Peggie Hall wrote:
Glenn (s/v Seawing) wrote:
Did I read that correctly...urine will destroy an aluminum holding tank?

Yep. It'll destroy ANY metal holding tank, even 316 stainless.

Bummer...my Father just had one made for his trawler. Any way to
prevent this?

Nope. But it's not gonna suddenly disintegrate. The average lifespan of
any metal waste tank is about 10 years. Typically, it'll start to leak
at a weld in seam or fitting within about 2 years...and turn into a
colander in about 10 years.

So you might want to tell him not to panic...it'll be ok for the next
few years. Just keep an eye--and his nose--on it. And tell him not to
bother repairing the first leak...'cuz the first one is always ONLY the
FIRST one. The time to replace it with a good quality thick walled
plastic tank is after it springs te first leak. Till then, he can relax.

Any chance coating the inside with an epoxy coating will help extend
the lifespan? In commercial ships black water tanks ARE often built
into the hull of the ship as integral steel tanks.

Though I'm not fond of the practice myself, sometimes the tanks are
2000 - 3000L and plastic tanks of that size are a bit bulky to fit
into an engine room...

Evan Gatehouse