Bottom Paint

[Tmacmi]

I'm looking for some tips for how to maintain modern bottom paints on fiberglass hulls in fresh water.

As a kid our wooden boat had red (copper) ablative bottom paint and was kept in salt water. Every year it came out and we sanded and painted the entire thing. (no face masks back then and my old man smoking a pack and a half a day)

Our boat came out of the water and I was surprised how good the bottom paint looked. It was also clear to me that the PO had only spot sanded the worst spots and painted them. He used Pettit Hydro Coat.

I don't know when the last time the bottom was stripped to the fiberglass and I don't know when the bottom was given a full top coat.

What is your experience? Do you sand and fairout the worst spots and give it a full top coat every year? Do you spot sand?

*note this boat is new to us and the first boat owned since I was 20.

[psk125]

Sounds like you need to sand & repaint the entire bottom to avoid the “measles” you noticed the PO was creating. Hydro Coat seems to work for where you keep the boat.

[Tmacmi]

Originally Posted by psk125

Sounds like you need to sand & repaint the entire bottom to avoid the “measles” you noticed the PO was creating. Hydro Coat seems to work for where you keep the boat.

A full strip to fiberglass? Or a strong sand of existing paint and broader fairing of trouble areas?

Also how does one sand bottom paint without damage to fiberglass?

[psk125]

Sand what’s there (you say it’s Hydro Coat) and fair trouble areas, and recoat. When (if) you get to fiberglass, stop sanding. Just like for your old wooden boat - you stopped sanding when you got to the wood, no?

[Boatguy30]

If it looks like a bunch of flaking and mess like and old porch, just painted over in a few spots. You need to strip it down. If it's relatively smooth and just a few areas have different paint. Just give the whole thing a light sand and another coat. Hydrocoat is actually not that soft and 1 should be fine for a summer.

FYI the Seahawk Monterey seems to be a somewhat better paint and will dry quicker and can get rained in sooner if weather isn't perfect

[Tmacmi]

Originally Posted by psk125

Sand what’s there (you say it’s Hydro Coat) and fair trouble areas, and recoat. When (if) you get to fiberglass, stop sanding. Just like for your old wooden boat - you stopped sanding when you got to the wood, no?

Well, yes in theory when you got the wood, you stopped. But wood is a little more forgiving than hitting gelcoat and getting through.

What grit paper do you use?

[deander]

Hi Folks,
I would appreciate some advice concerning bottom paint for my Orion 27. She's in the water for just a couple months at a time; out for a few months and back in again.
She's on the trailer when out of the water and freshwater trips are mixed in with salty ones.
Thanks for taking the time to respond!
Dean

[Boatguy30]

I would go with the Seahawks Monterey. It's very nice to work with and is relatively hard. The hydrocoat + does seem to work slightly better initially, but doesn't apply and well and I had a big rain shower after one coat and that caused some problemas with my coat build up. I waited an extra day before recoating and still have a bit of flaking in a few spots.

Overall, the Seahawk is a very nice paint to work with.

[HeavenBound]

Hi everyone, I’m new here and a seller just sent me pics of the new bottom paint. Looked great from a distance and I focused in and this is what I see (pics), like he just painted over the old with no sanding. Should I run?

[Jammer]

Looks pretty typical of boats around here. It isn't common to sand the hull until it's smooth because it's extra work and there's a risk of sanding through the barrier coat. Modern ablative bottom paints will adhere reasonably well to old paint.

[HeavenBound]

Hi Jammer, the seller had the boat in saltwater, I am moving it to a freshwater lake. Will there be issues do you think?

[HeavenBound]

Originally Posted by Jammer

Looks pretty typical of boats around here. It isn't common to sand the hull until it's smooth because it's extra work and there's a risk of sanding through the barrier coat. Modern ablative bottom paints will adhere reasonably well to old paint.

Hammer, I just found out he used flat exterior paint on it, says that is common (house flat) for trailered sailboats.???

[rslifkin]

Originally Posted by HeavenBound

Hammer, I just found out he used flat exterior paint on it, says that is common (house flat) for trailered sailboats.???

In that case, I'd consider the previous guy to be an idiot. And I'd plan to strip the bottom completely and re-paint with whatever paint you decide is most suitable for your usage and location.

[barnakiel]

I do not sand. Wash with hard fresh water then dry. Paint over.


b.

[rslifkin]

Originally Posted by barnakiel

I do not sand. Wash with hard fresh water then dry. Paint over.

For most ablatives, this is correct. Just get it good and clean and you can throw a fresh coat on. I only sand to smooth out any chips or rough spots a bit.