Ahoy all...
Has been a while... have been busy tinkering on Mojombo and am planning some big moves soon...(next year)...
Decided that I will plane the hull and repair the osmosis etc.
Has any one taken on such a big job before??? 42 feet of pain?
Also has anyone any knowledge of the availability of a second hand GRP plane, a moisture meter and fridge compressor for making a hull vacuum?
Any thoughts, tips or stories appreciated.
Seamus
I have never had to do an osmosis repair but I have seen a few. I would suggest having someone look at this for you to asses just how bad this is. Have not heard any good things about a hull peel. Just be careful what expert you have look at this. I would suggest checking back through sailing anarchy's fix it section for some honest answers.
forums.sailinganarchy.com/index.php?/forum/56-fix-it-anarchy/
Another good source is boatdesign.net.
www.boatdesign.net/forums/boat-building/
I was just talking to a pro who has done a huge number of repairs - careful spot cutting out, lots of rinsing, a thorough dry and fill was his advice. He wasn't a fan of the peel as you loose a lot of good with the bad.
Cheers
Bristle
I did a small ossie job on a 25 footer. I would suggest using a wire brush on a 4 inch grinder to gouge out the gelcoat. I got two vac pumps for free so look out for them. Vac bagging needs a bit of technique but is okay to do. Make sure you epoxy the whole thing before you antifoul.
Thanks for your thoughts guys. ill check out SA. Might Vlog it as a reference it i get around to it.
Seamus
I sanded the blistered gelcoat off my 10m boat. I left behind some very thin gelcoat in a blotchy (patches) pattern all over the bottom of a hull as a reference to the depth of my sanding. I didn't use a gell plain because the gelcoat was very uneven in thickness and the blistering was only in the gelcoat.
The boat then dried out for 2 years
I faired the hull with west systems 410 and coated the bottom with a dozen coats of Wests epoxy
I had thought of sand blasting the hull but I chose to avoid that solution because the hull wasn't that thick in places.
I havnt done it, but I have worked on boats that have been peeled. Something to consider is that it is much harder to repair blisters if/when they start occurring again. This is because the barrier will be much thinner and it's difficult remove old anti foul without going through to the glass. So it is hard to get a wide enough taper on the blister hole to avoid pasting epoxy on top off old antifoul. It will also be easier to puncture through the new barrier.
I wouldn't do it if the blisters were deep, but probably accept it if I had lots of shallow blisters.
Also those soft green and light brown micro balloon fillers seems to fail more than the white international epi-fill type harder fillers.
a
I'm currently sanding off everything below the waterline to the fibreglass on a 55 year old 33 footer. I don't have osmosis as such, but there a small amount of dark red fluid oozing out from tiny fissures which I'm told is styrene. I had to take off about 5 layers of antifoul with paint stripper and sand off layers of undercoat, epoxy fairing, and clear epoxy.
In retrospect I should have just slapped another another couple of coats of antifoul and put her straight back in the water after I bought it 6 months ago. I console myself by thinking how it will sail better with a smother bottom and slightly less weight. It has been good to see what's underneath though. It has had a lot of repairs over the years, but it is in quite good condition.
Hopefully I'll be in the water in 2 months. I've almost finished sanding the bottom. Have to remove redundant seacocks and transducers, reinforce a few thin spots and the rudder, and paint the topsides, which have already been sanded. Coating the bottom with clear epoxy, hi-build epoxy then undercoat. Was planning on putting CopperCoat expoxy antifoul, but as I'm running out of money will now use abalative antifoul instead.
When I'm on the water, I'll sand and vanish the timberwork, fix a couple of soft spots in the Airex cored deck and paint the cabin.
Select to expand quotekimtrang said..
I'm currently sanding off everything below the waterline to the fibreglass on a 55 year old 33 footer. I don't have osmosis as such, but there a small amount of dark red fluid oozing out from tiny fissures which I'm told is styrene. I had to take off about 5 layers of antifoul with paint stripper and sand off layers of undercoat, epoxy fairing, and clear epoxy.
In retrospect I should have just slapped another another couple of coats of antifoul and put her straight back in the water after I bought it 6 months ago. I console myself by thinking how it will sail better with a smother bottom and slightly less weight. It has been good to see what's underneath though. It has had a lot of repairs over the years, but it is in quite good condition.
Hopefully I'll be in the water in 2 months. I've almost finished sanding the bottom. Have to remove redundant seacocks and transducers, reinforce a few thin spots and the rudder, and paint the topsides, which have already been sanded. Coating the bottom with clear epoxy, hi-build epoxy then undercoat. Was planning on putting CopperCoat expoxy antifoul, but as I'm running out of money will now use abalative antifoul instead.
When I'm on the water, I'll sand and vanish the timberwork, fix a couple of soft spots in the Airex cored deck and paint the cabin.
Nice looking boats. At that age the fibreglass boats have very heavy scantlings. I would be more inclined to treat the underwater surfaces the same as a timber vessel or fibreglass boat and follow a paint companies recommendations for paint. I presume you mean back to the gelcoat and not fibreglass. 2 or 3 coats of grey primer followed by the ablative antifoul.
