I do have some stuff somewhat related to this. I redid the bows of my Tobago35 in 2003.
As I understand it, the boat had some trouble while spending 6 years in Martinique
. Those big waves caused some flexing at the bows, as they dove and resurfaced, and caused 5-6 feet of cracking up and down the bows. The owner's answer was to put a bulkhead at the bows, about 14 inches from the bow, and for the full height, just allowing draining and access to the deck hardware
bolts at the top. Proper and well constructed solution to the flexing. However, he then just polyfilled the cracks and splashed on some gelcoat
I noticed the cracks, and started to sand down. What a mess. I had to go 3/8" deep, and in places the crack and filler was the same 3/8" wide, with black glass on each side. I rebuilt it out, but with only regular polyester resin and glass. I didn't have a good eye nor the patience to try to get the "out of the mold" shape, however.
I can provide the pictures, if you like. Working on the bottom required some "MacGuiver" skills, if you know what I mean.
The boats are constructed using isophthalic polyester resins; such that they apparently do not fear moisture uptake and damage. Unsure how to protect my little repair. Probably will have to redo it with epoxy
or better resins at some point.