Traces of diesel in the bilge

[SaltyMetals]

Once you hv found & fixed the leak there is a prevention you can use. Certainly available in Europe and i am sure in the US. It is a diesel additive which combines with the water in the bottom of the tank and then goes into solution in the diesel. This all gets consumed by the engine with no harmful effects (as far as I know) with zero pickup/blocking of yr filters. A very standard diesel treatment in cold climates where you get condensation in the tank in the winter and most often used in cars. Best to leave the tank full when you are away to minimise the air-gap where the condensation would occur. There is another school of thought about putting a moisture filter in the diesel breather but frankly IMHO when you do the maths this is minor compared to the heating and cooling of the air-space above the diesel in yr tank which causes the condensation since the breather is often quite long so no new (moist) air would be sucked in as far as the tank. (On my boat the breather goes from centre of the boat all the way to the stern (5m/16ft) .There is another thread somewhere in CF that discusses this whole subject.

The other thing i discovered was the auto bilge pump that i have has two electrodes which will activate the pump if they get covered in water. I could not figure out why the pump would never empty the bilge until i realised that it had pumped out all the water but the diesel did not make the conductive contact to keep the pump going. Eventually pumped out the diesel manually (at sea) and mopped up the rest w diapers.
Andrew

[Rick Williams]

We had this problem on a 25 year old Bayfield. The bottom of the tank was occasionally in salt water so it had developed pinholes but it was never obvious as I kept he tank full and (here's the funny part) diesel is lighter than salt water so as long as the tank was full the bilge water did not come in. When the weight of the fuel became less when we were on a long trip, the bilge water would leak into the tank and would get picked up and the engine would die. We didn't know the bottom of the tank was like swiss cheese until the middle of a long passage when the tank was very low.
Diesel has a very high flash point so your bilge isn't going to explode unless it gets very hot with a lot of pressure but oil absorbent sheets and balls will get most of it without retaining water.

[Cheechako]

The tanks often get a leak on the bottom quite often if in the bilge, even up high in the bilge. I have had... at least two boats with that issue. One was only 7 years old. It occurs from dampness between the tank and any supports it rests on. It's very high on my list of things to check when buying.
-Hard to confirm, but if you make the bilge sparkely clean and dry, then let it sit and test the bilge near the tank with dry Toilet Paper after a few hours, you will see if it's oozing down a glass structure or etc.
-If it doesn't get in the bilge when you are sitting at the dock, it's likely not the tank. Check where the return line goes to the tank, or any wet fittings on/near the engine etc.
-As far as gunk goes, old boats accumulate stuff in the tank. It will clog your engine at the worst possible time. Get your fuel "polished".
If your tank is bad you can either pull it and get it repaired or one made, or you can cut the top off and put a plastic tank inside the old tank.

[Curtinjulianna]

Hey guys!! So update, I was cleaning out the cabinet in the bathroom that is right beneath the fuel tank, and I noticed fuel on the floor of the cabinet and a huge wet spot down the side. Hmmm starting to think more and more it might be the old tank. However, I think there could also be some issues with the hoses and what not. We are going up 8 hours tomorrow to civilization and going to get some help looking everything over. Will update with the news on Friday! We are going to pump our bilge before leaving and dispose of the diesel in a diesel safe bin. I got some of the pads so hopefully those help! Any other safety things I should consider with a leak like this? Thanks!!!

[Cheechako]

Originally Posted by Curtinjulianna

Hey guys!! So update, I was cleaning out the cabinet in the bathroom that is right beneath the fuel tank, and I noticed fuel on the floor of the cabinet and a huge wet spot down the side. Hmmm starting to think more and more it might be the old tank. However, I think there could also be some issues with the hoses and what not. We are going up 8 hours tomorrow to civilization and going to get some help looking everything over. Will update with the news on Friday! We are going to pump our bilge before leaving and dispose of the diesel in a diesel safe bin. I got some of the pads so hopefully those help! Any other safety things I should consider with a leak like this? Thanks!!!

Nah, other than a headache from diesel smell maybe!

