To fill, or not to fill?

[roberth]

I'd be interested to hear the panel's views on topping up with diesel.

I last filled up with diesel before laying Karsha up in January. So far this season I have had little need to use the engine, so the tank is still half full.

I always use additive to stop bug growth, and the fuel remains crystal clear.

As far as I can tell (by sucking fuel from the bottom of the tank) there is little, if any, sediment in the tank.

My question is - should I leave half full and continue to burn the old fuel, which I gather has a shelf life of about 3-6 months (not that I take much notice of sell-by dates)? It could take a month or two yet, if winds stay fair.

Or does this leave it at greater risk from water contamination through condensation? If so, would it be better to top up to mix it 50:50 with new fuel, even though this would potentially leave some older diesel in the mix for several months to come?

Any views - even from Starboard /forums/images/graemlins/grin.gif - would be welcomed.

 

[smeaks]

top up while it still untaxed! ...and to avoid condensation and unecessary slopping around with all the extra freeboard in the tank.

 

[cliff]

Forget Starboard - I suggest you sell the boat and take up knitting instead. Or is this a TROLL? /forums/images/graemlins/grin.gif
--------------------

"Artificial intelligence is no match for natural stupidity"
sailroom <span style="color:red">The place to auction your previously loved boatie bits</span>

 

[KevB]

Is it petrol or diesel? Don't think diesel has a shelf life?

Just re read and see it's diesel. I wouldn't worry but would probably top it up to keep the moisture to a minimum.

 

[Guest]

Re: To fill, or not to fill? Oh Dear ....

If you don't top up you will suffer all sorts of engine failures, blocked - destroyed filters .... engine will have to be stripped and completely overhauled ...... and the Gods will curse you till Hell freezes over.

Right the above "tirade" is about as true as the rubbish you have been told about Diesel Shelf life ...

Who the hell told you that absolute load of hogwash ?

If fuel is clear, you have near zero sediments ..... be happy - you are on a winner !!

 

[Piers]

Re: To fill, or not to fill? Oh Dear ....

Always keep diesel tanks topped up. No problem with old fuel. Part filled tanks allow condensation to occur on the tank surfaces which runs to the bottom of the tank and causes mayhem.

 

[roberth]

/forums/images/graemlins/shocked.gif

 

[andy_wilson]

I don't fill up all season, until the Autumn nights start to get colder, then I fill up and top up, to prevent condensation.

 

[l'escargot]

Condensation and fuel bug is a bit like osmosis - a constant topic of conversation for the neurotic. /forums/images/graemlins/laugh.gif In a small tank on the average sailing boat, the amount of condensation you are likely to experience can be more than matched by a water trap in your primary filter.

Fill up your tank when convenient, change your filters at the start of each year, keep an eye out for any water in the bottom of your water trap and get on with life. Diesel doesn't go off.

 

[shamrock]

Having two 400 litre tanks, I top up every month just so that I don't have to fill up all in one go which would let SWMBO see the large numbers on the pump....

in autumn, top up to keep condensate free.

 

[Heckler]

my man, a breath of fresh air!

 

[andy_wilson]

To the above 2 to replies...

I have a yacht with a mild steel tank, with sump and drain that is accessible, and has a pre-filter with a water trap.

I have never, ever had any sign of water in the glass bowl of my water trap.

I have periodically drained silty waste via the tap in the sump at the bottom of the tank.

Despite the above, and despite the yacht being well used (for this purpose lets say agitated), water in the fuel tank still managed to ledge in a forward corner rather than the sump, and rust it's way through, depositing 2/3 of the contents into the bilge by the time I made my next visit, which was early spring to commence re-commissioning.

I am fortunate that the water tank could be removed without major dismantling, squeezed forwards past the gearbox and sideways through the access hatch into the stern locker without butchery (other than to my knuckles). The surround for the locker lid however would have required de-glassing to remove the lid and frame assembly to get the water tank out of that space, and out of the way.

The fuel tank was removed with some difficulty, working, as I was with a water tank, in a now tight cockpit locker.

More fortune as the fuel tank came out through the locker, by manouvering the water tank around in the style of one of those tile puzzles that require several moves before you can get the bit you want, to the place you want it. Clearly the replacement identical tank threw up similar challenges.

The deodourising of the yacht interior was a mammoth task. ENDLESS!

If you have a plastic or s/s tank, good luck.

If you have a mild steel tank, make your own luck. You may want to invest a little thought into the management of the condensing space above the fuel, and routine maintenance of the contents. I was lucky, plenty of yachts require major GRP surgery to remove tankage, I got away with none.

I hope this is of a little more use than a simple dismissal of the problem.