Under Water Hull Scrub

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Z

Zoey

If sailboats already have antifoul paint (Baltoplate) why do owners they have the undersides scrubbed? I thought antifoul is used to stop the growth?

Thanks
 
Sep 21, 2006
280
-Hunter 35.5 Washington, NC
Quick answer is antifouling paint impedes but does not stop underwater growth.
 
Jun 7, 2007
875
Pearson- 323- Mobile,Al
Slime!!! The antifoul prevents hard growth such as barnacles and oysters but you can get a layer of slime that slows the boat. This slime usually comes off with a soft sponge. I have always had trouble with barnacles growing on my prop shaft and propeller. A few barnacles will really ruin performance while motoring. I am talking about ablative paint. Hard paint will start growing hard stuff as the biocide leaches out. I guess the ideal bottom paint would be hard paint next to the fiberglass of one color and then a different color of ablative. That way when you see the hard paint you know it is time for another bottom job. I plan to do a bottom job in a few weeks. Hopefully all that will be required is a pressure wash light scrub and then rolling on the new paint. My last boat I took down to gell coat and it was a lot of work.
 

Tim R.

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May 27, 2004
3,626
Caliber 40 Long Range Cruiser Portland, Maine
Use ablative as a signal coat. That way when the top layer wears off to reveal the bottom layer, it will still be effective in stopping growth. Hard paint will not.

I stripped, applied Interlux barrier, a coat of red ablative and then 2 coats of white ablative. When the white wears off, the red continue to protect the bottom. At the end of the season when I pressure wash I can see where it needs to be touched up. In the spring I cover all the red spots and then recoat with 1 or 2 coats of the white.

You can also get silty dirt on your bottom like we do in Portland Harbor. Bottom paint does absolutely nothing to prevent it. There is even a decent current but silt from the moths of 2 rivers come together and sticks to the bottoms of all the boats.
 
Dec 19, 2006
5,821
Hunter 36 Punta Gorda
Good bottom paint

I did a bottom paint job on my 36 last Jan. after sailing her down from NY to Florida and than over to my new home port in Punta Gorda.
Any way she stayed in the water while I went to NY for July and august and came back to very hot no real wind in Sept so in Oct I dove on the boat to check the prop and it was badly loaded with barnacles and my folding prop did not open well at all.
I came back another day and dove under her with scraper and now she looks like new,dove again out sailing yesterday in cleaner water and checked the hull,
I was shocked at how clean the hull was with no slime,I will keep a eye when it needs painting again here in Florida.
Nick
 
Mar 2, 2008
406
Cal 25 mk II T-Bird Marina, West Vancouver
I think we must be lucky up here. Even though not many go sailing during the wet winter months, almost everyone keeps their boats in the water year round. My marina is located in a very sheltered cove that has a small creek running into it. Most boat owners use the marina travel-lift for a quick bottom power wash and inspect once a year and a full service lift to add one coat of Micron CSC ablative bottom paint about every second year. I have them do a wet sanding job to remove the accumulated bottom paint about every six years. Our water temperature ranges between about 4 to 15 deg C (40 to 60 deg F) year round. I’ve never had any barnacles or other hard growth in thirteen years of having my sailboat here. There are about 700 boats on floating finger slips (16 foot tide range) and there is no diving service available, as it is not needed. Yes, I do get a bit of slime / hair growth on the sunny side but it is only at the water line and comes off very easily with a deck brush. I think the normal bottom paint frequency for boats in full saltwater marinas around here is every year.
 

higgs

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Aug 24, 2005
3,708
Nassau 34 Olcott, NY
The problem with diving in and cleaning your boat is that swimming in a marina can get one electrocuted. All it takes is one shore powered boat with a wiring problem.
 
Jan 22, 2008
250
Cherubini 37c HULL#37 Alameda
Or your boat could explode and they find pieces of bloody wetsuit and scrub brush in the next county over.
 
