Osmosis treatment - advice needed!!!!

[pat_detente]

Our ancient Moody (built in 1975-ish) is currently having osmosis treatment. The yard has taken off the top surface of the gelcoat and sandblasted it. We are just a bit concerned that they don't appear to have exposed all the glassfibre underneath. They have scraped off everything to one level, but there are a lot of areas where there is still a white coating - you can't see the glass fibres underneath these quite large areas. In some places they are more than a couple of square feet in size. We assume that in construction the gel coat went on in varying thicknesses.

Our concern is that the boat may not dry out sufficiently, underneath these areas, and we could end up with moisture being retained in the GRP.

Should we be concerned??? Sorry if my terminology isn't too good - this is our first ownership of a GRP boat, so very ignorant!!

Any advice is much appreciated!!!

 

[boatmike]

Yes you should be concerned. Make them do it properly!

 

[Csail]

Had out yacht done 5 years ago for about £4000 and it has come back! Not impressed.

 

[andy_wilson]

1. Have they excavated all the voids out?

2. Is the drying program being monitored by your surveyor prior to epoxy coating?

3. Is it a reputable and experienced yard?

4. Do you get a written guarrantee?

The treatment will be to remove a layer of affected gel-coat, and any specific and badly affected areas. Dry to acceptable levels (using force if required). Fill any voids and fair the surface. Apply epoxy protective layers to manufacturers specification and under the correct temperature and humidity conditions. (Prime/antifoul/launch etc.).

Your own surveyor is a possible additional insurance policy (provided he is covered if he says 'go ahead' and the coating proves to be ineffective).

 

[pat_detente]

Re: Osmosis treatment - advice needed!!!!

Thanks for the replies - it is a reputable yard, which is why we chose to take the boat there. They are monitoring the hull. We do get a written guarantee, but I will now be able to ask slightly better informed questions!!

Many thanks again!

Pat

 

[Birdseye]

Re: Osmosis treatment - advice needed!!!!

When my previous boat was done, there was another exactly the same alongside. This latter was done uinder surveyors supervision and he insisted that they simply left an open porous gel surface as you describe ie didnt dig into the laminate. I left mine up to the yard who took all the gel off, being both unwilling to pay for a surveyor and also wanting no arguments if there were problems about who was responsible - the surveyor or the yard.

Ironically, it was my boat that needed re-doing in the end.

I cant give you an answer directly - I dont know the state of your hull and I'm not an expert anyway. If you have any doubts, cough up some money on hiring someone like Tony Staton Bevan. Its better than ending up with an argument when it all goes wrong. Be careful about pressurising the yard simply to remove more - blasting isnt very controllable and you could end up with a thin hull with uneven patches.

Finally, no -one garauntees that an osmosis treatment is for ever. It isnt.

P.S. If you want to while away a week or two, search on "osmosis" on this site!

 

[pat_detente]

Re: Osmosis treatment - advice needed!!!!

Thanks for that info, Birdseye. i have emailed the yard manager with my concerns and am waiting his reply. It could be that he will give a similar explanation. they are a reputable yard and I am sure that they would not take short cuts, but our experience is in wooden boats so are unsure about what to expect.

Thanks again!!!

 

[moodymadness]

Pat,
I too am in the same position in the same yard again with patches of unpeeled gel coat.
Any update on your boat or conversations with the yard manager as a matter of interest.
Regards
Pete