Inky black bilge?

[jim lee]

Every now and then the bilge water in my boat goes inky black. It stains everything black in there and its a nightmare to clean out. Anyone else seen something like this? I thought it was something to do with corrosion and shore power, but this year I've not plugged in shore power since.. March?

Maybe its some biological deal when the first rains dribble in there? (Seems to happen after a rain)

Eveything seems fine for months then all of a sudden poof! The dreaded black bilge.

Any hints? I'm completely confused here.

Thanks!

-jim lee

[Charlie]

Hi Jim:

Sounds curious. Do you store any octapuses on board? Maybe they got in a fight. When you clean it up what do you use? That might lead to an answer. If its biological than chlorine should kill and clean it. If its oil detergent would help. Could it be dirt or something coming down your mast with a rain? Do you notice it starting in any particuilar area first? You might try the washable marker trick -- draw a line with a washable marker around the area of the bilge and then that will aloow you to see wher it is comming from b/c the marker will have washed away.

[senormechanico]

A very small amount of diesel crankcase oil will make a very black mess even if it's very thin. Any water below will still be quite clean.

Steve B.

[Kai Nui]

Is it oily, or slimey? An occasional oil leak is a likely culprit, but if it is slimey it could be mold. It is possible that you have mold on the inside of the hull that is being washed down by leaks under the chain plates or stanchions when it rains. Try removing some hull coverings. If the hull is not covered, I would look for an area of the bilge that is not properly draining. It is possible that there is oil residue accumulated in an area of the bilge that is plugged up, and only releases a bit of water when the boat hits the right angle. If that doesn't work, well... That's all I can come up with

[jim lee]

Its not oily. Not slimy.. I've never seen it "start". Just now and then I look in the bilge and zowy! Black bilge ink!

-jim lee

[delmarrey]

Do you have any cast iron parts the get submerged??? Cast iron turns black in acidic water (stagnet (sp) fresh water). Like sewer pipes........._/)

[Jon D]

Could also be mold. Add a little bit of bleach to the bilge and see if the black goes away....

[LaLeLu]

It may be coming from your stuffing box or shaft seal. How long has it been since your cutluss was changed? Last year we had a strut failure while we were under power and the force from the strut breaking caused ink black water to spray out of the stuffing box all over the bilge. At first we thought it was oil - turned out not to be. We didn't know / wouldn't have known that black stuff was in there had the strut not broken and caused abnormal force on the shaft. I am thinking that if you have a cutless that is going out, some of the black crap might be leaking out of the stuffing box / shaft seal. Just a guess.

[Richhh]

Probably an 'aspergilus' infection ... a species of 'nasty' molds/mildews.
Put some ammonia or other caustic into the bilge and see if this doesnt 'clear' the infection.

If that doesnt clear it then its probably a bacterial infection thats using the accumulated bilge oil as a nutrient source ... needs killing with a heavy dose of bleach, then 'several' mechanical scrubbings with caustic detergent, etc. to loosen the 'biofilm' thats adhering to the walls, etc. CAUTION: DONT MIX BLEACH AND CAUSTICS .... DO THESE STEPS SEPARATELY WITH **LOTS** OF RINSING IN BETWEEN.

[Leighton]

I have a similar problem with green water in the bilge. I suspect its copper oxide, which is a bit worrying and I try and not think about to much!!

Leighton

[Alan Wheeler]

Leighton, I doubt it is Copper Oxide. That's Blue anyway.
What colour is your Engine cooling water additive. You may have a cooling leak or most likely, overflow when hot.
Jim, depending on what this actually looks like, I doubt this is any of the above. Includign Cast iron, It is true that cast iron goes black, but it is the cast itself, not the water. Can you describe the water in greater detail. Can you take a sample in a clear glass container and hold it up to the light and describe the look. Is it particles of black stuf suspended, is it just inkblack, does it float on top and so on.
I suspect it could be soot from an exhaust leak somewhere along the exhaust hose and the mixture is running down into the bilge.

[LaLeLu]

You don't believe me that black ink water lives in your shaft log and can come out the stuffing box? This picture below shows remnants (black dots on the right side of the hand) of the "ink" that shot out of our stuffing box - and coated the bilge.

[Kai Nui]

Not oily, not slimey, it is likely not oil or mold. A dose of bleach couldn't hurt. With all of this in mind, I am leaning towards Wheels' suggestion of an exhaust leak. I would also check you holding tank. Especially the vent line. Which brings me to the next question, is there any odor?