gelcoat cracks at waterline

nodders · #1 (**permalink**) 11-20-2011

My new boat (a 28 Sirius sloop, 1983) is out of the water and I gave the hull a good lookover. I noticed there is a little bit of blistering and a fair number of cracks in the gelcoat along most of the hull within 1 inch of the waterline (a long strip). It is obvious that the previous owner made some rather sloppy repairs in this area as well. "repaired" areas are about the size of a dime. I am thinking of scraping/sanding this whole strip down, filling with epoxy and then covering with bottom paint. Any thoughts or recommendations on this?

I will try to post a picture but may not have enough posts to do so....here goes...

Well, that didn`t work very well!

mitiempo · #2 (**permalink**) 11-20-2011

Dave, here's your pic - it sort of worked.

overbored · #3 (**permalink**) 11-20-2011

Looks like the area above the waterline has been sitting below the water.

nodders · #4 (**permalink**) 12-08-2011

didn't get much response and am starting to worry about this repair (I do that when i can't actually start the repair). I am thinking of using a scraper to remove the cracked material which is found only in 1 inch above the waterline...then using an epoxy filler to repair the areas from which I have removed material. Next would be to raise the water line an inch or so, so the repaired area is actually covered in bottom paint.

Any thoughts on this process? I find it very odd that the surveyor (we just bought the boat this summer) didn't notice anything askew and he had it our of the water.

celenoglu · #5 (**permalink**) 12-08-2011

The posted image is not very clear. You can open and clean the affected areas. Make sure you wash those areas with hot water and let them dry. Apply clear epoxy resin to those areas (at least 5 coats) then smooth with epoxy filler. Apply a coatof epoxy on top and paint.

jameswilson29 · #6 (**permalink**) 12-08-2011

Could it be ice damage?

You might want to review Don Casey's material on fiberglass repair methods in the Boat/US library: BoatUS.com: Don Casey Library

He recommends polyester for above the waterline repairs, epoxy for below the waterline repairs. If the gouges are deep, you will need more than just polyester or epoxy resin.

I would also be concerned about whether and why your boat is floating below the DWL.

sailingfool · #7 (**permalink**) 12-08-2011

You should not lose the boottop stripe or your topsides appearance will go downhill.

Do you know why the boat is sitting 3-4" below the original waterline, can that be addressed?

If not, you should first raise the boottop, it looks to me like 3-4" or so. Then repair any damage, add a barrier coat, then bottom paint. If you dont do the barrier coat, you run the likelihood of more damage occurring.

RichH · #8 (**permalink**) 12-08-2011

Agree totally with Sailingfool.
What caused this is 'probably' there was too much 'hardner' added to the mix when the gel was first sprayed into the mold. This is quite common on boats from the 80s and can occur 'just above' the waterline due to the hull 'dipping' (rocking back and forth) into the water or from waves constantly wetting the bootstripe.

As SF recommends, simply raise the waterline by doing an epoxy + barrier coat, then decide how much 'higher' you want the 'bottom coat' to be. A good barrier coat in this area will be important to prevent further 'damage'.

If in fact the gel had too much hardener added when first sprayed be observant that this 'damage' doesnt develop 'higher' on the topsides .... the way to lessen or prevent is to not let the such gel become 'oxidized' and 'roughened' by occasional flat wet-sanding (1000-2000 grit !!!) and power buffing to a FLAT and VERY shiney surface. A good 'reference' for such 'buffing' would be http://www.sailnet.com/forums/gear-m...olish-wax.html.