Where a bouts in the country are you?
Select to expand quoteRamona said..kimtrang said..
I'm currently sanding off everything below the waterline to the fibreglass on a 55 year old 33 footer. I don't have osmosis as such, but there a small amount of dark red fluid oozing out from tiny fissures which I'm told is styrene. I had to take off about 5 layers of antifoul with paint stripper and sand off layers of undercoat, epoxy fairing, and clear epoxy.
In retrospect I should have just slapped another another couple of coats of antifoul and put her straight back in the water after I bought it 6 months ago. I console myself by thinking how it will sail better with a smother bottom and slightly less weight. It has been good to see what's underneath though. It has had a lot of repairs over the years, but it is in quite good condition.
Hopefully I'll be in the water in 2 months. I've almost finished sanding the bottom. Have to remove redundant seacocks and transducers, reinforce a few thin spots and the rudder, and paint the topsides, which have already been sanded. Coating the bottom with clear epoxy, hi-build epoxy then undercoat. Was planning on putting CopperCoat expoxy antifoul, but as I'm running out of money will now use abalative antifoul instead.
When I'm on the water, I'll sand and vanish the timberwork, fix a couple of soft spots in the Airex cored deck and paint the cabin.
Nice looking boats. At that age the fibreglass boats have very heavy scantlings. I would be more inclined to treat the underwater surfaces the same as a timber vessel or fibreglass boat and follow a paint companies recommendations for paint. I presume you mean back to the gelcoat and not fibreglass. 2 or 3 coats of grey primer followed by the ablative antifoul.
Where a bouts in the country are you?
Pardon me for being vague. It's a LeComte Medalist built in 62. It was sailed over from the US a by a ex Au navy guy. I'm on the hard in Port Stephens. I paid $13,500 for it. It was mentioned in this thread;
www.seabreeze.com.au/forums/Sailing/General/Bargain-2
Yes, it has timber embedded horizontally in the hull. It has a few issues, but nothing too major. The Barient 28 ST winches needed to be replaced as they were suffering severe corrosion on the aluminium base. The chainplates are plain steel and are suffering corrosion. One has been done and I think I can get away with the others for a while. I've been thinking of replacing them with external bronze ones. It won't be great for the aesthetics but I refuse to dig out and replace them internally. There are a couple of small soft spots in the deck, but I think that is in the paint layers. The Airex core in the cockpit had few square inches of water intrusion, but i'e dried that out and will grind and refill it. There is some internal wood rot from leaks, including a bulkhead, but nothing to worry about
There is no gelcoat below the waterline. I'm sanding to the chopped strand layer. The gelcoat on the decks where the paint has flaked away is just mass of cracks.
There are some very good videos on YouTube showing osmosis repairs in detail. Also on repairs and painting etc.
www.marinesurveyor.com/meters.html
I had a read of this a couple of days ago after reading plastic boars are very hard to read accurately for the beginner.
Wood is much easier nand the meters are cheap in comparison. Any thoughts on this please?
I personally think all the talk/hype/hate around osmosis is overrated. No boat has every sunk form it. Sure it looks bad but you only ever see it when its on the hard. Gouge it out with a chisel, grind it back, fill with epoxy, couple of cats of primer and antifoam over it. and re-do some spots easy haul out.
My last boat had been sand blasted and left to dry for 2 years and repainted by professionals, 7 years later it was back to the same as before.
An alternative to a moister meter after you have grind out the osmosis is to sticky tape clear plastic sheeting across the exposed area and leave it for a few days. If there is still moisture in the glass the plastic will be wet on the inside. It took about 3 months for my boat to dry out (in winter). Every week I pressure cleaned the hull to remove any impurities, which slows the drying process.
Ilenart
how far apart are the blisters ? if they are 400- 500mm apart I would treat as individuals. If they are at 100mm centres , I would consider plaining .
Select to expand quoteSandS said..
how far apart are the blisters ? if they are 400- 500mm apart I would treat as individuals. If they are at 100mm centres , I would consider plaining planeing.
There!! Fixed it for you. 
Osmosis!! Grind it out, dry it out, epoxy fill it out and get back to sailing.
I have a mate who did his 39 ft centre cockpit on the slip at gravelly beach if you would like to pick his brain for knowledge on how best to attack it i am sure he would give you a great deal of insight
he is a perfectionist
Osmosis repair, hate even the thought of it.
Few years back, we started on a mates 42 footer, laid in 1974, "just a few spots"...
Well, it turned out to be a two and a half month nightmare on the hard.
First it was the removal of the years and years worth of hard antifoul first only in spots to get to the larger blisters. Then the revelation, that the whole hull must be cleaned up, hence the blisters were so many and so deep.
Cut the long story short, the rep from international visited three times and we eventualy finished the job, but...it was a proper pain in the butt and we never got it right because the hull was riddled with osmosis deep deep in the material. It was very sloppily laid in 74.
It was up for sale again, a while ago.
This is my personal opinion, don't touch a boat riddled by osmosis, with a sixty foot barge pole, less you are a masochist.
