Blisters
Valiants are infamous for their blister problems. Here’s my take.
Blisters form on the hulls of many different boats, for different reasons, and no one anywhere seems to have all the answers. I am just learning about boat blisters, so I have little qualification to talk about them. But I’m going to anyway. Sometimes blisters take the form of same-sized tiny little bubbles that are probably just spots where the paint is bubbling up. Other times they can become hand-sized. They can form on just the topsides (out of the water) and not the hull. Or vice versa. This is the important thing: most of the time blisters are merely cosmetic–they don’t affect the integrity of the hull whatsoever. They will not cause your boat to sink, bottom line. I am told that occasionally blisters can get so bad that they pass entirely through the hull, causing the entirely thickness of the hull to delaminate in a particular area. I have never seen a blister like this, I’ve never heard of a boat sinking from blisters, and honestly it’s hard for me to imagine how exactly that would happen. Even if the blister formed a weak area in the hull, it’s not like it ever gets weak enough to spontaneously form a hole and let the ocean into the boat. One thing is certain: blisters are very good business for surveyors and boatyards. I would guess that people spend more money on getting blisters ground out and reglassed and faired and repainted than any other single item of boat maintenance except bottom paint. In the case of the Valiant, the most popular theory is that the blisters were caused from the particular kind of fire-retardant resin that Uniflite used. Eventually they caught on and fixed it, but not before building a few hundred boats that seem cursed with an unfixable blister problem.
From experience, I can attest that the fiberglass in our boat oozes a black gooey pus. When I crawl way back in the lazarette where the fiberglass is bare and undisturbed, I can see some spots of black ooze, which I studiously try to avoid. The ooze is not very runny, but neither is it dried and solid. It’s the consistency of a really thick partially dried honey. And it’s really black. Nasty looking. Like someone spilled something on our boat five years ago and never cleaned it up. Captain Bob has said that it’s either really basic or really acidic, because he says it burns a little bit on the skin. Anyway, my guess is that this is the stuff that causes the blisters. If there’s a little pocket of it in the fiberglass near the hull, then it can pull water in through the gagillion waterproof layers of barrier coat and bottom paint (how it accomplishes that no one can explain) via osmotic pressure, forming a blister.
I have known Valiant owners that took their boat to the factory in Texas (after Uniflite closed up shop in Bellingham), had the entire hull ground down to bare fiberlass, glassed over it, epoxy barrier coated it, bottom painted it, and STILL had the blisters come back within 10 years. Now tell me how that’s possible.
In 2005 at Marina Real in San Carlos, MX, Syzygy (then Sunshine) had its hull ground down to bare glass, a heavy layer of fabric glassed on, 5 layers of epoxy barrier coat painted on top of that, and then a couple coats of an ablative antifouling bottom paint on top of that. The previous owners had a guy named Arturo do it, and said that his work was top notch. No blisters have reappeared (YET).
Matt & 2 Jons:
While there are many opinions as to the reason underlying the Valiant’s particular type of blisters, I think one explaination (albeit with several possible causes) really sums it up.
The Valiant blisters are NOT osmotic water blisters (ie, not due to seawater penetrating the gel coat via osmosis). They are accumulations of uncured or poorly-cured resin that migrate (also through osmosis) to the surface just under the gel coat where they form blisters. There are two main theories why the Valiants are prone to this. 1) the fire-retardant Uniflite used may have inhibited proper curing. 2) Valients were made during the oil crisis of the mid 70s, and good quality resins were hard to come by. Either theory has merit, and the most likely cause is probably some combination.
Good news is that two things happen as the boat ages. 1. the resin continues to cure, so less uncured resin exists to form new blisters, and 2. most of the uncured resin has already caused blisters, so less is available to cause more!
Another result of the Valiant type of blisters is they don’t need water to form. Thats why some of the early Valiants also have blisters above the waterline and on deck structures. But again, new blisters become much less likely as the boat ages.
I’m having blister problems with a 40′ Willard hull vintage 1973. Surveyors claim problem is caused by fire retardant resin used in the mfg. I have had the top layer of glass stripped and I’m in the process of grinding out thousands of blisters, nasty job; the surface looks like a lunar landscape. The plan is to build up the blisters with glass matt then fair the hull with a faring compound (structural product that contains glass fibers, red in color) I’m not yet sure of the name of this product. The entire below waterline area is to then be washed with baking soda to neutralize acids that may be present then to throughly dry out the hull. The entire area will then be covered with two layers of vynal-ester material then apply at least two coats of epoxy barrier coat followed by two coats of good bottom paint. Comments or suggestions will be very much appreciated, thanks.
Your plan sounds very thorough. Claims of why the blisters are happening are suspect–especially the fire retardant resin argument. But it doesn’t really matter where they came from, right?
We haven’t had to deal with the blisters ourselves, though our boat received the strip and reglass treatment before we bought it. With Valiants, the blisters return as often as not. What thickness of the vinyl-ester material will you end up with? Someone told us that if our blisters never returned, it would only be because of the thickness of the glass that covers over the bad layers (the idea being that new blisters still form, but they are confined below the new glass, which is thick enough to not “print through” and reveal the blisters).
If we get blisters, we won’t have the money or time to do anything about them, so we will live with them until it feels like they might sink the boat.
best of luck, I don’t envy the enormity of the project that you’re starting. I support the plan, sounds like you know exactly what to do.
[...] Blisters [...]
I too have a Valiant with blisters and have learned to live with them. My list of priorities re work is SSCC [ Seaworthyness, Safety,Comfort and Cosmetic] All i’ve read, including an article by a long time boat surveyor is that the Valiant blisters are not classic osmatic blisters and that there is no record of any boat having hull damage due to blistering. Thus I’ve put the blisters in the the Cosmetic priority which means I may get to it before I die.
I enjoy your blog and wish you well on your journey.