Water and oil

[alanocean]

Here's a problem we had a bout 4 years ago....... On watch one day the oiler on watch came to me a said there was oil skim in his mop bucket that has never been there before. We figured that he must have mop a bit of oil that was unnoticed. The next day he cleaned his bucket and filled it and sure enough there was oil in his bucket. Checked a few more taps in E/R and also oil in the water. Any idea's how the oil got into the fresh water system?! And sabotage was not the ansewer

[D Winsor]

There are a couple of possible causes for this.
Grease forced into the water system caused by over aggressive greasing of the domestic water pump packing glands.
Oil or grease coming from pump bearings

[alanocean]

Right as far as possible causes but not this one.. A hint would be something you wouldn't do but something someone might.

[Big Pete]

An interesting problem, but it sounds like something no one would guess. It sounds like operator error rather than a structural problem. Maybe someone dumping waste oil down the wrong sounding pipe?

BP

[alanocean]

True that is would be hard to guess so here it is... When finish pumping slops ashore the chief wanted to blow through the line but there was no fitting after the discharge valve so he put his air line to the pump casing and blew it through with the suction shut. There was a small solinoid with fresh water for priming ( Sea water now and non re-turns installed) and he blew approx 5 gallons of sludge waste into the domestic system. The oil went through most fresh water lines on the ship but most being returned to the domestic tank. The tank was drained down and opened for inspection.... What a mess!!! Wish I had a few pics . This is only 1 example of stuff this guy did there are many more!

[JK]

I had been mulling this over and not getting anywhere with it. I figured it was something to do with a funky setup somewhere in the engineroom.

We had an engineer pump slops into the sump of a running DA, through the sump drain valve. That was an expensive little mishap. Still not quite sure how it was done.

[The Dieselduck]

That always makes me nervous to see cross connections from various systems into the fresh water system. I always thought the US Public Health inspections on cruise ships were just BS, but they did have very good design specs that prevented this from happening. I look on my current boat and cringe every time I see solid connection into the potable system, from the header tanks, priming circuits - like the aforementioned problem, to the solid connection to the ows, all possible sources of cross contamination to the pot system. Even worst right now, is the 40 year old vessel's fresh water tanks have no cofferdams between fuel tanks and pot tanks, and to boot, the pipework (old and raggedy looking) goes through the fuel tank. Luckily we are close to ports and always have plenty access to bottled water. Now we just have to worry about PBA, for the moment.

[JK]

You mean Non-potable water tanks, eh Martin? Surprising that they have gotten away with that situation.

I dealt with a ship that has a cross-connect between the sanitary water and potable water system.
They remembered what the valve was for, after it was opened and contaminated the entire potable water system with harbour water (eeewww).

[The Dieselduck]

Health and potable water systems on board, I don't believe, are Transport Canada's strongest enforcement point.

[Big Pete]

Ashore in the UK domestic water regs require non return check valves to be fitted in supplies going to garden hoses and anything else where contaminated water could conceivable go back into the system if mains pressure was lost.

e.g. central heating boilers with a presurised expansion vessel rather than a gravity header tank are supposed to be fitted with 2 isolating valves and a detachable piece of pipe between the water main and the inlet to the heating system.

Often Marine practice lags well behind shore practice.

When I came to sea it was common practice to have 3 Megator pumps, mounted on a common skid, 1 for Fresh water, 1 for sea water (Sanitary use) and 1 in the middle there was a common standby punp that could be connected to either system.
Of course these should all have been fitted with an additional pump and the sany & FW systems permanently separated, since then, as the Regs changed.

BP

[JK]

Martin, it is obvious you never dealt with the Water Witch on the East coast!!