Bottom paint maintenance on boat permanently in marina

[thebrushand]

Hi, just spent an hour fruitlessly looking through the search results for an opinion on bottom paint maintenance. Our project is basically covered up and permanently bobbing in a dock in SF. Last June it was completely repainted from bare, the bottom had 3 good coats of ablative paint.

It was cleaned in June (one year on), absolutely nothing of note to report from the diver. We are now at that time when we are thinking about maintenance. We will be touching up and recoating topsides / masts just to keep everything up to scratch, but what about the bottom?

Seeing as it is not being sailed, my instinct as a painter, not a sailor, says that because the paint wears away under the wear and tear of being sailed, and seeing as this is unfortunately not the case since being painted, the bottom paint should be pretty much intact. The wear and tear from a careful diver shouldnt compromise the bottom paint before hauling out in the Spring, ie about 20 months.

But that is just my gut theory. Does that sound right based on others real life experience. If we keep the diver on a 3 month maintenance program until next Spring and haul out then to bottom paint, should we be OK.

What do the pros reckon.

Thanks

[jonboy]

Get the bottom-inspecting/cleaning diver to use no scrapers or abrasives... a good stiff household scrubbing brush will 'clean' the hull without paint damage, but it won't remove stubborn barnacles and limpets...You seem maintenance -oriented, so regular inspections are on the cards...Unless your marina is in a particularly aggressive environment I wouldn't worry at all until the next haul-out.

[ron ll]

Depending on how you feel about rules and the environment, you might want to check with someone about scrubbing ablative paint in the marina. At Shilshole Marina, it is prohibited and anytime I am scrubbing my bootstripe and the brush hits the bottom paint, clouds of red appear in the water. If you are a scoflaw, do it when no one is around. If you are a fine upstanding law-abiding citizen, you might want to check. :)

I am seriously thinking about changing to a hard bottom paint on next haulout just for this reason.

[donald branscom]

Hi, just spent an hour fruitlessly looking through the search results for an opinion on bottom paint maintenance. Our project is basically covered up and permanently bobbing in a dock in SF. Last June it was completely repainted from bare, the bottom had 3 good coats of ablative paint.

It was cleaned in June (one year on), absolutely nothing of note to report from the diver. We are now at that time when we are thinking about maintenance. We will be touching up and recoating topsides / masts just to keep everything up to scratch, but what about the bottom?

Seeing as it is not being sailed, my instinct as a painter, not a sailor, says that because the paint wears away under the wear and tear of being sailed, and seeing as this is unfortunately not the case since being painted, the bottom paint should be pretty much intact. The wear and tear from a careful diver shouldnt compromise the bottom paint before hauling out in the Spring, ie about 20 months.

But that is just my gut theory. Does that sound right based on others real life experience. If we keep the diver on a 3 month maintenance program until next Spring and haul out then to bottom paint, should we be OK.

What do the pros reckon.

Thanks

You are correct about the bottom paint.
If it is sitting at the dock do not do anything to it.
If you have a diver clean it, then stuff will just grow faster because some the the bottom paint comes off with the scrubbing. But have a diver check those zincs each year because in a marina the boat can get close to the bottom where there is more electrolytic action with stagnant water.

I lived on a boat in SF bay for 14 years and did all the maintenance of my boat.

[thebrushand]

thanks for those reassuring replies

[TimH]

There is a device I have seen people use at my marina. Its a long handle made from PVC pipe with a curved handle and T on the end. The cross piece has a chunk of astroturf attached to it so as to act as a brush. You can get way down to the bottom of a keel on a 20 footer or so with ease.

[donald branscom]

Hi, just spent an hour fruitlessly looking through the search results for an opinion on bottom paint maintenance. Our project is basically covered up and permanently bobbing in a dock in SF. Last June it was completely repainted from bare, the bottom had 3 good coats of ablative paint.

