Water Babies

Olene Boyko of Urbanna, Virginia, asks:"On removing the inspection plates on the welded steel water tanks aboard my 48–foot boat, I could see they were painted on the inside with a blue high-gloss rubber-like paint. I also saw quite a bit of corrosion around the edges of the opening for the inspection plates and a considerable amount of scum and algae growth. Bleach has
Author:
Publish date:
Updated on

Olene Boyko of Urbanna, Virginia, asks:

"On removing the inspection plates on the welded steel water tanks aboard my 48–foot boat, I could see they were painted on the inside with a blue high-gloss rubber-like paint. I also saw quite a bit of corrosion around the edges of the opening for the inspection plates and a considerable amount of scum and algae growth. Bleach has taken care of the scum, but there doesn’t seem to be any way to strip off the paint and start over. I can brush and lightly grind the rusty spots, but I’m not sure what to do next. I would like to repaint the rusted areas with a water-potable paint and have looked at several paints with rust prevention characteristics, but I am concerned about their compatibility with drinking water. Unfortunately, no one seems to know what paint is inside the tanks and the builder can’t be reached for advice."

Don Casey replies:

Believing that an inert paint product would be able to prevent or retard algae growth was a bad idea right from the start. The usual way to fight algae is to add a small amount of chlorine to the water. If the painted surfaces have protected the interior metal from corrosion and the tanks still are intact after 18 years, except around the edges of the inspection plates, I would leave the paint undisturbed. My guess is that if the corrosion is limited to the area around the inspection ports, the probable culprit is acid in the silicone sealer that was used to seal them.

The standard tank coating today is a potable-water approved epoxy formulation. These epoxies are made by a number of manufacturers. An added benefit of epoxy is that compatibility with the blue coating, whatever it is, shouldn’t be a problem. When you use one of these epoxies, overlap the repair onto the original paint to create a good seal. No matter what epoxy coating you choose, follow the instructions carefully, particularly with respect to the primer you use on the bare steel. Also be sure you remove every bit of the silicone sealant before applying any new coating.

As for the inspection plates, if they let any light into the tank’s interior this will encourage algae growth. If the tanks and plates aren’t in a dark location, paint the exterior of the plates so they are opaque.

Finally, because you can’t identify the existing paint inside the tank, I think you should test the water for chemical content. Try to test water that has been in a tank for a period of time.

Related

TOTW_PromoSite

SAIL's Tip of the Week

Presented by Vetus-Maxwell. Got a tip? Send it to sailmail@sailmagazine.com The double range  Every skipper knows about ranging two objects in line to keep the boat on track in a cross-current. What’s less obvious is monitoring both sides of a gap such as a harbor entrance. ...read more

FamilyCruise

Bareboating on Puget Sound

Depending on where you are, Puget Sound can look no bigger than a mountainous version of the Intracoastal Waterway. That’s what I thought when I first laid eyes on it from the lighthouse at Mukilteo Park on a sunny day last July. Then I went to the top of the iconic Space Needle ...read more

Bali4point1

Boat Review: Bali 4.1

Coming fast on the heels of its predecessor, the Bali 4.0, the Bali 4.1 adds a number of improvements, many of them inspired by feedback from owners and charterers. She’s an evolution of a concept that has already proven popular and very many benefits from its builder’s ...read more

Headsail

Ask Sail: Silencing A Rattling Headsail

Q: Our Pearson 26 has a 110-percent jib that tends to rattle very noisily at the top hank. We only bought the old boat recently, but it must have been happening for a long time, since there’s a deep groove worn inside that bronze hank. The jib has an unusually large and wide ...read more

Alerion2048x

Alerion Yachts 33, the 90 Minute Get Away

Easy to sail, luxurious, and swift; the Alerion 33 is the solution to your busy life. The intuitive, simple rig design, easy set-up, and put-away mean there’s no need to wait for crew to enjoy a weekend, a day, or an hour out sailing. Her beauty and comfort are evident in the ...read more

anchor

Know how: Ground Tackle

Your ground tackle is like a relationship—the more you care for it, the longer it will last. So, how do you enhance the relationship? First up, think of the accommodations—a damp, salt-rich, often warm environment, just the kind of thing to encourage corrosion. What can be done? ...read more

DSC_7522

Boat Review: Beneteau Oceanis 46.1

The Beneteau sailboat line has long represented a kind of continuum, both in terms of the many models the company is offering at any given moment and over time. This does not, however, in any way diminish the quality of its individual boats. Just the opposite. Case in point: the ...read more