Might have the pox?

[CalicoJack]

Our Tyler moulded yacht was built in 1977/8. Over the last eight years she has been in the water most of the time, coming out for 2/3 weeks for annual maintainence. She came out last Thursday and I found a number of small blisters, perhaps 8 in number, about 5mm in diameter on the keel. The original plan had been to soda blast the old antifouling off, epoxy the hull and then cooper coat it. Today I managed to catch up with a surveyor who was in the yard on another job. He had a quick look and having put his meter on the hull said that the reading were high and it could well be the pox. He suggested soda blasting and epoxy filling any of the blisters that burst in the process, then priming the hull and antifouling it. Carry on using it, but don't coopercoat was his advice. Any thoughts?

 

[TQA]

Grind out, wash out, fill with epoxy, prime and antifoul.

Repeat as required on future haulouts.

Eight blisters? Don't sweat the small stuff.

 

[superheat6k]

If the moisture content is high then epoxying the whole hull will trap the moisture in and the osmosis could get worse, however a few small blisters dealt with as suggested then worry about something else - it's a boat, it sits in water, it gets wet.

This might be of interest ...
https://www.dropbox.com/s/65lt77q4mnk0z3l/Osmosis - a short guide.pdf

 

[oldsaltoz]

Nothing to get to excited about, as stated above use a grinder (40 grit) and remove the blister, checking for a y fluid as you grind, then look for a slightly darker line, brownish yellow about 5 to 10 mm wide and follow this grinding it out as you go, it should lead you to the wet spot in the lay up, remove all discoloured material and any small voids or what looks like not enough resin in the glass.

Give the area a wash and put a heat gun on it for a few minutes, just don't heat it up more than than you stand when you put a finger on it.

Repeat the wash and heating till a moisture reading (Taken after cooling, + and hour or two). then wash with Acetone and lay up with Epoxy resin and cloth. NOT Chopped Strand Mat. Then finish with copper coat (epoxy mixed with Copper filings)

Job done.

Good luck and fair winds.