In the water cleaning with ablative paint

[PamlicoTraveler]

Are there any bottom paint experts that can opine on this? I did bottom paint last year and the boat has been in the water since. I can get a diver anytime to clean off the gunk and I am wondering myself when that is advisable. I don't want to scrape off the ablative paint.

So far I don't see barnacles - more or less just slime. What do the paint companies advise? At what point should I start to scrape?

[hellosailor]

If there's just slime on the boat, why would you even think about scraping?

A sponge might take it off, if necessary a soft ScotchBrite pad. Just enough force to remove the "grass", leaving the paint on the hull. No?

[PamlicoTraveler]

Probably correct. Even a Scotchpad would seem take off the paint, so I'm wondering if I should even do that. I just see everybody around me having divers all the time and I'm thinking I don't want to do that.

So you're correct and I guess I am musing out loud.

[gamayun]

Do you ever move your boat? If you have ablative paint, then whatever you use, you're going to have a cloud of paint in the water when it's wiped. I'm a diver and clean my own boat. I don't do it as a business so I can be fussy about it. When I bought my boat, they had used ablative paint, which is meant to come off (ablate) when the boat is moving along in the water. I didn't like it so the next haul out, I removed all bottom paint and put on Pettit Trinidad, a hard (semi-hard?) paint. I just hauled again after nearly two years of frequent cleanings (4-6 weeks was usual because of racing schedule) but I also went 6 months and it was still only light slime. Everyone remarked at how good the bottom still was. I use a soft (!) shop cloth and a light touch. Now, the conditions might also vary depending on locale and salinity. I'm in the cold (50s-60s) waters of San Francisco Bay with more freshwater influence being in the Oakland estuary. Other places, the tenacity of barnacles might be different, but a good diver ought to know your boat and at least give you feedback on what they find after x months without a cleaning. You could ask the other divers you see on the docks about this. After cleaning some boats for friends, I don't think they're all the same. If you need to scrape, it's my opinion that your bottom paint is now failing and it's ready for a haul out. These are just my personal observations. Others in other locations are likely to be different.

[a64pilot]

Originally Posted by PamlicoTraveler

Probably correct. Even a Scotchpad would seem take off the paint, so I'm wondering if I should even do that. I just see everybody around me having divers all the time and I'm thinking I don't want to do that.

So you're correct and I guess I am musing out loud.

The green scotchbite or the red will eat it for sure. There are many grades of scotchbite usually graded by color.
There is a white one that I use, comes with a handle like a brush. It’s so gentle that you can scrub your arm with it and it won’t scratch, that is sort of the test for me, if it can scratch skin, it’s too abrasive for slime.
A plastic dry wall knife is cheap and works on light hard growth

[hellosailor]

"Even a Scotchpad would seem take off the paint,"
Remember, that paint is supposed to get scrubbed off by just the normal flow of water past your hull. So yes, anything "harder" than water is certainly going to scrub it.
As A64 mentions there are all sorts of "scotchbright" pads with equivalent "grits" from something like 50 to 2000, color coded.
Or, you could take the boat out for 24 hours in heavy wind, that should give you enough speed to "hose it off".

[skipgundlach]

We have ablative paint. We sit (dammit) most of the time in the incredibly fecund ICW at Vero Beach, and we grow junk that we have a diver remove before we leave the mooring (also dammit, but there's not much alternative in Vero), including, and in particular, the prop.

When we're in the Bahamas and likewise not moving much at all (really short hops between islands or in MHH for sometimes weeks), we find a nice grade sandbar and ground on a mid-falling tide.

I go over with a compressor and hookah, and use a deck brush on the grass. Any time we actually sail somewhere (e.g. we came off a similarly horrible place in Saint Simons Island GA to MIA, and it was whistle-clean) the bottom takes care of itself...

[Halien]

Washington State has a "no visible plume" law, so you can't clean hulls in the water if they have ablative paint. Professional divers who care about their businesses won't do it. The fines are large. I guess you could jump in the water and do it yourself. If I saw you doing that I'd turn you in. Compliance costs at marinas and boatyards here are not insignificant, and they get passed along to everyone, including folks who chose to follow the rules.

[Windcall]

I've found scraping takes off less paint gets the stray barnacles too. We are in Vero too, got to get new scrapers and floats lost a bucket of them in New London the River Nymphs didn't give them back.

[skipgundlach]

Originally Posted by Windcall

I've found scraping takes off less paint gets the stray barnacles too. We are in Vero too, got to get new scrapers and floats lost a bucket of them in New London the River Nymphs didn't give them back.

Just curious:
Do you listen to the net (0815, VHF68)
and
Do you come to the Monday night dinners?

[Taipe]

For algae scum, a medium-stiff nylon brush on an extension pole works quite well.

[zboss]

Originally Posted by Taipe

For algae scum, a medium-stiff nylon brush on an extension pole works quite well.

Sure and it takes the ablative right off with it.

[fstbttms]

Originally Posted by PamlicoTraveler

Are there any bottom paint experts that can opine on this? I did bottom paint last year and the boat has been in the water since. I can get a diver anytime to clean off the gunk and I am wondering myself when that is advisable. I don't want to scrape off the ablative paint.

So far I don't see barnacles - more or less just slime. What do the paint companies advise? At what point should I start to scrape?

The paint companies advise not letting the bottom become foul and removing any growth as soon as it appears. That is certainly not practical for most boaters. The bottom line is; clean the bottom frequently enough that even moderate growth does not occur and so that the gentlest cleaning media can always be used, thereby keeping the paint on the hull where it belongs. This frequency of cleaning will in large part be determined by the age of your anti fouling paint and the fouling conditions in which your boat lives.

[a64pilot]

Originally Posted by zboss

Sure and it takes the ablative right off with it.

It seems to me that about the time the algae ring around the waterline shows up, the paint is done, scrub away it’s not going to hurt anything.
I left for the Bahamas needing a bottom job, figured I’d just clean it way more often, water is clear and warm, why not?
Well I learned that it seems that even with frequent cleanings that the stuff that is easily removed, stays gone, but the stuff that isn’t continues to spread, and pretty soon you have a bottom of fur that you just can’t remove.

[skipgundlach]

This is a long enough thread that I expect it's already been covered, but...

Ablative paint is designed to slough ough (smiley).

Ordinarily that's done by sailing through the water often enough to make that happen by force of water. But lots of us don't move very often.

My now-6-years-old Sherwin Williams is showing a fair amount of the next color down, but STILL easily scrapes after months in very fecund water.

In the Bahamas, we intentionally ground and use lots of weight and a hookah to brush the slime. Having a cloud of paint as you do it tells you that you're activating new paint. However, I've found that merely pulling (like a paint brush, rather than pushing like a spatula) a wide drywall taping knife quickly, relatively effortlessly (compared to the deck brush I wield) removes the slime. Held at a 45 or so degree angle, handle in the direction of travel, the blade shapes to the hull's slight roundness.

The last dive here in Vero had the bottom of the keel VERY fouled; I presume I wore off all the paint early on with my intentional groundings, as we've never grounded other than one brief (no stop, mere bump) touch as we took a short cut north of Manjack in the Bahamas...

PS Windcall, you missed a nice evening out with fellow cruisers last night (smiley)