GRP repair

[BrendanS]

Recently discovered that my GRP sportsboat has a crack in the hull below the waterline..near bottom, about 4ft forward of transom, running widthwise across hull for about 1 inch. Seems to follow an internal stringer (judging by knocking around the area), and is located on the bottom most 'spray rail' if that is the correct term. Stress cracks in gel coat on same location on opposite side of boat.

Dealers have been great - asked for digital photos, which they sent off to manufacturers in US, who responded within 24 hours asking dealer to get quotes for repair under manufacturers lifetime hull warranty.

Local repairer with 30 odd years experience has taken a look at hull today, and asked for a surveyor to get involved. He doesn't believe at first look, that it will be possible to make repair to original strength, though he can beef up things internally, as original chemical bonding when the hull was being laid can't be reproduced, and it may crack again after repair.

Anyone know 1) what the likelihood of a decent repair is, and 2) what the likely outcome is if repairer and surveyor think that a safe or enduring repair cannot be effected?

Thanks,

Brendan

 

[BarryH]

I would go with the repairer. He has doubts and has asked for survey to see full extent of damage and causes. Altho if his had 30 years in the trade, you would think that he would be able to decide wether a full repair can be made. Do you know what caused the crack in the first place, and how long its been there? I dont think any repair to a "glass" hull will ever be a stong as the original structure. The one saving grace is that the thing is still under warranty.

OK, to hell with it. Unbolt it and we'll use it as an anchor!

 

[30boat]

With fiberglass construction you can make a repair as strong as you need it to be especially if you use epoxy.It is true that the primary bond is the strongest possible one but just look at some of the Kelsall catamarans built almost exclusively with secondary bonds.I wouldn't be overly influenced by outside opinions and get the repair done.

 

[BrendanS]

Not my decision whether or not to go with survey at moment...totally in hands of dealer and manufacturer. Just interested in what the options are, and if a safe repair cannot be made, what is the likely outcome.

As to cause ....well it's kept on a dry rack (21ft'er) and while the crack wasn't noticed when the yard forklifted it out of the water after last trip, they noticed on the way in a couple of weeks later. Suspect that the crack didn't show when they took it out as the crack was clean, and wouldn't have been noticeable. After a few weeks sitting there, dirty water seeped out and made the crack black.

Suspect stress crack - it follows a stringer - though whether that has been influenced by water in that part of the hull due to previous problems I don't know Dealer had it for a month earlier this year, as water was getting into inside cuddy, and accumulating to several inches after every trip, and had no way to drain to the engine bilge where the bilge pump is. They had an engineer over from the US, who did a fantastic job of fixing the problem, but I wonder if there was water getting into the rear hull to the side of the engine bay, where again there is no drainage, as no water is supposed to get there. Wooden encapsulated stringer as far as I know. Lot of guessing here. Really don't know.