Bottom Job

[TritonSailor]

I'm currently working the bottom of the boat, well I'm working alot of things, but the bottom is a priority. I sanded the whole bottom bare to gelcoat, it had 15 years of old hard paint that chipping away. There is a lot of cracking and pits in the gelcoat which I have begun filling with West System resin and low density. After I did the whole bottom, I was thinking of putting on about 4 gallons of Interprotect 2000E, alternating colors between gray and white. I have been told by some people at the marina that it isn't necessary and a waste of time, just whip some bottom paint on it and go. I wanted to get some info here since I'm surrounded by people who have far more experience than I. Any Advise would be appreciated.






Thanks

Jeff

[Cherp]

I think your original plan is a good one.

[SkiprJohn]

Is the red color the West Systems with low density filler? Does it fill the cracks and pits pretty well?
I am a big proponent of not doing any more than you have to. Once all those cracks and pits are filled with your epoxy mix, sand smooth and do one clear coat of epoxy and then put the bottom paint on. You should be hauling out once every 3 years or so. In that case you can check it again and fill anything that might appear. I think you'll find that there will be no more cracking and pits.
Regards

[TritonSailor]

Hi SkiprJohn,

Yes, that's what it looks like when it's all mixed together. It works like a charm, fills in everything making it a nice smooth surface to paint.

Jeff

[s/v 'Faith']

I agree with John,

Especially so since your Triton is not prone to blisters or other problems. Fill the cracks (make sure to do a through fresh water scrub after to get the blush off) and paint the bottom paint on.

[cburger]

Judging by your pictures old, porous, gel coat. If you love the boat take the time to do the job right and barrier coat the hull. No need to alternate color with the Inter Protect, if you plan to use an ablative bottom paint you can alternate colors, when the bottom indicator color shows through it's time to start thinking about a re-coat.

[s/v Jedi]

Some cracks are one thing, but the photo's clearly show pieces of gelcoat falling off. That process will continue and I see two choices:

1. Like what you do, clean up as best as possible and fair it out, filling up the cracks and pits. You must realize though that the maximum effect of that is that you keep those pieces in place by stabilizing their edges only, i.e. their adhesion with the hull isn't restored. But, when you follow it up with a barrier coat, you encapsulate them and as long as the barrier coat stays intact, they will stay put.

2. Grind all the gelcoat off and give it a real barrier coat. The grinding is the problem here. Alternative is a gelcoat peeler robot which means you throw money at the problem to solve it but it is effective. After the gelcoat is gone, the barrier coat and fairing is the easy part.

In your shoes, I would take option 1 and start saving for option 2 in case the problem returns in the future. The more barrier coat you put on now (and the better it is), the longer it will be stabilized because it will hold the gelcoat pieces together. I would consider West System for it (they have a small booklet about it). At some point the barrier coat will loose but who knows how far into the future that is ;-)

cheers,
Nick.

[forsailbyowner]

I had to make the same decision. I was told barrier coat wouldn't do much good unless I dried out the hull. I didn't at the time but have plans to in next couple years. Will require months on the hard and purchase of gelplane to remove surface gelcoat and blister repairs. My plans are to rent space at yard and do canvas work to stock up funds while boat dries out. Then do an actual epoxy layup with a couple layers stitchmat. Followed by barrier, trinidad hard in red, then many coats of blue Jotun ablative.

[s/v Jedi]

I think you can rent a gel plane but I would look around for a yard that has access to a peeler.

If the laminate under the gelcoat is in good condition, you don't need to add fiberglass. It gets expensive to do that because it takes a lot of epoxy, plus you add weight that the designer didn't think is needed.
Even really bad looking gelcoat has good laminate underneath most of the time. I would only add fiberglass when I would find a lot of damage from osmosis blisters into the laminate. If it looks good, I would do just a barrier coat to replace the gelcoat.

Indeed, a contrasting colored hard Trinidad coat under the ablative paint makes sense. Many cruisers use a different color of the same ablative paint instead. Sales people make that happen by warning about incompatibility between the paints. But I really think you can put anything over hard Trinidad and can easily test that before buying (everybody is using it in the yards).

cheers,
Nick.

