How do I know if they're blisters?

[cyrano138]

This is my first boat bigger than a sunfish or a hobie cat, but at least for those I loved sailing in 25 kts. I will have to learn to reef and put up a storm sail.

I'm on the gulf coast of Florida and I want to have it in the water by spring so I can spend the summer and next winter stress testing it before a bigger trip next summer.

[rossdv8]

I was told when I was young "Reef Once - Reef Early - Sail Upright".


If you sail solo or with inexperienced or timid crew, I found it was useful. You probably know form Hobie sailing, if you can sail with smaller sail area (when you are not racing) you can still fly a hull in a breeze if you want to, but you break less stuff and you can admire the scenery.


A monohull between 20 and 30 foots often feels nicer sailing more or less upright.
Here's my little Cavalier 26 in about 15 knots of breeze with two crew who had never been on a yacht before let alone steered one.

https://www.youtube.com/watch?v=UWoDgIUmqPE

Seas were only up to a metre (it looks a lot less, but we had 'wind with tide' which makes a huge difference. We're towing a 12 foot aluminium dinghy with its 4-stroke outboard on the transom and only heading about 30 miles across a passage.


To help the crew feel comfortable I
1) Furled the main and sailed under only the biggest Genoa (gives me about 7 knots boat speed)
2) Got the crew to alternate on the steery thingy. (Takes their mind off being tossed about).


We were still far from upright, but could still make a cuppa and cook lunch at the galley.


This by the way, is the second of the two yachts referred to in my earlier post - lost when cyclone Debbie ripped through The Whitsundays, and Shute Harbour, where I had my moorings. She was getting close to 40 years old!

If you can sort out your weather early and set sails for what is forecast, rather than the fastest initial boat speed you can get - you can make life a lot more 'worth living' - and save money on gear.

[cyrano138]

Definitely good advice. Nice vid!

[rossdv8]

Thanks. I was looking for the pics of the blisters on that boat when I bought her, but I can't find which drive they are stored on.

I only recently sold my 'spare' 24 footer that I was planning to ship to the Philippines to join a 20 foot Banca that I bought for taking visitors around the island. But health problems resulting from a blood infection picked up in the mangrove mud when I was trying to salvage stuff from the wreck of the yacht in the video in 2017, meant that I can't return to the lovely island where we built a home.


Ah well, as one of our Aussie 'heroes' supposedly said as they were about to hang him - "Such is life..."

[teneicm]

Didn't see this mentioned, but I did just skim some of the replies, so apologies if this is a repeat:


After you get everything opened up and sanded, spend at least a week washing the hull 2x a day with water as hot as you can get it (spray to get the hull wet, a quick brushing to the affected areas, rinse with more water, done). The object is to leach the acid residue from the blisters out of the surrounding laminate. Leaving it behind can effect the adhesion of the repair and potentially help to kick-start new blisters.

[cyrano138]

Originally Posted by rossdv8

Thanks. I was looking for the pics of the blisters on that boat when I bought her, but I can't find which drive they are stored on.

I only recently sold my 'spare' 24 footer that I was planning to ship to the Philippines to join a 20 foot Banca that I bought for taking visitors around the island. But health problems resulting from a blood infection picked up in the mangrove mud when I was trying to salvage stuff from the wreck of the yacht in the video in 2017, meant that I can't return to the lovely island where we built a home.


Ah well, as one of our Aussie 'heroes' supposedly said as they were about to hang him - "Such is life..."

Sorry to hear it, but hey there's more adventures of other kinds maybe?

[cyrano138]

Originally Posted by teneicm

Didn't see this mentioned, but I did just skim some of the replies, so apologies if this is a repeat:


After you get everything opened up and sanded, spend at least a week washing the hull 2x a day with water as hot as you can get it (spray to get the hull wet, a quick brushing to the affected areas, rinse with more water, done). The object is to leach the acid residue from the blisters out of the surrounding laminate. Leaving it behind can effect the adhesion of the repair and potentially help to kick-start new blisters.

It's not a repeat, though some have suggested alcohol and acetone. I'm not sure I'll have access to hot water at that yard. Would it help to use a basic solution like a slurry of baking soda (someone else's suggestion for determining if there are blisters)? For whatever it's worth, I haven't opened one yet that had any liquid in it, but then there boat's been out of the water for a few years at least.

[teneicm]

Originally Posted by cyrano138

It's not a repeat, though since suggested alcohol and acetone. I'm not sure I'll have access to hot water at that yard. Would it help to use a basic solution like a slurry of baking soda (someone else's suggestion for determining if there are blisters)? For whatever it's worth, I haven't opened one yet that had any liquid in it, but then there boat's been out of the water for a few years at least.

The blister contaminants in the layup will dissolve readily in water, not certain about alcohol and acetone (would guess alcohol yes, acetone maybe). But those are expensive and water is cheap and effective. It doesn't matter if it's not hot, hot water will just help it. The key is repeated cycles of washing as the water slightly permeates the fiberglass, dissolves the contaminants, and as it dries it leaves behind a film of the contaminants behind on the surface that get washed away the next time. I'd imagine the blisters will all be dry if the boat's been out of the water for 3 years. But if you don't get rid of the stuff, it will just absorb any water it can find and re-swell into a blister.