[Dougtiff]

As already mentioned, you can end up in a lot of trouble if your caught dumping diesel in the water, no matter why or how little, i would pump the tank dry,ie, into some jerry can's, then tap off of them, via a 12 volt fuel pump, my own experience was that you can end up being charged THOUSAND'S of Dinero by Home land security [Coast Guard] for the smallest amount of discharge,[if you don't have insurance covering a spill, it can cost you THOUSAND'S], so be smart, don't just blow it off, and i must say, that seems to be your mind set at the moment.

[Boatyarddog]

Originally Posted by Cheechako

Nah, other than a headache from diesel smell maybe!

Had that same smell in my boat.
Just a small leak ,but pervasive enough to give you a headache.
Luckly, I could pull the tank, while the effort was difficult, it paid off.
A new bottom was required due to pin hole rot. Seen in the corner of the tank.
Work was performed by Zieglers Welding in Olympia Wa.,At a cost of $150.00
No problems now.
Cheers,
SV Cloud Duster

[Boatyarddog]

Originally Posted by Dougtiff

As already mentioned, you can end up in a lot of trouble if your caught dumping diesel in the water, no matter why or how little, i would pump the tank dry,ie, into some jerry can's, then tap off of them, via a 12 volt fuel pump, my own experience was that you can end up being charged THOUSAND'S of Dinero by Home land security [Coast Guard] for the smallest amount of discharge,[if you don't have insurance covering a spill, it can cost you THOUSAND'S], so be smart, don't just blow it off, and i must say, that seems to be your mind set at the moment.

As diesel fuel evaporates, it's less harmful to the environment.
However, a sheen is obviously noticeable.
Tighten your packing a bit and turn off the pump.
Add bilge ABSORBANT pads, you DO have these on your vessel, right.
They absorb diesel not water.
Then to a plastic covered pail or bag, to be off loaded.
Surround the tank bottom with them if you think it's the tank.
Place around the engine to locate an active leak on the engine.
You'll find the leak if you look hard enough.
Good Luck!
SV Cloud Duster

[S/V Serenity]

In our case (and granted our leak was not as large as your appears to be) the leak was from the copper tubing intake line from one of our diesel tanks. These tend to get work hardened, with age. Switched all the copper tubing to USCG approved fuel line and that solved the issue.
It was hard to find the leak, since the copper tubing ran through pretty inaccessible areas.

[Ken Pole]

Assuming that pinhole leaks are the source, a new tank (I recommend one of the polyethylene units) shouldn't cost more than $350-400. I replaced mine last summer. It took about three days for it to be delivered in Canada but once in hand, it took less than four hours from siphoning the old tank to restarting the engine as well as replacing fuel lines, etc., to complete the installation. However, that was with fairly ready access through a cockpit locker. It also was a preemptive decision in that I did not have leaks but knew that my metal tank dated to mid-1970s. Mine was manufactured by Tennessee-based Moeller Marine, which has a good reputation in the industry, but I'm sure there are other manufacturers.

[sailores35]

Get in touch with George McCreary at Caliber Yachts.

[gonesail]

Originally Posted by Curtinjulianna

I noticed fuel on the floor of the cabinet and a huge wet spot down the side.

if the tank is on the other side of that cabinet then you know you need a new one. Caliber was known to foam the tanks in place which makes it a bit trickier to remove. In my case the old tank had to be cut into pieces. I found the plastic tanks did not fit as well as the custom aluminum and had one made

[Mjames]

I had diesel in my bilge last season. it came from me filling the tank all the way (diesel was up the throat of the tank fill) which we presume caused the gasket around the tank access port to fail. Re seated the gasket and am careful to not fill too far and no further problems. Hope you find the issue...meanwhile definitely agree about using those petrol absorbing pads.

[parkstone bay]

I replaced a steel 15 imp gallon/60 litre tank winter of 2017/18 with a plastic 30 litre one. Getting the old one out was a nightmare, but, of course, putting the new one in its place was a doddle. Connected everything up, bled the system, absolutely marvellous! Came back after a 2 weeks break, 15 litres of diesel in the bilge. One of the compression fittings wasn't quite nipped up enough - no obvious leaks/weep, but just enough to siphon fuel out until the level dropped to where the leak was. That was a real bummer!

[smacksman]

My 1985 Lehman diesel had rotted fuel lines that weeped. I was told that modern bio-diesel was bad for the rubber used in old fuel lines. Whatever, I got a hose shop to braze on new hollow bolt fittings to the old metric banjos with new hose all round for $150. Problem solved