Petrol in Hull space

[brucehawsker]

My Solent has started to produce some petrol contamination in the void space in the hull. Noticableonly when I remove the bung from that void to the bilge when she is back on shore. Water has always built up in that void, especially after a rough trip, but it is getting murkier brown and the petrol smell in noticable when I open the bung to let her drain.

Particularly bad after going to Chichester where the fuel attendant inisited in filling her up himself and got a strong blowback out of the fuel filler as he was over enthusiastic.

How do I cure this?

Any ideas?

Is it

tank leak
pipe leak
leak from the vent

none of these and just a feature of ribs.....

Thanks

Bruce

[Pete7]

Originally Posted by brucehawsker

none of these and just a feature of ribs..... Thanks
Bruce

certainly not and potentialy quite dangerous. First check should be the fuel and breather pipe jubilee clips to ensure they are tight and that there are two clips on each connection.

Pete

[jwalker]

Bruce, if you suspect the petrol got into the space after the blowback, there must be a leak in the area of the filler. You shouldn't get water under the deck either. If you can locate it, you may fix two problems with one repair.

I don't wish to worry you unnecesarily but if you've been regularly getting water under the deck and your tank is stainless steel, you could be in for a big repair. Stainless steel is only stainless because of a surface layer of chromium oxide. If there are parts of the tank where water can permanently lie in contact with the metal, the oxygen in the water will deplete and the steel will begin to rust. This can happen rapidly.

[Downhilldai]

Firstly, I'd check the fuel take-off hose. This may be fractured or chaffed?
If ok, try checking the void when the boat has been ashore for a few days with a full tank of fuel. If there's leaked fuel present, it's likely to be a failure of the tank, as the sender unit, breather and fill hoses should be above the fuel level.
If no leaks, your problem is elsewhere. Sometimes the flange for the fuel gauge sender (if fitted) is prone to leaking. This would be the next place I'd go looking. After this, check the fill and breather hoses. A method I've used in the past is to plug the take-off hose and lightly pump some pressure into the tank through the breather hose, using a bicycle pump, toob pump, or similar. You should be able to hear any escaping air when the tank is under moderately light pressure.
If none of the above identifies the source of the leak, someone's pouring fuel in your bilge when you're not looking.
Good luck.

[Cypman]

Gently pumping up the tank is a great way to test for leaks, use a solution of washing-up liquid and water and sponge liberally around all joints, jubilee clips etc and you will soon see if you have the problem. I also recommend this test before installing a new tank, it saves heartache afterwards and puts one's mind at rest regarding possible fuel leaks.