Quincy Shipyard barge cracking failure

Aluminum-cleaning rinse tank maintenance failure. Rinse water pH had drifted to 2.3 (Coca-Cola acidity). Used as cautionary example that chemical-bath cleaning requires maintenance discipline. Barges were destined to carry number six bunker oil.

Now the problem with cleaning tanks is maintaining them. I had a problem down at Quincy Shipyard, probably the late 1970s, maybe early 80s. They were making some barges that were going to carry number six bunker oil. The rinse tank had a pH of 2.3 — the rinse water had a pH of 2.3. That's as strong as Coca-Cola in terms of acidity. And so they had cracking problems.

Brass heating pipes (3" dia, Dowtherm-heated) inside heavy-crude barges; stress corrosion cracking traced to rinse-water pH of 2.3. Recommendation: change rinse water weekly or daily, with pH monitoring.

You have to actually change your deionized water sometimes. You're in the Coast Guard, right? You have to qualify ships. One of my first consulting jobs, when Quincy Shipyard was still in operation — I got a call because they were building some barges to transport a very heavy crude oil. They had to put some heating pipes in there so they could heat it up to pump it back out of the barge. They can pump it into the barge when it was warm — maybe it's number six fuel oil. Number six fuel oil, if you just let it come to room temperature, doesn't flow too well and doesn't pump very well. So they made these brass pipes like three-inch diameter and ran them through the inside of the barge, and you could run Dowtherm, which is a mineral oil type of heat transfer fluid.