When we surveyed Sparkle Plenty in mid September 2001, we
found that patches of paint were not adhering to the bottom. The
previous owner speculated that the problem was due to a poor
bond with an old barrier coat. My surveyor and I both thought
this a reasonable assumption. We were all wrong.
And I was most at fault because I failed to learn from the survey of a
previous vessel with a questionable bottom. During that survey,
we were dealing with a bottom that had not dried out after being out of the
water for six months. Using moister meter readings, the surveyor drew a two
foot high band of wetness from the bow to the stern along both sides of the
bottom. I consulted with Osprey Marine Composites, a well regarded bottom
repair facility in Deale, MD. They recommended a laminate analysis to
determine the condition of the wet bottom and perhaps learn why it wasn't
drying out. At this point I had the vessel under contract based on a
satisfactory survey. The owner agreed to the laminate analysis with the
stipulation that I bare the cost ($150) and make the bottom sound. The
procedure involved grinding two three inch circular sections down through
the bottom, one fore and one aft. When the Osprey technician ground the aft
section, we found that the hull was balsa cored and the honeycombed core
material was wet. When he ground the fore section, we found that the core
was wet and also delaminated from its outer fiberglass layer. It was only a
guess as to how many of these delaminated areas were present elsewhere in
the wet bottom. Based on this test, I withdrew my offer and began a
search for another vessel.
Back to the Sparkle Plenty survey. SP was in the water and hauled
out for the survey so there was no time for the bottom to dry. On
inspection, the bottom showed no blisters. Since the gel coat had been
peeled away during an earlier bottom job, there was no chemistry left to
form blisters. Blisters form when water penetrates the gel coat. However,
there were those patches of missing bottom paint. At his point, I should
have opted for a laminate analysis on one or two of those patches.
Flash forward to January 2002. Sparkle Plenty has been up on the
hard since early December and is now resting in an environmentally
controlled soda blasting pit operated by Osprey Marine Composites at
Harrington Harbour North Marina in Deale, MD. I've decided to have the old
bottom paint soda blasted off, then the old barrier coat renewed and
properly bonded to new bottom paint. This should provide a much fairer
bottom and eliminate the falling patches of bottom paint. Wrong.
As the technician begins soda blasting the hull, it quickly becomes
apparent that old barrier coat is not in good shape. It's
extremely thin and beneath it is a layer of fiberglass mat that is dry and
porous. During the old bottom job shows the original gel coat had been
peeled away and the underlying raw glass faired up with a new layer mat.
Unfortunately, this layer was not adequately impregnated with resin. Over
time, the mat absorbed water which froze and thawed causing several long,
deep voids in the solid glass hull. Fortunately, the glass is one to two
inches thick and the hull's structure has not been compromised.
After consulting with Osprey, they recommend peeling the bottom to
remove the old fiberglass mat, covering with new mat and resin, then faring
the hull. Finally they will coat the hull with 5 mils of vinylester
putty for an impermeable barrier coat to which they will bond a coat of
Petit Trinidad (hard) bottom paint. The bottom line: I'm going to need a
complete bottom job -- even though the bottom is blister free.