Diesel tank Full or empty for lay up?

[Leighb]

As subject.
I am coming out of the water on Monday. Tank is nearly empty, perhaps 10 -15 litres in. Should I fill it up before it comes out?
Or is it worth trying to drain it once she is ashore?

 

[Solitaire]

Fill the tank up. It will prevent the build up of condensation in the tank. Water and diesel don't mix!! Unlike petrol it wouldn't go off over the winter.

 

[sarabande]

If a steel tank then either drain completely and fill with an inert gas such as nitrogen, or fill as full as poss with diesel to avoid the risk of drops of condensed atmospheric water falling into the tank and contaminating it / forming a breeding ground for bugs / causing rust.


If GRP, the rust problem is, err, lessened, but water in diesel for along time is not a good idea. Probably fill as well.

(Look on the costs of a complete fill as a hedge against rising costs of hydrocarbon fuel /forums/images/graemlins/grin.gif)

 

[vyv_cox]

Keeping it full will reduce the likelihood of condensation in the air space above the fuel as it expands then contracts, drawing in moist air. The fuel will not degrade in the time before it is next needed.

 

[Leighb]

[ QUOTE ]

(Look on the costs of a complete fill as a hedge against rising costs of hydrocarbon fuel /forums/images/graemlins/grin.gif)

[/ QUOTE ]

Sounds a good way of looking at it!

tank is alloy, but the water problem is the one to avoid I guess.
Thanks

 

[FAITIRA]

full + an addative for me!

 

[Guest]

I usually leave my tank as is end of season ..

My tank today is with only about 10 litres in a 85 litre tank.

I have been checking up on water sources for tank and one source - Volvo Trucks - cite the fuel return to the tank .... I hadn't considered this factor.
The relevant data is : put into Google ... Volvo P550

and you should get up the data sheets etc. for their additive to clean systems.

I was looking as we are blending / producing an additive for refinerys etc. and we always look at any reference data available big and small ... have to admit some is just plain down-right ludicrous !!

So IMHO .. yes filling the tank and reducing air space is good idea -but moisture content of the fuel and any free water in tank is probably there already. Albeit in tiny amounts.

If you emprty the tank ... you still have what we call clingage .. that will run down the tank sides and collect in the bottom .. albeit a few cl's ... but that cl's is enough to breed a nice colony of bacteria and fungi ...

So we come back to full or leave alone ... Me - I'm lazy - I leave it alone ...

Recently I suffered completely blocked system ... filter and the inlet small filter in inj. pump. I expected to find dead bacteria and fungi ... in fact after all those years of a mild steel truck tank and laziness - I had very little bacterial evidence in the blocking substance - most was sediments and sludge that had accumulated over the years.

It would be interesting to know how many real bacterial stoppages really occur .. as some could in fact be other sediments that have been assumed to be bacterial ...

You could of course dose it with Bug killing additive .. leave it over winter to do its work ...

In fact I am going to try field trial in our 6 litre Mercedes Truck and later my boat tank the additive we produce ... but as with success - you never know if it is really working .. these products you only know about when you don't use and you have trouble ... bit like Rope-Cutters !!

Sorry to ramble on ... but it's a bit like the subject really - you will never have an exact answer - but a lot of opinions ... and that's not bad in itself.

/forums/images/graemlins/wink.gif

Oh and our product is not destined for UK shelves I'm afraid .. unless sufficient demand once launched. So I'm not advertising or trying to drum up biz on it ...

 

[nedmin]

If you dont fill put a plastic bin bag on the breather pipe then it will "breathe" the same air all the time.I tape the binbag onto a suitable piece of rubber tubing.

 

[Twister_Ken]

"put a plastic bin bag on the breather pipe then it will "breathe" the same air all the time"

Ooo-err, that's clever!

 

[AIDY]

empty /forums/images/graemlins/grin.gif it's coming out to get rid of the sludge.

 

[Leighb]

Thanks everyone, as I expected plusses and minuses for both options.

I think I will leave as is, and try and extract the tank in the winter and clean it out, there is definitely gritty stuff in the bottom that I can feel when I dip the tank.

 

[Guest]

A trick to get as much grit / seds out of tank bottom as possible ...

Have your siphon set-up and running ... and also an air suply - Dinghy pump is excellent as it's high volume and low pressure ... --- stick a stiff pipe into the tank and while stirring contents of tank ... give good foot-pump blows of air in ... it stirs up the crud luv'ly ...

 

[FAITIRA]

Good idea!