[Christian Van H]

Man, you got some good advice here. Nick on Jedi is SPOT ON! You cant get better than this!

[TritonSailor]

Originally Posted by s/v Jedi

I think you can rent a gel plane but I would look around for a yard that has access to a peeler.

If the laminate under the gelcoat is in good condition, you don't need to add fiberglass. It gets expensive to do that because it takes a lot of epoxy, plus you add weight that the designer didn't think is needed.
Even really bad looking gelcoat has good laminate underneath most of the time. I would only add fiberglass when I would find a lot of damage from osmosis blisters into the laminate. If it looks good, I would do just a barrier coat to replace the gelcoat.

Indeed, a contrasting colored hard Trinidad coat under the ablative paint makes sense. Many cruisers use a different color of the same ablative paint instead. Sales people make that happen by warning about incompatibility between the paints. But I really think you can put anything over hard Trinidad and can easily test that before buying (everybody is using it in the yards).

cheers,
Nick.

So Nick,

Your saying screw the fiberglass resin, just put on a few coats of Interprotect 2000E, then paint on the Interlux Micron Extra and call it a day?

[Bloodhound]

Two words: barrier coat! I worked on a Soling a few years ago, ground out blisters, filled and faired, but did not barrier coat - just bottom paint. Never again. My son now has the boat. We've dried her out in a metal building for a year and are ready to start work. This time there will be multiple coats of barrier protection, then bottom paint, then anti-foul. No guarantee against future blisters, but we'll have done all we can if/when they happen.

[s/v Jedi]

What I say is, for making the boat better than new and after removing the flaking gelcoat (all the gelcoat, not just bad spots), no fiberglass is needed when the laminate is still good. Gelcoat is not structural, it's a finishing method, much like paint. When you re-paint the outside of a wall of a house, you're not going to put an extra layer of bricks all around the house... at least, I wouldn't.

But I didn't say no resin. I would tend to use West System epoxy for a barrier coat, instead of Interprotect (but that's epoxy too, right?). The reason for that is that I know West System and never used Interprotect. What you need is a very good barrier coat... better than the original gelcoat because that turned out to be not good enough. I think when you would use West System for barrier coat, with the additives and the method they describe in their booklet, you get a barrier coat that isn't easy to beat by other products. It'll probably be the most expensive too, but it will last.

And don't forget, like the other poster wrote: the hull must dry out before putting on the barrier coat. After the gelcoat is removed, you should wash and rinse the hull like a madmen. If there were big blisters, I would pressure wash it daily for a week, then dry out for months or until a moisture-meter shows me it's okay. You can throw money at this for speeding it up, like using vacuum bagging to get the moisture out (might actually save money with todays yard-prices!).

If you mean the quick-fix, without removing the gelcoat, it wouldn't spend that much time, effort and money on the new barrier coat. I would fair it out, dry for a week, put two coats of Interprotect on, followed by the bottom paint. But I would do that only once. When this barriercoat fails, I would take the gelcoat off and go the whole way.

cheers,
Nick.

[s/v Jedi]

I found this photo while browsing for a photo for another thread and had to post it here. This is the best bottom job we ever had and the place was Peake's boatyard in Trinidad. The paint is Islands 44 plus, served us 3 years.

Click on the thumbnail for a better view.

cheers,
Nick.

[Stevens 47]

I peeled my bottom gel coat (purchased a gelplane for the job) then applied a penetrating epoxy followed by 7 coats of laminating epoxy all chemically bonded. Sanded with 80 grit then shot on 4 layers of high build epoxy primmer. Prior splash it will get another sand and more primer followed by bottom paint. As Nick says it is critical that the boat is dry, do not assume that it is just because its been out of the water for a month. It can take quiet a while for it to dry. If you can peel the bottom then let it sit all the better. Take some moisture readings before and then after the peel then keep testing until it is showing mostly dry. It took me 3 days to peel my 47 foot boat, that was 2 years ago and my neck is finally starting to straighten out. By the way I could not find a gelplane to rent in my neck of the woods, so had to purchase one.