It was cleaned in June (one year on), absolutely nothing of note to report from the diver. We are now at that time when we are thinking about maintenance. We will be touching up and recoating topsides / masts just to keep everything up to scratch, but what about the bottom?

Seeing as it is not being sailed, my instinct as a painter, not a sailor, says that because the paint wears away under the wear and tear of being sailed, and seeing as this is unfortunately not the case since being painted, the bottom paint should be pretty much intact. The wear and tear from a careful diver shouldnt compromise the bottom paint before hauling out in the Spring, ie about 20 months.

But that is just my gut theory. Does that sound right based on others real life experience. If we keep the diver on a 3 month maintenance program until next Spring and haul out then to bottom paint, should we be OK.

What do the pros reckon.

Thanks

PROS???? They will recommend a full scrape down and complete PRO paint job!!
Divers want to earn money too.

If you put the bottom paint on and it sits in the marina you should do nothing.
Each time you clean it more growth will occur. You will see that right after a diver cleans the boat the growth occurs at a faster rate. YOU WILL have to replace the zinks every year anyway. OK every 1.5 years MAX. The amount of time bottom paint lasts varies with type of hull material,location,type of paint, and conditions of the marina etc.,. With wood boats worms are a concern too.

THE BEST information that you can get is from other boat owners in your marina.

Growth on a boat starts immediately after cleaning.
Talk to live aboards in your marina. They know a lot because they are there and hear all the reports from the boat yard because they often work on boats in the area.

[Peter Malcolm Jardine]

For the most part, bottom paint uses cuprous oxide as the anti fouling element. The cuprous oxide leaches out through the binder (the "paint") until it is exhausted, at which point the antifouling protection is gone. The remaining paint needs to be removed and/or overcoated to renew protection. Generally, several layers build up after renewed coats of paint, and finally adhesion starts to break down on the buildup of paint, and flaking starts to happen.

Having a couple of layers on a wooden boat isn't a bad thing, but don't mistake paint for antifouling protection. There are various other components in some bottom paints that are anti slime and so on, but cuprous oxide based bottom paints rarely last more than about 9 months per application. Cold, moving water is the only natural antifouling environment. Stagnant, warm water in most marinas is the perfect habitat for algae and other forms of growth

[redbopeep]

Agree with Peter. Bottom paint not only has life related to ablation/wear from sailing or scrubbing it ALSO has a life related to the chemistry of the anti fouling materials.

Suggest that you do what responsible boat owners everywhere do--find out the expected life of your bottom paint and haul out/repaint based on that schedule. Most ablative paints don't last very long and it would be reasonable for you to expect to haul out and repaint every 1 to 3 years depending on the paint and your tolerance for things growing on your hull that can damage your hull.

As I recall, you did a lot of work to your boat recently and I would think that you'd want to keep her in good shape and ready to go sailing. I also thought you were planning on cruising with your boat? Did your plans change so that you're not cruising nor sailing?

How did your work turn out? Hows the boat? What kind of bottom paint did you end up using, btw?

[thebrushand]

There is a device I have seen people use at my marina. Its a long handle made from PVC pipe with a curved handle and T on the end. The cross piece has a chunk of astroturf attached to it so as to act as a brush. You can get way down to the bottom of a keel on a 20 footer or so with ease.
We used something similar from our ingenious neighbour in the marina, removed the worst of the slime, told the diver not to scrape, just check the zincs regularly, some periodic brushing off, and we will haul out next Spring and put some more bottom paint on then. Not much option but to nurture it along till then.

All being well, throwing a few more bucks at the project, the boat will be close to sailing by then too, fancy that, a sail boat that sails! No kidding, it has been akin to standing in a cold shower stuffing money down the plug hole, but money cant buy the great lifestyle at the end of the shower, can it!

[jclays]

I have a 30ft power boat. My diver cleans my hull monthly and gives me a written report. I use 2 coats of Trinidad paint on the bottom of my boat and get up to 3 years between haul outs. Two years on the average.
Jim