Some of the stuff recommended here will be overkill for you, but this is a good start to understanding the issue and best practices for remedying it:
https://www.westsystem.com/wp-conten...Prevention.pdf

[cyrano138]

Sounds like the "poorly saturated resin" I was seeing is more likely hydrolysis.

In these two pictures the outer layer looks pretty much exactly how hydrolysis is described in everything I could find. In the picture where I ground away a blister the resin underneath looks dark and no fibers are white or visible.

That's a bummer. I really don't have the resources to do a peel and re-laminate.
If I understand it correctly, the outer layer of mat isn't generally considered structural, but unless I remove it, the water that causes the drivers to appear visible will leach further into the structural layers over time.

So, is the boat just a lost cause unless I somehow figure out how to turn the hull over, peel the outer mat and lay up laminate over it?

[teneicm]

Yeah, it looks like there is a bit of hydrolysis going on, but not surprising if that was the area that had lots of those blisters in the gel coat. It's looks like its only in the chopped strand mat, so it's doubtful that there are any structural issue. The gold standard would be to peel the hull and re-laminate. But that's not needed (or cost justified) in many cases. I'd probably just open up the blisters, wash out the dried hydrolysis compounds, fix the deep blisters, and then barrier coat. Once back in the water (especially if it's in warm water), don't be surprised if the same small blisters keep popping up.



Do your research and take everything I've said with a grain of salt. I'm just some schmuck on the internet who's had to deal with his own blister issues.

[rossdv8]

The link here is interesting, I'm 'Old' and wobbly and still call the blisters osmosis - like we did in the 'olden days' D: But as mentioned above, it is technically hydrolysis. Still water migrating through absorbent material (laminates).

So one interesting thing I saw in the link was "Studies of hundreds of larger hulls with heavy woven roving mats in the laminate have been undertaken. All were found to have numerous sites inside each roving layer and direct evidence of de-laminations deep in the bulk caused by degrees of severe hydrolysis. Significantly most hulls showed no telltale blisters at all!"
(BEAR in MIND that the following was written by someone selling a system for repairing this problem...



What is Osmosis? Osmosis Blisters, Osmosis treatment


The above suggests a lot of yachts might be sailing with osmosis / hydrolysis happening inside the layup, but with no external damage. AND that no matter what used boat you buy, you might get one with that happening!

All licenced yacht surveyors should have a moisture meter. You can get these blokes by the hour, to go over your boat completely (Insurance or Pre-Purchase survey) ot if you already own the yacht, you can get him to just do a 'hull moisture and soundness check'.


The last involves going over the hull from just above the waterline, then all over the bottom, with a moisture meter and wandering around the hull hitting it with a bangy thingy and listening for hollow sounds.
It was not overly expensive for me to have a soundness / moisture check done - and it was worth every dollar. I decided I could live with what he found, and went ahead and bought the old girls.

[teneicm]

Originally Posted by rossdv8

BEAR in MIND that the following was written by someone selling a system for repairing this problem...

That’s the key to keep in mind reading that article. Lots of good info, but I think the fears of actual structural damage are a bit overblown, at least based on all the other papers on the subject I’ve read.

[cyrano138]

I guess I was hoping I'd get away with sanding, opening and filling blisters, and barrier coating it for a 20 year boat.

Now I have to decide how much to sand, whether to remove the entire gelcoat and then grind away the badly hydrolyzed mat (unless it's just everywhere in which case the best I can hope for is that it will last a few years before the water moves deeper into the laminate and the boat needs to either be thrown out or given thousands in repairs for a peel and layup), and whether I'm doing more damage than good by barrier coating it.

[Don C L]

I can only say from the experience I had with a friend whose boat had a good deal of osmosis, oozing brown vinegarish liquid, and some were deep in the mat. The baking soda idea came to us so we could neutralize the acid, reducing the catalyzing effect, and then flush it and dry it, to be sure it would dry well. It seemed to work. We filled all the divots and put on the barrier coats. My own take on it was that chances are there will be more blisters to come but I doubt patching them increases their chances or makes them worse. And I doubt, at least in his case, the boat will suffer structurally measurably in our lifetimes since the hull is so thick.

[cyrano138]

The cal 20 hull is pretty thin. I guess I just need to sulk about it for a bit, and then accept that I'll have to start saving for another boat before too long. Maybe it'll last awhile.

I haven't been able to do any work on it for a few weeks because of finals, but I'll be getting back to it next week and then I'll have a better idea of just how extensive the hydrolysis is. If it's isolated in a few places I can grind away and lay up some fiberglass without having to alter my repair plans too much. If it's everywhere I don't see an efficient way to grind the whole hull down without having to invest in a power planer or something that would strip it. And I'm not really sure it would be worth the time and expense for what, in perfect restored condition, would be a $3,000 boat.