OSMOSIS

j.hunter9999 · Dec 29, 2008

Dieter,
Your question about what to do about blisters might generate a
considerable amount of discussion. I've never dealt with blisters
myself. However, I know of many instances where others have made
decisions about blister repair. In virtually every case, the decision
to spend money on repairs centers around the age of the boat, the size
of the boat, the extent of the problem, and whether the boat will be
kept or sold.

In general, you were not misinformed that you can sail on your boat
for another 20 years with the blisters (osmosis). If the blistering
is fairly dispersed (far apart), there should be no discernable hull
strength degradation.

You could replace the hull (re-glass and gelcoat), but I doubt you
will realize any great structural benefit. The exception is if the
hull is saturated with osmosis, which may cause a weakening of the
GRP. (The juice inside blisters is essentially an acid that breaks
down the GRP). If it looks like bubble wrap, perhaps more extensive
repair is necessary. A better option, if you are convinced that the
osmosis needs repairing, might be to open each of the blisters (grind
open) and dry them out completely. Then, apply an epoxy to fill them.
You may notice additional blisters the next time you pull the boat,
but this is exactly what you should prefer (as opposed to blisters
redeveloping in the same locations).

If you are going to go with a total gel coat replacement, you should
probably wait until the blistering is at its worst. A 4000 euro gel
coat replacement, besides probably not being needed, is likely 75% or
more of the boats value. If you're not going to sell the boat, and
the blistering is not affecting the structural integrity of the boat,
do you really want to spend that amount of money?

If you're looking for light reading on the subject, check out Hugo du
Plessis. I think there was also an article in a boating magazine
several years ago that discussed the situation. I can't recall which
one...my memory is not what it used to be.

So, the options are basically to leave it be, treat them individually
or entire re-gel coat. Of the three, the gel coat is by far the most
costly. If you'd prefer not to spend the money, but still want to do
something, you may want to treat them individually this time. Then
take a look the next time she's out of the water. Worst case, you'll
spend some time and a little money to find out that you want to do the
entire bottom. If that's the case, you should have at least earned a
few percent (even in these times) on the 4000 euro that you saved, so
you can afford a beer while they are doing the work.

In any case, mine is only one opinion...no more right or wrong than
anyone else. Let me know what you decide. I would be curious to know
if they warranty the work against further blisters. If not, it may be
an indication that they are invevitable.

Jack

pjacobs55 · Dec 29, 2008

Hi Dieter,
This seems a very unusual occurence on a Vega!

I'm not too clear about how badly your hull is blistered.
You said "...They appear all over the hull in a distance of say
twenty inches."

Do you mean they cover the entire underwater portion of the hull, and
are about 20 inches apart? If this is the case, I agree with Jack's
message: don't ignore them, do "spot" repair, and see what you have
on the next haulout.

That's what I would do, anyway. Good luck with your repairs!

Peter
#1331 'Sin Tacha'

wxt8981 · Dec 29, 2008

Hi Dieter,
I have my Vega about 30 years; I haul out every 12 to 18 months for a new anti-fouling paint. (I clean the bottom about every 3 months (with the boat in the water)
On occasions I've seen small blisterts; I clean carefully and if necessdary, I used to fill any ground-out blister with fiberglass. So far, I think I've seen about 10 or 12 blisters. I applied the anti-fouling paint and usually don't see them at the next haul-out. In your case, I would use a good grinder, and if necessary, batch up with fiberglass. Then apply the anti-fouling paint and wait for the next haul-out to see what has happened.
I hope you don't need a complete cleaning (with a sand-blaster) .
Sound like you're German (my son's first name is also Dieter).
Also Prosit Neu Jahr and always a 'Handspanne' water under the keel.
Wilhelm, V-257

SVFlyAway · Dec 30, 2008

Dieter,

I once bought a boat that had thousands of tiny blisters (people thought I
was crazy, butI got a really good price). It was a J-boat so it differed
from the Vega in that it was cored. I had one of the machines you mentioned
peal off the gelcoat down to the first layer of laid up cloth. Then we let
it sit for about 6 weeks to dry out - this is very important. Since it was
in Seattle in the winter. the yard build a tent of plastic completely
enclosing the boat and we used propane heaters and fans for the drying.

Then I had the yard put on three layers of epoxy and fair it out. The first
layer differed from the second two as it was more structural than barrier
coat - I don't remember the exact type or brand. This was followed by the
Trinadad bottom paint.

As was said if you only have a few, just sail the boat and continually check
it. Also if you only have a few blisters you can just dig them out and fill
them. If you have the time and disposition to do it yourself, by all means
buy a good sander (with a shop vac attachment) get yourself a good
respirator, buy a box of 80 grit disks and proceed to remove all the
bottom-paint this will expose all the "pox marks" from the blistering which
you can fill. Then apply two layers of barrier epoxy and bottom paint. You
will never have a problem with this again.

Regardless of what fix you use, the important issue is to let the blister
area dry out for several weeks in the heat. Since your boat is in Greece
that shouldn't be a problem. If you just grind and fill the holes you may
very well seal moisture in - this you don't want.

Hope this helps,

Chris

From: AlbinVega@yahoogroups.com [mailto:AlbinVega@yahoogroups.com] On Behalf
Of WL
Sent: Monday, December 29, 2008 7:47 PM
To: AlbinVega@yahoogroups.com
Subject: Re: [AlbinVega] OSMOSIS

Hi Dieter,
I have my Vega about 30 years; I haul out every 12 to 18 months for a new
anti-fouling paint. (I clean the bottom about every 3 months (with the boat
in the water)
On occasions I've seen small blisterts; I clean carefully and if necessdary,
I used to fill any ground-out blister with fiberglass. So far, I think I've
seen about 10 or 12 blisters. I applied the anti-fouling paint and usually
don't see them at the next haul-out. In your case, I would use a good
grinder, and if necessary, batch up with fiberglass. Then apply the
anti-fouling paint and wait for the next haul-out to see what has happened.
I hope you don't need a complete cleaning (with a sand-blaster) .
Sound like you're German (my son's first name is also Dieter).
Also Prosit Neu Jahr and always a 'Handspanne' water under the keel.
Wilhelm, V-257

albinvega1493 · Jan 3, 2009

I am now wondering if osmosis blistering on Vega's has anything to do
with the production year of the boat? I do know that in the US,
fiberglass boats built after the energy crunch in the early 70's had
more tendency to blister because of a formulae change in the makeup of
the fiberglass resin. I am wondering if the same is true with the
Vega's? This would mean that newer Vega's would have more tendency to
get osmosis blistering than older ones. When I redid the bottom of my
Vega (hull 1493) a couple years ago, I stripped the bottom all the way
down to the gelcoat, and there were no blisters at all. Just curious.

Larry
hull 1493 "Kemanalea"
SF Bay area

sailshiva · Jan 5, 2009

Larry, I have wondered the same thing...our Vega, sail #1707, built in '73 has never had blisters. We've gone down to the gel coat, and gone over the hull with a fine tooth comb, but no problems at all.

bobnlesafloat · Jan 6, 2009

It was my understanding (advised - I'm no expert!) that because Vegas were built using Isophalactic resin and no colour fillers in their original lay-up (foresight or just a lucky choice?) they are not prone to suffering osmotic blisters? Never found one on Spring Fever - though we've had a few pinholes appear on the cabin roof's gelcoat, do they count?

Bob Carlisle
Spring Fever