Seeking Bottom Paint Advice

[IOLANI]

The time is finally approaching to start readying the boat to splash in April. Since purchasing the boat 4 years ago I have been paying the yard to power wash, scrape and apply a fresh coat of bottom paint each spring and have been very happy with the results (Petit Odyssey). The bottom paint from last spring still looks pretty darn nice like maybe I could get away with just touch up in certain areas.
I'm not concerned about the expense the yard does a nice job for a reasonable price and I'm perfectly willing to lay on another full coat. I'm really wondering when does it reach the point of "too many coats" applied where it requires blasting back down to the glass and starting over ?

 

[jim rosenthal]

That depends on what type of paint you are using. Ablative paints, which is what just about all of us use, wear away as part of their protection activity, so you don't end up with buildup of the paint to the point where you have to have the hull blasted- at least not very often. I use an ablative paint (SeaHawk Cukote) and there have been several years when I just had it touched up and repainted the waterline.

I use zinc spray on the running gear and have had good luck with that. For the price, it is difficult to beat.

 

[brettportzer]

There can definitely be that point though… The bottom paint on my boat was architectural when I bought it… Seriously needed to be blasted and redone from scratch, which I did.
Granted, I am in freshwater, but, I believe I did the full bottom paint 4 yrs ago with Fiberglass Bottomkote NT, and I did a coat of red and then two coats of blue.
Other than water line touchups, I haven’t done any below the waterline touchups yet.
I will probably do some this year, possibly sand it back a bit, but there isn’t much red showing through really yet.

 

[Sonic Boom]

That depends on what type of paint you are using. Ablative paints, which is what just about all of us use, wear away as part of their protection activity, so you don't end up with buildup of the paint to the point where you have to have the hull blasted- at least not very often. I use an ablative paint (SeaHawk Cukote) and there have been several years when I just had it touched up and repainted the waterline.

I use zinc spray on the running gear and have had good luck with that. For the price, it is difficult to beat.

The SeaHawk Cukote has performed better for us in the Chesapeake Bay than other options. Not sure how much difference geographic location makes

 

[jim rosenthal]

Over years, there have been various bottom paint tests, but I have never seen one that specifically addressed the question of which bottom paint performed best in each locale, although I seem to recall some discussion of it in Powerboat Reports, which sadly is no longer published. There is probably some information in Practical Sailor, but that doesn't help us much as our boats operate in a speed range different from that of sailboats. The best alternative seems to be to ask around in your respective area and find out who is using what, and how well it's working on their boat. Tests of bottom paints to look at the above question are time-consuming and expensive, and I haven't seen one in a long time.

It's difficult sometimes to switch bottom paints- there can be adhesion issues between different brands and there's no guarantee that a new bottom paint will stick to what's left of the old, even if the paint types are similar. So if you are lucky enough to find a paint that works well where you are, perhaps the prudent thing to do is stick with it as long as you can, unless you are willing to bet the cost of a bottom job on a different paint. That's an expensive wager, and I have avoided doing it.

I agree that even ablative paints can build up to the point where the residue needs to be removed. The best method of removal would be dry ice blasting but that isn't always available. Walnut shell blasting is also effective. I have avoided glass bead or sand blasting; I think they are too aggressive and can damage the bottom (your experience may differ) I have seen what can be done with dry ice blasting and it is pretty amazing how well it is able to remove old paint, dirt, etc, while leaving the bottom itself undisturbed.

 

[IOLANI]

It's difficult sometimes to switch bottom paints- there can be adhesion issues between different brands and there's no guarantee that a new bottom paint will stick to what's left of the old, even if the paint types are similar. So if you are lucky enough to find a paint that works well where you are, perhaps the prudent thing to do is stick with it as long as you can, unless you are willing to bet the cost of a bottom job on a different paint. That's an expensive wager, and I have avoided doing it.

I agree that even ablative paints can build up to the point where the residue needs to be removed. The best method of removal would be dry ice blasting but that isn't always available. Walnut shell blasting is also effective. I have avoided glass bead or sand blasting; I think they are too aggressive and can damage the bottom (your experience may differ) I have seen what can be done with dry ice blasting and it is pretty amazing how well it is able to remove old paint, dirt, etc, while leaving the bottom itself undisturbed.

Thanks guys for all the input. The prior owner used Pettit Odyssey HD Ablative and the bottom looks great so I have continued to use it. The props, shafts, and struts have never been painted since new and also look great so I have continued that practice also. I'll put on another coat this year and put off worrying about the build up until it becomes an issue.

 

[osprey]

The props shafts and struts have never been painted????? are you in fresh water?

 

[carolinacoast]

Just had petit prop coat paint applied to my metals/props instead of prop speed. It is much less expensive and yard said results for slow boats has been good. Will see how it goes with the diver.

 

[carolinacoast]

Using Seahawk biocop for the first time also. Cukote was my goto when the cuprous oxide was 60%. EPA reduced it to 47% or so. Biocop has 2 biocides. Will see how it performs. We have a lot of growth when it warms up.

 

[IOLANI]

The props shafts and struts have never been painted????? are you in fresh water?

I need to correct myself the struts have been painted but not the shafts.

 

[osprey]

How do you keep your props and shafts clean? Mine would be reefs in no time.

Have a Nice day

 

[IOLANI]

How do you keep your props and shafts clean? Mine would be reefs in no time.

Have a Nice day

Maybe due to the fact the current is pretty swift where I keep her at the mouth of the canal. I ran the boat a lot the prior year so that probably helps. I did find a photo from 3 years ago that showed the props and struts painted but last year just the struts. The paint don't stay long on the props anyway.
The only real problem area I have for barnacles is the trim tab plates they get loaded on the bottom.

 

[Joe Hewes]

I had my boat blasted (baking soda) last year. (See pics) I estimate it had been 15 years since it was last done based on the condition & thickness of the paint. Ive owned the boat for 4 years - and have it hauled annually & painted/ touched up as needed. I had a lot of crazing & sections that would no longer adhere. I knew it was time!

Upon completion of the stripping process the bottom was faired & sealed with epoxy barrier coat. Fortunately we had no blisters or damage.

We picked up a couple of knots in speed & a few hundred RPMs. Mostly I gained piece of mind knowing the bottom is in great shape & we now have a base line….

We too use Sea Hawk BioCop. I’ve gotten great performance from the paint. We use Prop Speed on the shafts, struts & props. Expensive but it works as long as your diver doesn’t scrape it off or you do some dredging!

 

[SKYCHENEY]

Great looking YF. What is the davit you have up top? Looks nice and small. Must be telescoping.

 

[Joe Hewes]

That’s a Steel Head 1000 & yes, it is telescopic.

 

[jim rosenthal]

The zinc spray you get from Rustoleum works fine on underwater running gear. The CRC zinc spray also works fine. I do three coats. (I think the above items cost less per can than Pettit's product, but seem to work the same.

 

[Briankinley2004]

The zinc spray you get from Rustoleum works fine on underwater running gear. The CRC zinc spray also works fine. I do three coats. (I think the above items cost less per can than Pettit's product, but seem to work the same.

I use ZRC and apply with a chip brush. You get a heavier coating and it has a higher percent of zinc than the sprays

Edit to add you have to take it down to bare metal for this product per the manufacturer

QUART CANS GALVILITE

Galvilite can be used without topcoat in place of and for repair of hot-dip galvanizing.

store.zrcworldwide.com