Bottom Paint and Anodes for Fresh and Salt Water

[Howler]

We are beginning to plan a several month cruise out of Lake Ontario via the St. Lawrence Seaway, around the Gaspé Peninsula, down the coast of Nova Scotia, and across to Maine (aka the Downeast Loop).

The initial part this trip is in fresh water and the latter part is in salt water. The sacrificial anodes need to be different material. Is it OK to put salt water anodes on for the whole trip to avoid hauling out part way?

Similar question for bottom paint. We use VC17 on the Great Lakes. I assume we’d need salt water bottom paint. Is it OK to use that during the fresh water part of the journey? Also, is there a salt water paint that can be applied over VC17 or do you need to sand down to gel coat and start from scratch?

Thanks!

[rslifkin]

For the downeast loop, there's a good chance you could get away with just leaving the VC-17 on. It's in reasonably cold water, so that will reduce growth. VC-17 won't fail in salt water or anything, it's just not the most effective antifouling (so you'd need to get the bottom cleaned sooner than you otherwise would, but that can be done by a diver). I'm not sure there's much that'll stick over VC-17, so unless you want to change paints long term, I'm not sure swapping paints will be worth it for a 1 time trip.

If you do want to switch paints, the majority of bottom paints people would use in salt water will work fine in fresh (only exception I know of is Micron 66). Personally I'm using Micron CSC, although I'm not as sure what I'd choose if starting with a blank hull.

For anodes, I'd use aluminum (navalloy). They're fine in salt water, and I've found mine to work fine in Lake Ontario as well (so I've felt no reason to switch to magnesium). We're not in clean enough fresh water to need magnesium anodes on most boats, although if you have an aluminum saildrive that may have somewhat stricter needs than a bronze / stainless shaft drive. Unlike zinc anodes, the aluminum / navalloy ones don't crust over in fresh water, so no issue switching water types with them.

[Pete7]

Originally Posted by rslifkin

I'm not sure there's much that'll stick over VC-17, so unless you want to change paints long term, I'm not sure swapping paints will be worth it for a 1 time trip.

Been there and got the T shirt, had to strip the VC17 off as the paint I put on top failed completely. A right palaver in time and money to sort.

Pete

[Howler]

Originally Posted by rslifkin

For the downeast loop, there's a good chance you could get away with just leaving the VC-17 on. It's in reasonably cold water, so that will reduce growth. VC-17 won't fail in salt water or anything, it's just not the most effective antifouling (so you'd need to get the bottom cleaned sooner than you otherwise would, but that can be done by a diver). I'm not sure there's much that'll stick over VC-17, so unless you want to change paints long term, I'm not sure swapping paints will be worth it for a 1 time trip.

If you do want to switch paints, the majority of bottom paints people would use in salt water will work fine in fresh (only exception I know of is Micron 66). Personally I'm using Micron CSC, although I'm not as sure what I'd choose if starting with a blank hull.

For anodes, I'd use aluminum (navalloy). They're fine in salt water, and I've found mine to work fine in Lake Ontario as well (so I've felt no reason to switch to magnesium). We're not in clean enough fresh water to need magnesium anodes on most boats, although if you have an aluminum saildrive that may have somewhat stricter needs than a bronze / stainless shaft drive. Unlike zinc anodes, the aluminum / navalloy ones don't crust over in fresh water, so no issue switching water types with them.

Thank you!

[capt jgw]

If you do switch paints, the VC will have to be removed completely. It's got Teflon in it like a non stick frying pan, so nothing will stick to it. Fortunately it goes on really thin so 120 grit paper on a DA sander makes pretty short work of it.

[Kd9truck]

Originally Posted by capt jgw

If you do switch paints, the VC will have to be removed completely. It's got Teflon in it like a non stick frying pan, so nothing will stick to it. Fortunately it goes on really thin so 120 grit paper on a DA sander makes pretty short work of it.

Hey, “if nothing will stick to it” then why should he take/sand it off? I have yet to find a paint that does that, kind of the point of bottom paint no?

[rslifkin]

Originally Posted by Kd9truck

Hey, “if nothing will stick to it” then why should he take/sand it off? I have yet to find a paint that does that, kind of the point of bottom paint no?

Unfortunately the "nothing will stick to it" only extends to other paints, not so much bottom growth.