| Putting cores in boat
structures is now THE thing to do. Almost all late model boats we run
into have more and more coring. Decks, hull sides, bottoms. Which leads
me to wonder if boat builders know why they're doing this and what the
potential consequences for their future reputation is. Builders are coring everything because their cost analysis suggests
that using a lot of foam is cheaper than very high cost plastic resin,
particularly the vinylesters and orthos that are needed on bottoms to
avoid blistering. After all, cores make structures stronger, right?
Only if you know what you're doing, and what we've been seeing lately
strongly suggests that a lot of builders don't. They think they do,
they'll tell you that they do, but their products say otherwise. For
example, we all know that if you allow water to get into a balsa core,
you end up with a big problem. The solution: use foam instead of balsa.
It's impervious to water. Or at least they think it is.
The fact is that most polyester based foams are not impervious to
water any more than orthopthalic polyester resins are (the resin type
most prone to blistering). When immersed in water long term, most poly
foams will break down and the styrene separates out in the same manner
as hull blistering. Most of the wet foam cores we've looked at reek of
styrene just like blister fluid does.
In our view, the jury is still out on where this widespread use of
foams cores is leading us, mainly because extensive use of the material
hasn't been around long enough for us to get a good handle on how well
these structures will hold up. One thing we do know for sure, and this
is that builders are taking a much more cavalier attitude toward the way
they handle foam cored structures.
We've assembled a collection of photos here to evidence our point
that builders do not seem to think that they have to handle these
structures with any high degree of care. Here we see builders drilling
holes and running bolts and fasteners into cores with no concern
whatsoever for water leakage. No caulking necessary.
The photo at left is the underside of a cockpit deck showing
the bolts used to attach cockpit seating modules. Virtually no caulking
was used and the bolts are obviously leaking water not only into the
core, but right through the deck. The red arrow at left points to where
they simply drilled a hole through the cored deck to run a wire for foot
lights. This boat is less than two years old, so whatever the effects of
water into the core are as yet unknown.
If this cavalier handling of cores is bad, the next example shows
that it can get a lot worse. The "it" in this case is the
builders' degree of knowledge (or worse, his lack of concern). The
majority of cored structures we are seeing on new boats has only ONE
layer of glass laminate on the inside or underside of the structure, be
it a hull, deck, whatever. Needless to say that when you attach a load
bearing piece of hardware as we exemplified in the photo below, this
isn't going to work out so well.
This, believe it or not, is a bow cleat bolted directly through a
foam cored deck with only washers backing it up on the under side.
Obviously, it would only take a modest load on these cleats to end up
crushing the core.
The left photo shows how it should be done, but this
takes a little bit of extra work and planning. Notice here that there is
no core in way of the area in which the cleat is mounted. If there is no
core, then no water can get into the core, nor is it possible for a
heavy load to crush the non existent core. Note also the aluminum back
up plate under the cleat, even though it's attached to solid glass.
What is shown here is the difference between a boat builder that
knows what he's doing (or cares) and one that doesn't.
In yet another instance, a dealer installs an anchor winch. All he
sees as being necessary is to drill a few holes and bolt it on --
through a foam cored deck. Just about anyone can figure that a winch is
going to be very heavily loaded, but not this dealer. He just bolts it
on with a few small washers under the nuts, and doesn't even bother to
seal up the large hawse hole he drilled through the deck. This is a new
installation depicted here, so the problem is yet to manifest itself.
The next example comes from a boat that is not new, and the extent of
the problem of water into the core has become very obvious. Here's
another hole in a foam cored deck that allows a huge amount of water to
come through, as you can see by the wetness. While we do not know what
the black gook is weeping out of that hole, we can only presume that
there is some sort of water reaction with the material.
And then there is the case of the new $750,000 fifty foot cruiser by
a popular builder. This boat has a cored bottom, but the buyer wisely
hired us to check it out before he handed over his money. The photos
below show what we found.
Shown above is the bilge area where two 1/4" holes were drilled
through the inner laminate on the bottom of the cored hull. Why these
holes were here is anyone's guess, but had we not found them, the core
of this hull would surely have filled up with water.
The only good news to come of things like this is that by
getting a new boat thoroughly checked out prior to purchase, most
such problems can be found and corrected. Our new boat inspection
program is designed to find an locate such deficiencies so that the
problems can be fixed at the builder's expense, not yours, and so that
you won't be facing a big surprise when it comes time to sell your boat
when a surveyor comes along and says. "Mr. Boatowner, you have a
problem."
Related Reading:
Dealer Service Qualifications at www.docksidereports.com
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