Older glass boats

[psneeld]

Originally Posted by Pete7

Ouch, that looks nasty, but surely that is layers of GRP that haven't bonded properly when initially laid up?

Pete

Nope...classic hydrolysis....

Blisters are only part of the issue. Blisters MAY or MAY NOT occur...hydrolysis IS ALWAYS happening to some degree.

Don't believe me??? Read through white papers from the composite tank and piping industry...they have a clue...the boating industry is WAYYYY behind.

[David_Old_Jersey]

Originally Posted by benajah

I am restoring a Westerly Cirrus 22 from 1968 I bought for 600 bucks right now.....

Any of the very early Westerlys (pre Centaur) have a layup that could probably stop a bullet . Afterwards they learnt "better" and things changed radically. Not to say that everything in 60's was Osmosis proof - nor was built well! But IMO no core is one of the keys to longevity, even if that also has downsides.

But certainly the mindset of many (but not all!) boat builders back then was to build a boat that was capable of lasting a lifetime. or 2. Of course most (all?!) of those boat builders have long since gone broke .

But really it is a case of each model (and even years of production) being different, as well as how each boat has been looked after (and where). Some far less likely - but IMO none 100% immune.

[barnakiel]

Originally Posted by Pete7

Ouch, that looks nasty, but surely that is layers of GRP that haven't bonded properly when initially laid up?

Pete

Or perhaps a layer or two added to an already cured hull?

b.

[psneeld]

Originally Posted by barnakiel

Or perhaps a layer or two added to an already cured hull?

b.

nope...not an idiot here...been repairing glass boats a long time...last 11 years in the marine industry as a pro.

the 1/2 inch hull in places is now down to 1/4 inch where some of that roving came off...I can oil can the areas with my bare hand where it was removed.

[barnakiel]

Amazing things.

Very interesting to see all those examples ON OTHER PEOPLE'S boats ...

barnie

[David_Old_Jersey]

Originally Posted by psneeld

nope...not an idiot here...been repairing glass boats a long time...last 11 years in the marine industry as a pro.

Can't quibble with your experiance - but surely something else going on with those layers of Fibreglass (in addition to any "Osmosis"). The only time I have ever seen something come off "dry" like that is either from piss poor layup / bulkheads that have delaminated off.

I will concede however that my hands on experiances are fairly limited.

[psneeld]

Originally Posted by David_Old_Jersey

Can't quibble with your experiance - but surely something else going on with those layers of Fibreglass (in addition to any "Osmosis"). The only time I have ever seen something come off "dry" like that is either from piss poor layup / bulkheads that have delaminated off.

I will concede however that my hands on experiances are fairly limited.

Nope...that's EXACTLY what hydrolysis does to the resin...disolves it leaving dry layup behind. That's why when people start off with blisters in a discussion...they are not very informed with what's really going on with the hull.

Here's what Mineret said last time I posted these pics..."Classic result of hydrolysis. This is why saturation is a bad thing."

http://www.cruisersforum.com/forums/...s-62167-8.html

[Geoduck]

POLYESTERMITES!!! RUN FOR YOUR LIVES!!! AAARRRGGGGGG!!!!!!

[CharlieCobra]

We just are finishing up a peel job on an SC-50. Hydrolysis will indeed cause a hull to delaminate. Polyester is not waterproof. Epoxy is. Trouble is, ya have to get past the bad laminates for it to work.

[dirkdig]

So it is essential to have a complete barrier of epoxy on the bottom under the antifoul to fully protect the fibreglass?
I have a few patches where the epoxy has cracked off,should i do a epoxy barrier patch up?

[psneeld]

Originally Posted by CharlieCobra

We just are finishing up a peel job on an SC-50. Hydrolysis will indeed cause a hull to delaminate. Polyester is not waterproof. Epoxy is. Trouble is, ya have to get past the bad laminates for it to work.

Nope...just less so...keep researching.

[psneeld]

Originally Posted by dirkdig

So it is essential to have a complete barrier of epoxy on the bottom under the antifoul to fully protect the fibreglass?
I have a few patches where the epoxy has cracked off,should i do a epoxy barrier patch up?

If the epoxy cracked off...it sounds like it may have been applied poorly/incorrectly...you need to find out what is going on under the rest of it.

My bottom looked fine till I started cleaning up a few blisters...the deeper I went...the more I found.

[CharlieCobra]

Originally Posted by psneeld

Nope...just less so...keep researching.

Do you have a link for this? I've been told by everybody that epoxy is the only waterproof solution currently out there. If it's not, I really need that information.

[Pete7]

Originally Posted by CharlieCobra

Do you have a link for this? I've been told by everybody that epoxy is the only waterproof solution currently out there. If it's not, I really need that information.

Charlie, its the high degree of waterproofing that you are after with epoxy although it isn't waterproof for ever. Sure eventually the water will get through but it might take 10 or more years. Our 1989 hull was epoxy treated in 2000 (thankfully). When we bought it in 2007 the moisture readings were the same as the topsides after being lifted out for an hour.

Sure the epoxy will eventually break down and I will have it slurry blasted off and re-apply, but I am hoping for 15 years before I need to do that.

Pete

[Cheechako]

Blisters just seem to occur on certain boats.... and I dont think anyone has the answer yet. Some boats seem to develop none. Some boats may get an occassional few. No problem.
The boat you want to avoid is the one that gets a lot of them. Some of these boats have been repaired 2-3 times (albeit not properly). Try walking through the boat yard and look at boats that have been completely sanded (not peeled) you often see two colors or more of filler that was used to fill the blisters years apart.
If I had to guess I would say '71-'85-ish were the worst years.... but that would simply be a wild guess. Maybe it's just because there were a lot of boats built in those years and they were getting older! I had a 74 that was terribly infested and an 85 also! I had another 85 that never had one. Both 85's were Taiwan built.
A thick rolled on epoxy resin layer (after months of drying on a bad case) seems to do the job on boats I've had and seen...