Water tank fun

[IDS]

Just embarked on some long overdue water tank maintenance, not done since I've owned the boat. Now I know why I've been putting this off for so long. My tanks form the sides of the well deck, so there are 2 of them, each 2 m long, one each side connected by a ballance pipe. So twice the agony.

After draining and opening the side mounted access panels, the inside looked frightening with large encrustations down the sides of the tanks, which look like it could be rust. Photo of access panels shows the sort of stuff.

My first thought was that it was lots of rust, but it yields to a scraper leaving a very pristine surface of the original plating, no obvious rust or pitting. The encrustations are very black, soft and crumbly beneath the crusty superficial rusty looking tint on the surface, I wonder if it is a degradation product of the previous coating, which I assume was some kind of bitumen. It has actually done a superb job of protecting the steel, even after many years (>9 ) of no tank maintenance.

My question is what does the forum recommend as a coating now, since I discovered today that the bitumen product stocked by Midland Chandlers is no longer WRAS approved for potable tanks. I was checking the manufacturers (Everbuild BlackJack) Tech data sheet for coverage, and there they state there that it is 'not suitable for potable water tanks', On the tin it used to say it was.

Edit to add: Everbuild confirm the product is no longer certified and should not be used for potable tanks.

Edited September 10, 2015 by IDS

[Neil Smith]

If it has been used for years without killing anyone then I would not worry as it must be better than the crud you have now, if not there are other products available that are approved just google for wras approved water tank coatings.

 

Neil

[nb Innisfree]

I once asked someone from International why their Intertuf blacking was no longer certified as potable and he said they had given up the certification because their product wasn't being allowed to dry properly after application so was failing. He obviously couldn't recommend it for potable use any more for legal reasons but confirmed it was still the same product.

[Bee]

Yeugh, Not having a cup of tea on your boat. Agree with Neil, google potable water tank coatings, whatever you use must be better than that.