Bottom Paint Question

[Futsal Fred]

My Hunter, which was previously in Long Island Sound, has maybe 8 or 10 coats of ablative bottom paint on it. Lots of chipped areas, really ugly and a mess.

So I've started taking it off with Soy Strip, a slow and miserable job but it's coming along.

Here's the thing: When I get all the blue paint off there's a thin layer of green scum remaining. I don't know if it's old staining or primer or a barrier coat or whatever, so I don't know what to do with it.

The boat is going to be exclusively in fresh water from now on and I wasn't planning on re painting if I don't have to.

Can some kind soul give me some advice here? What am I looking at and can/should I take it off or just plan on painting over it?

 

[Sailm8]

As a former lake sailor who has moved on to salt I really need to question why I spent the time and money on bottom paint. We only had slime in the lake and the paint didn't do a thing to keep it off no matter what I used. I would make sure I had a good barrier coat in order to fight blisters but have no idea why I spent 15 years painting. You have to ask yourself exactly what are you fighting?

In the salt water I have all kinds of stuff to keep off. Someone on this forum said they used Sears Weatherbeater house paint in a lake. If I this really works I would try it before I spend $150 on a gallon of paint.

 

[Alan]

If you are stripping the bottom why not try using PeelAway? It is easy to use and there is no hard elbow grease needed. I have used it to strip old paint and found it very effective.
If you are going to trailer sail your boat on fresh water you wont need either bottom paint or barrier coat. Just a good coat of wax will do. If the boat will be in the water most of the time then the barrier coat is a good idea.

 

[Rich Stidger]

I can't help with the paint-or-not-paint for lake usage, nor for the green stain. But regarding the flaking of the 8-10 coats of paint that you now have I offer the following-

I had a similar condition on my own boat and I believe it was due to the excessive application of paint over the years. The common "wisdom" is to put on a coat of paint for each year of use that you expect to achieve. I did that and ended up with a lot of paint that began flaking.

We sanded aggressively with 60 and 80 grit using a vacuum sander for four years to remove most of the paint. I tried a stripper but found that the work (not to mention the expense) was way too much to achieve the desired results.

But here is the key (IMHO)- each year we applied ONE very thin coat of paint using a 3/16" nap roller. A heavier roller will apply much more paint- stay away from the 3/8" or even 1/4" naps. My paint usage went from 6 quarts to under 4 quarts for my 40' sailboat. Now each year I lightly sand to scuff the surface and apply one fresh thin coat of paint. Most of the paint I apply each year wears off, thus I avoid the year-after-year buildup that caused the flaking problem. My anti-fouling performance has not changed with the thinner coats.

So if you are going to re-paint after stripping, I would suggest very thin coats.

One idea I do have about the green stain- there was a year that I had a brown stain that I removed with intensive scrubbing and power-washing. I believed it was due to the brackish water in which I was moored. Maybe that might be your source as well.

 

[SHADS]

You could try a diluted form of muratic acid [(10%) sorry about the spelling] to get the stain off. Just rinse it off after being on the boat for 1 minute.