Diesel Tank Ullage Removal

Halo

Halo

Well-Known Member
Joined
10 Nov 2009
Messages
2,051
Location
Wetherby
Visit site
Dear All
Its getting round to haul out time and I am wondering what to do about getting the muck out of the bottom of my diesel tank.
My previous boat had a nice drain valve right at the bottom. The new modern boat has a flat bottomed plastic tank with no chance of fitting a sensible bottom drain. With a large quantity of diesel in the tank (to minimise condensation) I dont really want to drain into barrels - partly because I dont have any and partly because of further contamination and fuss.
Has anyone worked out a way to suck out the very bottom of the tank via the filler in a modern yacht ??
Many thanks in advance
Martin
 
andrewbroadbent said:
A vacuum type engine oil extractor has been recommended on here for sucking the crud out of the bottom of diesel tanks.
Click to expand...

Yep, I've done that.

I did need to open the inspection hatch, which was deliberately placed above the deepest part of the tank. Trying to hoover the bottom of the tank via the filler opening could get a bit gynaecological.

Pete
 
FWIW
Ullage is the amount by which a tank is less than full .... It is the space remaining above the fuel.
 
VicS,

Yes you are quite correct but I can recall (in a previous life when I ran the bar at the local yacht club) using the term to describe the amount of beer left in a keg that could not be removed. I now realise how wrong I was.
 
Point taken I should have called it "tank bottom sludge" or "tank bottom residue".
Any other ideas on getting it out?
 
I have done and do use a large Pela oil extractor with its largest pipe and PVC tube adding a lump of 10mm fuel pipe on the end - helps to point the effort into the uttermost regions of the tank.

Somewhat tedious as the pipe frequently gets blocked with larger bits of crud (mine's a steel tank). Carefully filter the excess fuel and return to the tank, only rejecting anything that's doubtful.
 
How much do need to get out? Fifty to 100ml?

Unless you want to 'polish' your fuel use secondhand 50ml syringes (from an anaesthetist) and discarded clear plastic tubing from O2 masks. The syringes can be attached to the clear tubing and the sediment aspirated easily through a 1/2 inch plug - although I have had to attach an exterior wire to stiffen the plastic tube so as to direct it to where I need it to go. The syringes only last 3 or 4 attempts before the plunger gets knackered. Allow the aspirant to layer and return the good stuff to the tank.

I do it regularly and am surprised by the amount of gunge/water I get out…and I regularly treat the tank with a biocide and keep it topped up. The fuel dock has had some problems.
 
Many thanks for the tips - Sounds like a Pela and home made attachments will be the way to go. Will let you have any feedback
Martin
 
Last year I waited until I was out on the hard,(to get a decent 'head' of fuel) then syphoned the tank using garden hose with a primer bulb, down through the filler. The "tank" end of the hose was weighted with a piece of lead flashing wrapped round it and could be waggled along the bottom of the tank while sucking.
I only took a few litres out as there wasn't evidence of a problem, but I'd like to do it again with an air hose connected to the engine feed point so as to agitate the crud a bit, although it would involve removing and polishing all the fuel then flushing the tank with something -paraffin?
 
Billjratt said:
Last year I waited until I was out on the hard,(to get a decent 'head' of fuel) then syphoned the tank using garden hose with a primer bulb, down through the filler. The "tank" end of the hose was weighted with a piece of lead flashing wrapped round it and could be waggled along the bottom of the tank while sucking.
I only took a few litres out as there wasn't evidence of a problem, but I'd like to do it again with an air hose connected to the engine feed point so as to agitate the crud a bit, although it would involve removing and polishing all the fuel then flushing the tank with something -paraffin?
Click to expand...

I think agitating the fuel is a bad idea. The water and gunk should settle to the bottom of the tank. It is a good idea to wait until it is really settled ie when on the hard. You might find with a bit of luck that the boat or tank bottom is not level so giving a good point to suck fuel out. Best is to drain all fuel then mop out the bottom. Re the fuel line it is best to simply drain some fuel from the outlet. However this is probably clean. good luck olewill
 
You must log in or register to reply here.

Share this page

Top