Can you paint below the water line with automotive primer and cheap spray paint?

[andrewbabich]

Can you paint below the water line with automotive primer and cheap spray paint?

I was given this 1978 tri hull that served as a recreational lobster boat in the water for a while. It has a couple layers of degraded paint under the water line. I see white fiberglass, some kind of greenish paint and then a cracked old red orange paint on the layer. I sanded it down with 60 grit to clean it up (didn't get nearly all the old paint off) wiped it down with alchohol and then I rattle can sprayed it with primer. Is it going to come off? What is the correct type of paint and how much does in normally cost?

 

[Star]

Re: Can you paint below the water line with automotive primer and cheap spray paint?

Sanding the bottom of your boat with 60 grit sandpaper is not a good thing. you will probably damage the gelcoat! Protection of a Fiberglass hull in salt water all season is no easy task. Epoxy is probably your best bet, but antifouling is also an issue. Do realize that the material you use can affect your top speed, so do your research and pay good money for your boats life and performance.

 

[jigngrub]

Re: Can you paint below the water line with automotive primer and cheap spray paint?

If you didn't remove all the old paint, whatever you put on there is going to come off too.

It's pretty simple, do the job right the first time and you won't have to worry about it.

 

[ondarvr]

Re: Can you paint below the water line with automotive primer and cheap spray paint?

If you are going to do a low cost paint job then skip the primer, and rattle cans aren't cheap, plus they are low quality, buy a quart or two Rustolium.

60 grit won't hurt the gel coat and you don't need epoxy, nor do you need an anti fouling paint unless you plan to leave the boat in the water.

 

[andrewbabich]

Re: Can you paint below the water line with automotive primer and cheap spray paint?

Good call. I'm only trying to make it not look like a total eyesore first. I only painted the below the waterline area of the sides of the boat. The bottom still looks all green and gross. I wonder how much drag old crummy bottoms cause on boats?

 

[oops!]

Re: Can you paint below the water line with automotive primer and cheap spray paint?

lots andrew......antifouling paint can take between 2-5 mph off the top end, depending on several factors including the size and weight of the boat..

as ondarvr said, you only use anti fouling if the boat is staying in the water.....i think that is what the green stuff is.

prep is the key to any good paint job.....in your case....the prep will be getting the old stuff off because as said earlier....it will just flake off, as yoiu are bonding to the old paint. and that bond is failing.