Another Bottom Paint Thread

[markpj23]

OK so I've got the Practical Sailor issue with their bottom paint results. I am leaning towards the Interlux Fiberglass Bottomkote since it has an anti-slime agent and its cost is reasonable.

So off I go to use the calculators that help me decide how many gallons I'll need. Varied results but to be safe I'll get 5 gallons for 2 coats (52ft * 15ft *.85) and maybe a 3rd around the waterline.

Problem is - I have NO idea what paint was used by the PO. It's red and hard and it's apparently paint since it stayed on for 18 months. I think he did a single coat with a dry roller...

So - how do I know what prep work I need to do? I've read some threads that say DON'T sand the old paint. Some say use a chemical prep.

So which is correct? If the old paint is not coming off, can I just cover it? And how many coats can you use before you have to remove the old layers?

[Pblais]

If it's hard then ablative covers hard but not the other way around. Powerwash then scrape, then see about light sanding any place that seems the least bit loose. Scape all barnacles all the way off. With ablative you may not need to remove it very often. Two coats may go 2 years depending on the paint.

[Charlie]

I have the same question Mark. My thought is to contact the previous owner and see if he remembers. I am luck in that I know the yard that did the work. My paint is black with a red stripe (that is actual anti fouling paint) around the waterline.