Jun 7, 2007
875
Pearson- 323- Mobile,Al
I wonder if you dropped and anchor near where you are diving would that ground any stray currents and provide a safer dive??? Stray currents want to go to ground. The stray currents ""usually"" are not a problem in ocean water as the water provides an easy path to ground. The worst place is brackish water where the electrical currents follow the path of least resistence which is salt dependent. If you drop an anchor chain it should provide a good path to ground in the immediate area. I guess that if you had wire cables holding the dock in place it would provide the same protection. Any electrical people out there??http://boatingsailing.suite101.com/article.cfm/electric_shock_drowning
 
Jan 3, 2009
821
Marine Trader 34 Where Ever I am
The problem with diving in and cleaning your boat is that swimming in a marina can get one electrocuted. All it takes is one shore powered boat with a wiring problem.
This of course is a possibility, but every marina we have ever lived in has had ownersall over the marina that used divers to clean their bottoms, many times on a monthly basis. We have never heard of a diver being electrocuted or even getting a shock. Check with your neighbors. Chuck
 
Dec 19, 2006
5,821
Hunter 36 Punta Gorda
Marina

They must make sure the the electric and every thing else is top notch in Burnt Store Marina my home port.
I do watch plenty of divers clean boats in my marina every week,one of the divers has his golf cart parked next to the pool with all of his diving equipment
so it must be safe and I recently dove my boat to clean the prop with the shore power turned off and my zincs look like new still,I will be doing more diving under my boat out in the harbor and marina,my marina keeps a good watch on every thing,it's tops in my book.
Nick
 
Dec 19, 2006
5,821
Hunter 36 Punta Gorda
Jalepeno

I was just up to Vancouver in August and Victoria Island,you have a great sailing area,your area of sailing is fantastic.
Nick
 

zeehag

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Mar 26, 2009
3,198
1976 formosa 41 yankee clipper santa barbara. ca.(not there)
i have never since 1990 when i first moved aboard heard of anyone being electrocuted from diving under a boat in a marina...i read that and about choked my lunch.....from laughing--sorry--but the idea is preposterous....unless ye dives with a cord plugged into yer foot or a hairdryer or some such....bottom paint prevents much of the growth and folks have their boats dived so they can keep the slime off the bottom and the shellfish from growing despite paint----i think the diving is part of the problem but then......oi also believe in the 250 dollar/gallon paint--petit trinidad sr----it keeps stuff off the bottom of the boat and doesnt requirew diving --sailing the boat gets rid of the slime and cleans the bottom--i have seen friends boats with this .....worked great for 3 yrs ......wow....impressed me......and i am not easily impressed.....
 
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Mar 2, 2008
406
Cal 25 mk II T-Bird Marina, West Vancouver
seadaddler

Thanks we do have one of the best sailing areas anywhere in the world even if it is not as hot as down south and it rains a bit in the winter. We do NOT normally get snow at sea level only on the ski hills in the winter. On our "lower mainland" and the east coast of Vancouver Island, you can golf, sail and snow ski all in the same day almost year round if you want to spend the money for helicopter sking in the summer. By the way it is named Vancouver Island. Victoria is our capital city located on the south end of Vancouver Island.
 
Dec 19, 2006
5,821
Hunter 36 Punta Gorda
Very nice

We did two weeks in Alaska one land one cruise and ended in Vancouver where we used our time share to stay three days with a ferry ride onto the Island,we went to Stanley park,Grandville Island,Butchart Gardens was fantastic.
We would love to go back again some day.
Nick
 

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Feb 26, 2004
23,004
Catalina 34 224 Maple Bay, BC, Canada
Swimming

higgs posted this recently: http://forums.catalina.sailboatowners.com/showthread.php?t=112846

Someone asked for an electrician. I suggest you read Calder's Boatowners Manual for Mechanical and Electrical Systems about this issue. It's long, about two pages, and he does a very good description of the problems caused by BOTH marina wiring and your neighbor's boat's poor wiring, and a simple check you can make with a multimeter before you dive on in!
 

zeehag

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Mar 26, 2009
3,198
1976 formosa 41 yankee clipper santa barbara. ca.(not there)
higgs posted this recently: http://forums.catalina.sailboatowners.com/showthread.php?t=112846

Someone asked for an electrician. I suggest you read Calder's Boatowners Manual for Mechanical and Electrical Systems about this issue. It's long, about two pages, and he does a very good description of the problems caused by BOTH marina wiring and your neighbor's boat's poor wiring, and a simple check you can make with a multimeter before you dive on in!
electrocution and electrolysis are two different things....electrolysis is the fact of life known as having your prop[ and shaft and all else below waterline turn pink then to powder when you fail to keep your zincs maintained due to the electrical restructuring of the metal molecules and attrition of metals due to the electricity (ambient) in salt water when your electrical cord is dangled in the water or you are in a marina with poorly maintaained electrical systems....electrocution is entirely different......affects people not boats-----make sure the words you wish to use are the correct ones.
 
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