laminates loosing their design strength. Structures can actually
change shape. The HDT of balsa is 360 degrees.
Shear Strength: The shear strength of most
PVC foams is around 40-60 psi; some are much lower. Balsa
is 400 psi. Not much else to say about this.
Why on earth would anyone want to use a material
like this? But you know the answer already. Money. Do you really
want a boat made with this stuff? Or do you want a boat made with
a material that at least you know how it performs? The problem,
you see, is that we do not know the properties of whatever foam
is used in a boat. We may be able to determine that it is foam,
but that's all. Which of the endless varieties of it may be, we
have no idea, and so nothing can be said for how it will perform.
After all, performance is proved by application experience, but
if we have dozens of varieties of the material, who can keep score?
Surveying foam cored boats gives me the willies if only because
I don't know what's in there.
Foam Cored Hulls As I have
shown, foam and balsa do not behave the same in their specific structural
qualities. Balsa has a lot of advantages that foam does not. For
example, because of the exposed end grain, when you coat it with
resin, the wood cells suck up that resin via the capillary effect
and makes for an extraordinarily strong bond. It does not require
any special adhesives as many, if not most, foams do. All the laminator
does is press it right into a layer of wet resin, and if there's
enough resin there, it isn't ever going to come unstuck. We can't
say that for foam because the texture of foam is very coarse, and
it does not suck resin up into the cells because foam cells are
round, not tubular like balsa. The bond it makes to resin is so
weak as to be unacceptable. Therefore they have to use a thick paste-like
adhesive (shown in the top photo) that will press into the round
cells a little better. It's hard to see how the builder gets any
benefit from this because his labor cost has just gone up because
the laminators now have to fool around with this gunk, which also
costs more money. All this just to get the darn stuff to stick,
which they have a hard time doing. As you can see from the nearby
photo, it doesn't always work out as planned. Wouldn't it have been
easier and cheaper just to lay in a few more layers of fiberglass?
I think so.
Sloppy work is much to blame here, but so is the
complexity of the material. Would this have happened with balsa?
The answer is much less likely because they don't have to deal with
the extra material, the putty. The complexity of the process thus
becomes a major factor when you are dealing with low skill, low
wage workers. All this does is to serve to increase the potential
for error, something that the builder ought to be avoiding at all
costs. The cost of one faulty product can wipe out the savings from
any particular process across the board, rendering all benefits
null and void.
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| Lay up errors are hard to capture with
photography, but here is prime example of what one looks
like that is easy to discern. The checkered pattern here is
incomplete bonding of woven fiberglass fabric on a large sport
fisherman. This condition involves the entire hull. The hull
of this boat is irreparable and ultimately failed. The cause
of this is a result of a lack of supervision of the lay up
crew that did not follow proper procedures. |
There is that thing call the law of diminishing
returns. It states that the potential for error rises proportionately
to the complexity of an operation. Exemplified by the acronym KISS,
it is particularly applicable to human skills as opposed to automation.
Machines do not get distracted, forgetful or emotionally unstable;
people do. People make mistakes in proportion to the complexity
of the things they do because they are distracted or simply don't
care to do it right. Compounding the problem exponentially is that
most builders have little or no lay up supervision. They aren't
about to pay a salary for a supervisor to stand there and watch
their work. When errors occur, they usually go undetected.
Since I babble on endlessly about the disvirtue
of "price" boats, lets consider a moment the cost of a
supervisor. Say he's paid $30k per year. With benefits and social
security, the cost to the employer would be around $40k. If he supervises
40 boats per year (and that's a lot) he adds a cost of $1,000 per
boat, regardless of the value of the boat. If the wholesale
price of the boat is $15k, he's adding 6.6% to the cost at wholesale,
and probably 10% at retail. Does this paint a clear picture of the
nature of the beast? Will you pay an extra 10% to ensure that your
hull won't fall apart? No, you won't, and that is the reason why
there is no supervisor, no quality control, no nothing. Oh, yes,
they have a guy that makes sure that the boat LOOKS good, but not
one that makes sure that it IS GOOD.
So it is that we end up with problems like this
in foam cored boats that almost never appeared with balsa cored
boats. Instead of making a boat better, it made it worse. Does this
mean that foam is not a good material? Well, some are, many aren't,
but our problem in answering that question stems from a lack
of knowledge created by the large variety of foams produced and
used. A majority of production builders still use balsa, and
of those who do use foam, all but a few only use it in decks and
superstructure. The most prominent use of foam comes from custom
and semicustom small shops where owner involvement and the degree
of control is very high.
Should Hulls Be Cored Below Waterline?
I don't hesitate for a moment in saying no. Not with any kind of
material. The risk is too high that something will go wrong, mistakes
either by the builder, the owners of the boat, or someone working
on it. We all know that it's hard enough to keep the superstructure
of the boat from leaking, but to keep water out of a core below
the water line may nigh well be impossible. Fiberglass is known
to be water absorbent enough as it is without adding more risk to
the mix. To do it right requires a very high degree of care which
can ultimately be compromised by something as seemingly innocent
as running a screw through the laminate somewhere in the bilge.
it's just too easy to make a mistake.
