Bottom Paint Maintenance

[sailorduff]

Hey I'm looking for some advice on bottom painting, heres the story: My boat a 37' endeavor, has been in dry dock for over a year, Im want to splash her in a month. I need to do a few things in the boat yard including some bottom painting. I just redid the whole bottom in 2009, but I know since it's been outta the water for so long that the properties of the bottom paint may wear off...so do you guys think I should scuff up and repaint the whole bottom? if so how many coats? After scuffing up and giving it a good rinse is there any kind of solvent wash I should use to make sure all the dirt is off?

Any and all tips appreciated! Thanks!

[Fstbttms]

Originally Posted by sailorduff

...so do you guys think I should scuff up and repaint the whole bottom?

Yes.

Originally Posted by sailorduff

if so how many coats?

Two. Three at the waterline and leading/trailing edges.

[Minnewaska]

Yes, definitely will need recoating.

Compatibility is very important, if you are not using exactly the same paint as you did two years ago.

You might want to consider whether it is a good time to change to an environmentally friendly bottom paint. I'm no tree hugger, but think we will all end up there sooner or later. In some cases, you can apply the same manufacturer's environ friendly paint over top of their regular. If you slightly change colors, you would even be able to use your old scuffed paint as a signal layer that your primary barrier is wearing thin.

[BubbleheadMd]

This is a great guide to surface prep and application of antifouling paints, but Interlux. Scroll down to page 23 of 36. It's a matrix showing which kinds of paints will adhere to old paints and what kind of surface prep is required.

"Like" paints will adhere to each other with less surface prep. (Less work for you)

If you use an ablative paint, I recommend you use a different color than what is already on your hull. When the previous color starts showing through, you have a visual indicator that it's time to haul and re-paint.

Interlux

[sailingfool]

Don't just put more paint on...you should figure out whether you need new paint before you put any on.

Each time you put paint on the bottom you increase its thickness...in you get a buildup of paint at some point the paint starts to chip and you will face stripping the entire bottom to get back to a good finish. Avoid paint buildup at all costs (or specifically, the cost of sandblasting your bottom...).

You need to figure out what paint is on the bottom and what the properties of that paint are. Based on the type of paint, you MAY want to put a coat on. See what Interluux has to say on bottom paint here http://www.yachtpaint.com/Literature...10-usa-eng.pdf (Opps, same link as BubbleheadMD!).. If you are unsure of the properties of the paint, contact the manufacturer for advice. I have found folks like Interlux support to be very helpful and expert about their stuff.

If you determine you have a multi-season ablative paint, touch up any spots showing wear and if the boat had been in use for a full season do one coat. The best way to clean the bottom is to power wash it, most yards will provide this service.

[Fstbttms]

Originally Posted by sailingfool

Don't just put more paint on...you should figure out whether you need new paint before you put any on.

His boat has been out of the water for more than a year. Trust me- he needs new paint.

[sailingfool]

Originally Posted by Fstbttms

His boat has been out of the water for more than a year. Trust me- he needs new paint.

If the paint is a multi-season ablative, why would he necessarily need to paint?

Here's a note from my preferred paint (Micron Extra with Biolux Antifouling Boat Paint | Interlux) : "Haul and re-launch without repainting..."

This has worked for me...

[Fstbttms]

Originally Posted by sailingfool

If the paint is a multi-season ablative, why would he necessarily need to paint?

No paint that I'm aware of can withstand the kind of time out of the water the OP's has.