Posted by Mel Layton on April 04, 2000 at 06:39:35:
In Reply to: Re: Acid bubbles above waterline. posted by Blomberg Bengt on April 01, 2000 at 14:46:07:
Hi Ron,
I recently bought a 30 year old Westerly Windrush which also has osmosis bubbles above the waterline. When burst, with a screwdriver, there leaked out an acidic liquid. A sure sign of osmosis. I have ground down the gelcoat with an angle grinder with sander attachment and found this successful at getting down to the laminate where the problem resides.
The area effected is on the topsides around the cockpit area. This I believe is due to the fact that there is a large unventilated space under the cockpit( where an engine would usually be located)and bilge water has been collecting there for years. This water condenses on the hull and seeps OUTWARD through the fibreglass. I have no idea what exact materials are used to make up the GRP hull.
People usually express doubt when I tell them that the bubbles are above the waterline.