The other problem with coring a bottom has to do
with the inability to calculate and estimate stress on complex shapes.
It's easy enough to calculate stress on a flat panel, but change
the contours of that panel, introduce the factors imposed by human
error, and any benefit that might have been obtained by coring the
bottom is long lost. The risk of error multiplies exponentially,
far beyond anything that is suitable for high production building.
The smaller the boat, the more true this is due to the scale and
economic factors. It's one thing to core a 110 footer that costs
8 million, something else again for a boat that sells for $100k
or so. The fact that the economic viability is not there for small
boats translates as the builder cutting corners to turn a profit
with a process he shouldn't be using.
| To give you an idea of how high tech materials
and complexity issues cause problems that bite the boat owner
in the butt, here are some quotes from Composites Fabrication
Magazine, Sept., 1998: The Conflict Between Cosmetics
and Structural Performance of Laminates, by Rob Schofield,
Naval Architect. Referring to a commonly used resin, DCDP:
"A large number of cracked parts appeared in the
late 1980's and still occur today, for laminates made with
DCPD resins."
"A large number of cases of delaminations and
debonded framing have also appeared for parts made with
DCPD resins, with the attendant claims against fabricators."
"The second problem of the DCPD resin blends is
the fact that secondary bonds are difficult to achieve,
such as for tabbing, framing, and interrupted-sequence laminate
groups."
"Blistering will generally occur with filled resin
systems (gel coat) exposed to the marine environment."
Also by Mr. Schofield in a different article:
"Straight PCV foam cores have a very low Heat
Distortion Temperature, and structures built with it should
not be left out in the sun. Things improve a bit as
we move into the rigid PVC foams [Most widely used in boat
building, D.P.], but not by much . . . balsa does phenomenally
well as a high temperature core."
This is but a miniscule sampling of the technical
problems of ordinary boat building as discussed by the experts,
published in a trade magazine. Looking at our Grand Banks
photos, it is easy enough to see that this is exactly what
Mr. Schofield is talking about. Bond failure due to resin
shrinkage. Here's a few more:
Mr. Schofield in Proper Evaluation of New Core Materials,
same publication, July, 1998:
"Materials technology is changing at a blurring
rate."
"Advertising brochures for the majority of these
materials are full of "information", but the important
core properties . . . . are frequently missing."
"In many instances, a fabricator will attempt
to try out one of these new cores without having the proper
evaluation information. In such a case, the design of products
incorporating the new material is based on an educated
guess . . . [emphasis mine] . . . this approach
often ends in failure and unfair 'blackballing' of the material."
"Relatively brittle foams, such as polyurethane,
particularly suffer from short fatigue lives."
"What may not be so obvious is the long term effect
of water or fluid percolation through the core over time."
|
All of which means that you run a big risk in buying
a cored hull when you could easily avoid that risk by buying one
that's not. Could the reasoning be more simple than this?
What I have described to you here is a crude approximation
of the problem. In truth, it's a lot worse than that, because of
the large number of new versions of the same materials. The dozens
upon dozens of variations of glass fabric is just one example. The
point here is that anyone who wants to learn all there is to learn
quickly discovers it's enough to fill a four year university course
of study and then some. And now we have all these people out there
building boats who do not have that training. Nor many of the people
designing them. No longer is it even possible to experiment with
materials in the product because no one could build enough boats
to cover all possibilities!
After reading this, you may be surprised that this
is not a treatise on core materials, but mainly about the application
of the material in the lay up process. You probably don't give a
hoot what the builder's problems are, but you need to understand
them if you are going to understand why there are lemons and turkeys,
and how to avoid buying one. If you don't know this, then you'll
find yourself lending a sympathetic, perhaps even eager ear to the
alluring claims of technology.
But technology is not the problem; it's the application
of it. It is good for some things, but not others. Most of the problems
are rooted in the human element of construction, just as it is with
a solid laminate. The fact is that a very large percentage of problems
with fiberglass boats, cored or otherwise, stem from the quality
of the lay up process compromised by complexity induced errors.
The rest are due to design and selection of materials, with faulty
design leading the pack as the basis for structural failures. Which
basically means that boat building is a low tech but complicated
business that, in order to reduce errors, needs to be kept
as simple as possible.
Anyone who has a house full of digital appliances
these days -- and who doesn't -- can understand how complexity renders
many products worthless. Something simpler is usually better than
something complex, though at first something with a hundred buttons
on it attracts us. Just love to push all those buttons. Until
we discover that 84 of them are there only to confuse you. This
principle is not readily apparent in boat construction, except when
it becomes time to call your lawyer. Now that you know, this should
never happen.
Related reading:
Cored
Hull Bottoms: The Final Word - Posted
July 12, 2001
Sea Ray and
Balsa Core Bottoms - Posted November 20, 2002
Posted October 31, 1998
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