When to strip bottom paint

[UNCIVILIZED]

On a bigger boat, or one that's a problem child, it might be worth looking at having it media blasted, in order to fully strip it. You'd need to check around to determine the costs of such, as they can vary widely with location & available services. But if it can be done for a reasonable figure, & the guys know their trade, then it's a no brainer.

You actually can strip a good sized boat in a (long) weekend, using a grinder. I've done 40' tri's in that time span, so 3 hulls. Though admittedly I was working on boats full time then, & lived with my grinder & respirator. So, yep, skills.
And were the OP keeping the boat, then I'd say yes, strip it. But for short term ownership, feather the owies, rough things up, & repaint.

A bottom job, including full stripping definitely does improve performance. And on a 30'-35' boat, 500lbs is huge. As is having a smooth, fair bottom Small Things Big Wins

[David B]

Originally Posted by cnsutter

I need advice on when you need to strip the bottom rather than just prepping and applying a new coat. I am a new owner of a 1978 O'day 30 and she needs some new paint before next season (New England waters). I was inspecting the current bottom and its definitely chipping and flaking off in pretty large pieces. Its clear that it has been painted over many many times. Especially the leading edge of the keel has large pieces separated and I'm not sure how to tell how far down the flakes are (just paint, gelcoat, etc.).

The rest of the story:
This is my first boat and the intent all along was only to have it for 2 years as a learner boat before stepping up to something larger/nicer. Having said that, this means that I don't want to invest any more money into the boat than I have to since I am planning on selling it after the season is done next year. Is it acceptable to just scrape/prep what is there and apply a new coat? Really I am asking at what point in time it has to come off or else you risk damaging the gelcoat and fiberglass?

Thanks in advance.

I found a lot of advice on how to strip/paint the bottoms, but not so much on when to do it. At my yard, all the bottom paint work must be done by their guys. I am afraid to get their opinion since they are almost certainly going to say I should fully strip and barrier coat it.

For the time you are keeping it, I suggest you hit it hard with a pressure washer, and then let dry out. Ideally, then give it another hit (or just go over gently to get the still-flaking bits off), then, and if not more is coming off, let it dry, then slap some more antifouling paint on it, and enjoy your boat. The gelcoat underneath will be fine, and if it has an epoxy barrier coat between the gel and the antifouling, then so much the better.

We have a little 22 footer that had years of build up on it, but the difference was we were going to keep her for the foreseeable, and after all the hassle of getting the many flaky layers off, did not want to go through all that ever again, so went with Coppercoat (never looked back since then). But for you, slap more on and go sailing. You will be surprised how quickly you get a feel for it all, and how much information you gain to help you decide on your next boat.

Enjoy, and I hope you have a great Summer up there (ours down here is still coming).

David

[foufou]

What about soda blasting? I have read that's the way to get the bottom paint off. I got a quote for $1000 US for a 27' boat

[ramblinrod]

Originally Posted by cnsutter

I need advice on when you need to strip the bottom rather than just prepping and applying a new coat. I am a new owner of a 1978 O'day 30 and she needs some new paint before next season (New England waters). I was inspecting the current bottom and its definitely chipping and flaking off in pretty large pieces. Its clear that it has been painted over many many times. Especially the leading edge of the keel has large pieces separated and I'm not sure how to tell how far down the flakes are (just paint, gelcoat, etc.).

The rest of the story:
This is my first boat and the intent all along was only to have it for 2 years as a learner boat before stepping up to something larger/nicer. Having said that, this means that I don't want to invest any more money into the boat than I have to since I am planning on selling it after the season is done next year. Is it acceptable to just scrape/prep what is there and apply a new coat? Really I am asking at what point in time it has to come off or else you risk damaging the gelcoat and fiberglass?

Thanks in advance.

I found a lot of advice on how to strip/paint the bottoms, but not so much on when to do it. At my yard, all the bottom paint work must be done by their guys. I am afraid to get their opinion since they are almost certainly going to say I should fully strip and barrier coat it.

The answer to your question is...

...there is no hard and fast rule.

If the adhesion of the current anti-fouling paint is failing and big hunks are falling off, the bottom needs to be redone.

If you don't want to do what needs to be done, well, it's your boat.

You don't have to anti-foul at all; you can just live with the eco system that grows on the bottom.

Things you should consider are:

1. Non anti-fouled areas will be subject to organism attachment and gelcoat damage.
2. Applying fresh anti-foul paint to failing anti-foul paint is a waste (it can't do any good if it falls off).
3. To have the yard strip and repaint the boat could cost $1.5K-$3K depending on the quality of work they do.
4. A good bottom may add value at sell time and make it easier to sell, but you won't likely recover all of the cost.
5. A good bottom is faster.

I would consider the current value of the boat. Is it in pristine condition other than the bottom? If so, do the bottom, it would be a shame to devalue the boat because the bottom is crap. If the boat is in terrible general condition, leave the bottom, you have too many other issues to worry about. No point in trying to make a silk purse from a sow's ear, and you'll have way too much money tied up in the boat.