Bottom scrubbing issue

[SeaDogRun]

I bought a 1987 Catalina 27 last year. It is on a lake and stays in the water year-round. This weekend, I was going to scrub the bottom to get any growth off and prepare for the sailing season. I used a elongating pole and a scrub brush. While the brush worked fine on the rudder by getting off some brown growth, the first passes on the bottom brought up a black substance. It had no smell like the growth from the rudder. A picture is attached. I'm guessing this is anti-fouling paint? I can't get in touch with the old owner to confirm when the last bottom job was done but I believe it was at least several years ago. Anyone deal with a similar issue? Any advice? I stopped scrubbing after the first few passes.

 

[Capt Robbie]

looks like water mold and or algae growth , any more then four years without repainting, I think you are over due. After several years the paint doesn’t owe you anything. I’d haul, clean, and paint and call it a day for a few years.

 

[Parsons]

Lots of guessing will occur here, but this is mine -

1. What you see here is the slime that has accumulated over the years, and you have not gotten near bottom paint
2. The bottom was not painted recently (why pay $$$ when you're going to sell anyhow) and should be done
3. You are in very warm water (Corpus Christi), fresh or not, and stuff will grow wildly.

Suggest you haul and paint, if you want to sail. Ask around what types of paint work well in fresh water for Texas. VC17 (or the West Marine equivalent) are good for colder fresh water but may not be strong enough for your lake. If you intend to scrub yourself and not dive it, I suggest looking into a neat device called a "dry diver" which is rigged with a scrubby pad, pool floats, and a long curved pole. Yes, you could build it yourself from a picture, if you were crafty.

 

[jssailem]

I'm guessing this is anti-fouling paint?

That could be. Is it the same color as the paint you see just below the waterline?

More likely it is slime.

It is suggested up here to paint the bottom in layers of different color. If you use a primer paint it in say red. Then use your finish color - blue two coats over the top.

Now as the ablative or even your super smooth VC17 erodes you know you still have enough on the bottom for another season.

Paint that limits slime of critters from attaching to your bottom operates by leaching chemicals in the paint. The critters dislike the chemicals so they seek shelter some place else. When your paint ages there are fewer chemicals to leach and the critters return.

If your sitting your growing a lettuce patch.

Keep your boat moving... and repaint when you see the undercoat showing.

 

[Davidasailor26]

I also think it’s just slime. I haven’t seen paint come off in clumps like that. More often just as a power that discolors the brush (and water if there’s more). If the last bottom job was several years ago you’ll probably find the slime coming back pretty quickly.

 

[Joe]

It's going to be difficult to clean the bottom without diving so you can actually see the results. My choice would be to hire a local diver to give the bottom a thorough cleaning, perhaps taking a couple pictures... then... within a few days go ahead and haulout for the new bottom job while the surface is still fresh.

That's not paint on the brush, btw. The shape of the boat's bottom makes it impossible to reach some area with a straight handled device but even with a crooked one you really need to occasionally inspect it for a proper evaluation. Therefore, now's the time to get some eyes on it to help make the right decision.

 

[mikeracca]

If your sitting your growing a lettuce patch.
View attachment 203419
Keep your boat moving... and repaint when you see the undercoat showing.

Hey! Where did you find a pic of Luna out of the water! LOL

 

[jssailem]

I looked a long time and through many websites. Just got lucky.

 

[SeaDogRun]

Y'all are awesome! Thank you!