Hi,

Very new here - so go easy on me; but help appreciated if possible.

I have a reasonably decent size GRP sailing yacht, which is quite old, and the gel coat is suffering a lot in discolouration. Most problematically there is a lot of fine crazing. This isnt structural stress related, but is rather fairly uniform across the decks and coachroof seemingly from uv deg or possibly the gel coat being laid up a bit thick back in the 80s. Any painting over the gel coat as is would likely just show through the crazing in time. The extent of crazing makes it impossible to feasibly open all the cracks and fill; while the boat value doesn’t make gel coat stripping viable at all.

I have had a few people recommend the gel coat can be skim coated with an epoxy resin (after a thorough clean and keying in parts) to form a new smooth base (possibly after some sanding) on to which a paint coat can be applied.

This seems like the way forward and a cost and effort I’m willing to take on, but I’m trying to decide on the best epoxy for the job. The variables I have to work to are:

* will need to skim coat both flat, vertical and angled surfaces, which I guess mean high viscosity?
* will be applying in the open air, or at best under a tent; so dust control will be challenging; but I also quite an area to cover;
* would like to try and do over the winter, while boat is out of water, but this mean I need something tolerant to lower temps or that can mixed to compensate for lower temps; or possibly wait for warmer days;
* needs to be paintable, if necessary after sanding;
* would like a strong hard surface, but likewise GRP does tend to flex somewhat, so a degree of flexibility might be necessary

I realise that some of these and at odds so compromise needed. However, I’m not chasing a 100% perfection.

any help appreciated?


John

Thanks for replying. It isn’t osmosis. This work I want to do is on the deck and coach roof of the boat, not the hull. I mean the boat doesn’t have osmosis; which has been treated in the past with an epoxy coating, but that is an different story.

I’m very much talking here about a cosmetic issue on the decks.

See attached photo. This actually shows a particularly bad area where there is a combination of superficial scratches (which don’t go down or the structural fibreglass) and the crazy, which is so dense that it gives that dark colouring when seen from a distance. This looks as though it is lots of small cracks all the way through the gel coat.

I’m not interested in doing a proper repair job here; the value of the boat will never merit it. I just want to improve the cosmetics and get a few more years out of here.

No amount of sanding will remove all of these, so painting over will always end up showing through. Hence I want to apply an epoxy coating first, to form a new layer that will get in to the cracks, fill them and create a new flat finish, that I can sand down smooth before painting.

Just trying to work out which is the best type for this application.

Thanks


John