Sucking water from diesel tank

[smithy]

I want to extract any water that may be lying at the bottom of my plastic tank. There is virtually no access at the top as its hard against the deckhead and the filler pipe has a double bend in it.
The first method I thought of was putting a weighted flexible tube down the filler and attaching my extractor to it.
Second method was to try feeding a hard nylon tube into the supply pipe and then down on into the stand pipe which goes to within an inch of the bottom.
Any thought or tried and tested methods?

 

[Bilgediver]

Just have to use whichever method suites your boat. As the water sits below the fuel it helps if you can get the corner of the tank you are using to be the lowest part by altering the list and trim of the boat. Might need to tempt a few heavy weight friends to a party.

 

[Boater Sam]

Wet and dry vac with a length of rubber hose on the end?

 

[penberth3]

Wet and dry vac with a length of rubber hose on the end?

Do you really want diesel in your lovely wet and dry vac? I wouldn't.

 

[smithy]

I've got one of these its getting access to the base of the tank that's the problem.

 

[Boater Sam]

Do you really want diesel in your lovely wet and dry vac? I wouldn't.

I do it all the time, have a dirty vac and a clean one. The dirty one sucks up sump oil, sewage, fuel, etc.

 

[WoodyP]

Do you know that you have water beneath the diesel? I would run the diesel right down first, then use a diesel additive for removing water. If you can't get access it's your only option.

 

[AndrewB]

I used to run down a thin pipe stiffened with a piece of wire (a dismantled clothes hanger), through the top filler. Bending the wire enabled me to suck up from the deepest point, below the bottom of the fuel feed pipe to the engine. Also move around a bit at the bottom. Always a lot of grot came out as well as a little water, and sometimes diesel bug jelly. (That incidentally, despite regularly treating the fuel. But the diesel bug never got as far as the primary filter on the engine).

A couple of years ago I took a look right under the tank, via the bilge. Not easy to do, but with the aid of an inspection mirror, discovered a recessed drain bolt. Maybe you have one too? Its quick to drain off water and diesel bug that way, but opening the bolt in such an awkward spot is really tricky without flooding the bilge with diesel. One day, I promise, I'll fit some sort of stop-cock there.

 

[Bilgediver]

Just have to use whichever method suites your boat. As the water sits below the fuel it helps if you can get the corner of the tank you are using to be the lowest part by altering the list and trim. Just need a few weighty friends to adjust list and trim so the suction hose is at the lowest corner of the tank.

 

[William_H]

I would go for OP option of a flexible tube weighted so tube sucks from lowest point. ie something like a block of lead with a hole through the middle for the tube to be attached. (firmly you don't want to lose it) Cut some grooves on under side of lead to get fuel into tube. You coud try a tube inside the normal pick up tube but seems tricky to me. ol'will

 

[thinwater]

Wet and dry vac with a length of rubber hose on the end?

I witnessed the aftermath of this practice (warehouse attached to my office building). No serious injuries, but the tank was toast and the operator was thrown.

A vacuum generates a flammable mist. Most of the the time you can get away with it.... I also saw a man toss a lit cigar in a diesel tanker to prove it would not light. Doesn't make it good judgment.

 

[thinwater]

Deleted

 

[jwilson]

Unless the boat is brand new 99% sure you will find some water in your tank, probably black plus some thicker muck. Is your plastic tank thick smooth plastic a la TekTanks or thin rotomoulded?

 

[SaltIre]

I've got one of these its getting access to the base of the tank that's the problem.
View attachment 134464

That was my first thought. Does the tank have an air vent that could be used?

 

[CM74]

I would go for OP option of a flexible tube weighted so tube sucks from lowest point. ie something like a block of lead with a hole through the middle for the tube to be attached. (firmly you don't want to lose it) Cut some grooves on under side of lead to get fuel into tube. You coud try a tube inside the normal pick up tube but seems tricky to me. ol'will

One of those clunk things that are used in RC plane fuel tanks or strimmer tanks would be ideal and a less likely to fall off
You can usually buy them complete with a length of the very flexible silicone tubing they use so it should find its way right to the bottom.

On my boat I tried a length of thin copper pipe as it's straight down from the filler, it got to the bottom but I couldn't get it into the corners, so I think Flexi tube and a clunk weight should do the job

 

[Plum]

Unless the boat is brand new 99% sure you will find some water in your tank, probably black plus some thicker muck. Is your plastic tank thick smooth plastic a la TekTanks or thin rotomoulded?

Then I am lucky to have none in the bottom of mine (metal tank 22 years old)

Www.solocoastalsailing.co.uk

 

[Oily Rag]

I have a dedicated plastic tank for the Eberspacher. It is opaque, but a high power torch held against it shows not just the fuel level, but the muck and debris level at the bottom.

I use a small-bore copper pipe to get to it and connect up to a cheap pump. A large pipette would do just as well.
Good luck!

 

[jwilson]

Then I am lucky to have none in the bottom of mine ☺ (metal tank 22 years old)
Www.solocoastalsailing.co.uk

If you have never had to clean it out - where on earth do you get your fuel? I'm sure water comes in with the red diesel in my tank, which has now been cleaned out 4 times in 18 years from new. First time at 10 years, a pint plus of black water and muck, less on each subsequent more frequent cleaning.

As the water/muck lies on the bottom and the draw pipe is well above this, I've never actually had anything drawn into the filters despite clearly long periods and many miles with water and black jelly in tank.

Next time I'm on a shiny new boat at Southampton Boat Show I'm minded to ask "... how do you clean the fuel tank?". My 2004/5 Jeanneau tank was clearly designed never to be cleaned or drained. I had to make significant modifications to allow it, and even after this it's a half day job to do it.

 

[colind3782]

I just sucked everything out into large plastic containers using a Lidl electric pump and happily found no water. Filtered the diesel and stuck it back in the tank.

 

[SaltIre]

I just sucked everything out into large plastic containers using a Lidl electric pump and happily found no water. Filtered the diesel and stuck it back in the tank.

How did you get past the S bend in the filler pipe?