Hull sanding or ?

[Maine Sail]

It is my experience that ablative paint does build up and therefore does start to flake off when it gets too thick. I was advised by my surveyor to "sail some off" by skipping a year. I did just a band around the water line and the top of the rudder last year and the paint on the hull seems diminished. It also started to chip quite a bit more, hopefully making it easier to do a bottom job this year. The ablative I typically use, Pettit Hydrocoat, says it will go two years and from now on that is my plan. Two years with just the waterline done the second year. I don't like to paint the bottom. It's not fun. She will be a little less uniform the second year, but perhaps I'll have some fun and write "paint me" on the hull so folks can see it when the rails down LOL.

Bob,

This is a mistake many make when switching to an ablative. You don't want to paint it every year to avoid the build up. I put only two coats on last year after the bottom job one red (hot-coated) and one black. I only have a couple of spots where I can see red. I will touch those up with a West Systems foam roller, to keep it thin, and continue for this season..

 

[jcastle]

These are all great posts with a bunch of information.

There are several ways to go about this depending on what you are trying to accomplish from a time and money standpoint.

The easiest and most economical way would be to sand the boat with 80 grit. You can spend more time in the areas that have the build up or have been flaking. Then apply bottom paint. Done.

If you want to get more aggressive with the sanding, and remove all of the bottom paint, then I would recommend putting on a coat of epoxy barrier coat, like (Tuff Stuff from Sea Hawk Paints). Then bottom paint.

If sanding is not a choice for you, then you can use a marine paint stripper. It will take off the bottom paint without harming the barrier coat, or the gelcoat. However, you still need to scuff sand with 80 grit before bottom painting.

If the barrier coat is not in that great of condition, you might consider having the bottom soda blasting done to gelcoat and starting with a new barrier coat system and bottom paint. $$$$

As stated in previous posts, using the first coat of bottom paint in a contrasting color from the final coat of bottom paint is a great way to determine when you need to paint in the future, and avoiding excessive buildup. I would stick with ablative bottom paint.

Tuff Stuff Epoxy Barrier Coat
Ablative Bottom Paint
Marine Paint Stripper