Bottom scrubbing

Figment · Post by **Figment** » Mon Jul 02, 2007 10:08 am

We discussed various bottom paint types and the need for the occasional scrub here at the tail end of my topside paint thread. This season I'm docked in entirely different water, and it's been an education.

My paint is still the Pettit Copper Bronze ablative antifouling (not to be confused with the Old Salem hardcoat), but I'm now in full saltwater instead of the 40/60 brackish water of the upper Branford river. This saltwater river is also much more clean than the silty murk of the old river.

The boat was launched mid-april, and the bottom was untouched until our grounding at the end of May. Diving on the bottom to inspect grounding damage, I took the opportunity to scrub away the light coat of brown algae that had developed since launch. "Scrub" really isn't the appropriate verb, "wipe away with a brush" is more accurate.
As the grounding took the antifouling (and a bit of barrier coat as well) off the bottom edge of the keel, I've been cleaning the bottom every other week since, thinking that I might be able to stay ahead of any hard growth until the customary midseason quick-haul.

What I'm learning, I think, is that light has more to do with bottom growth than salinity or anything else.
The bottom of the keel, with no antifouling protection at all, has been almost completely clean.
The hull surface down to the tuck of the keel has seen the most growth.
The south-facing port side has had a good heavy coat of growth, far more than the starboard, which is also "shadowed" by the dock finger.

Now, onto the tools.
Fins. How on earth did I ever do this without a set of swim fins? Madness!
The brush. I've been using a soft-ish deck brush with a 2' wooden handle. The mild positive bouyancy is helpful for keeping the appropriate pressure on the underside of the hull.
Though the brush is rather soft-bristled, I'm concerned that these more frequent cleaning sessions will work through the paint before the season ends, and I'm thinking about switching to a carpet scrap.
I'd love to hear thoughts on an effective handle arrangement for this. Anyone?

Post by **dasein668** » Mon Jul 02, 2007 10:47 am

Figment wrote:...until the customary midseason quick-haul.

You haul mid-season??? Mike, you're only in the water for 5 or 6 months, aren't you? What on earth do you need to haul for? And you call me nuts? Hello, Pot! hehe

Figment wrote:...I'm thinking about switching to a carpet scrap.
I'd love to hear thoughts on an effective handle arrangement for this.

How about a Swiffer. A little velcro on the swiffer pad and the back of your carpet scrap... Nicely articulated head. Should work great, I would think.

Figment · Post by **Figment** » Mon Jul 02, 2007 4:02 pm

Ideally it's more like 8-1/2 months, but yes I am indeed the pot!

Yeah, maybe "customary" was the wrong word. Not everyone does it, just those who moor in full-saltwater, and who plan on using the boat past Columbus Day. Just a "short haul": up in the slings, quick-clean the bottom, check prop and zincs, and back in the drink. If any portion of the bottom actually dries, you're taking way too long.
I'm sure Hirlonde and others here can shed light on S.O.P. at their yards.

As I'll need to apply some paint this time, I'll need to actually get blocked-up overnight.

Post by **dasein668** » Mon Jul 02, 2007 4:09 pm

Geez, we only hauled Palawan every 12 to 18 months. Tom would dive on her once or twice during that time. I'm surprised to find the fouling to be that much worse down in CT.

Anyway... interesting!

Figment · Post by **Figment** » Mon Jul 02, 2007 4:19 pm

Oh I probably should also have noted that if you scrub every so often, the midseason haul is almost certainly unnecessary. Like any other maintenance task, the more often it's done, the less arduous each individual occasion is. Everyone strikes their own balance.

Fouling gets worse in warmer water (as I understand it), but not THAT much worse! =D

CharlieJ · Post by **CharlieJ** » Mon Jul 02, 2007 6:54 pm

interesting thread.

I've had Tehani in the water for two years now, down here in Texas waters. We scrubbed the bottom last year while in Florida- dove on it with scrubbers. Took two of us about 30 minutes.

I scrubbed a few weeks ago but nothing much other than some slime. We do have a few barnacles where bottom paint has been scraped off, such as on the bottom of the keel and some right around the very top of the rudder. Other than that she's pretty clean. We'll be hauling for a bottom job sometime this summer though cause it's getting to the point where it needs a few new coats..

Just for information the bottom paint I use is ACP 60 from Pettit, in black.

Post by **Tim** » Mon Jul 02, 2007 7:17 pm

The racers scrub regularly, of course, but cruisers don't bother around here, at least not as a general rule. Even the racers rarely haul for that purpose, choosing to hire divers on a regular basis instead.

In the short season and cold water, growth is limited to light-to-moderate algae. With no scrubbing during a 5-month season, this is as bad as it gets (see photo).

(Paint: Micron CSC Ablative, one fresh coat applied each spring)

Note that most of the growth occurs during September, when the water's warmest. Things stay remarkably clean till then.

Sometimes I think that the more you scrub, the faster the stuff grows.

CharlieJ · Post by **CharlieJ** » Mon Jul 02, 2007 8:10 pm

besides- the very best way to scrub a bottom is with water- SAILING!!

Sail it often enough and you won't get as much stuff on it. Grin

Post by **dasein668** » Mon Jul 02, 2007 8:22 pm

Gee Mike, you're kind of taking a ribbing here! 's'ok. We still love ya, man!

;-P

Figment · Post by **Figment** » Mon Jul 02, 2007 9:05 pm

I'm realizing how very loose terms like "scrub" "clean" and "growth" are!

I just scrubbed (wiped away slime) yesterday, and in a week's time my bottom will look like Tim's pic above. This isn't the end of the world, of course. It's just slime, not "hard growth".

Actually, now that another boat has taken the slip next to mine (south side), perhaps the growth will slow down a bit.

Post by **dasein668** » Mon Jul 02, 2007 9:13 pm

Now that we've all beat on Mike for a while...

Did anyone else have any better ideas than a Swiffer for Mike's carpet-scrap-scrubbie?

JetStream · Post by **JetStream** » Tue Jul 03, 2007 12:20 am

Sometimes when we have to scrub the light growth during the season or for a race, we use cheap cotton gloves. It's pretty fast and they don't take all your ablative paint off.

Hirilondë · Post by **Hirilondë** » Tue Jul 03, 2007 5:42 pm

I'm at the opposite end of L.I. Sound from Mike and my boat is in the water for 6 months. I use Micron Extra ablative. I paint the top foot of the bottom, the leading edge and bottom of the keel and the rudder, then a complete coat on the entire under water each year. I wipe the slime line (the top few inches in the water) off once a month from my dinghy (if I happen to think of doing it) with a sponge and my depth transducer a couple times a season with a scrunge pad and/or my custom bronze scraper. When I haul in early November I find a thin slimy layer of growth which comes off with the power washer even with the tip a foot away.

New York City must be dumping something in the Sound that is speeding up the growth on Mike's boat!!