Standby/reserve fuel tank

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Having recently read lots on here and other various websites about fuel bug contaminating fuel I was wondering what the collective thoughts were on plumbing in a seperate 20 ltr emergency (get me home) fuel tank.

My current set up (motor boat so no sails) is a single engine and tank, fuel supply filtered by Racor turbine 500 unit and engine mounted factory filter. I have a spare set of engine fuel filters and Racor filters should the worse happen. Having changed the engine filter several times I would not look forward to doing it under stressful conditions at sea given its hard to reach location. The Racor filter is easy to do though.

I have a spare Barrus 20 ltr tank knocking around at home (internals cleaned out) and so my thinking is that I could fill this with fresh fuel, treat with Marine 16, plumb into main fuel tank outlet and isolate it with a ball valve. Then if I ever found myself in a situation of either contam fuel or running out of fuel I could just deisolate the standby tank and use it to get me somewhere safe. An added advantage is I can easily visually inspect the tank and fuel in the standby tank where as I have no way of checking the state of the main tank.

My only concern (not a big issue though) is how long it would last as the engine will still return the unused fuel back to the main tank as the new standby tank is a feed supply only, no return.

What do you think - worthwhile or not?

Cheers
 
If I was going to start replumbing the fuel system to improve bug-resistance, I would be improving the filter arrangements rather than adding a small auxiliary tank. I don't know what engine you have, but I expect it would empty a 20l tank pretty quick, burning some and pumping the rest into the main tank.

The chances are that your on-engine filter can be moved to somewhere more accessible - certainly if it's connected by hoses rather than rigid piping. You can also arrange a changeover system for either or both of the filters, so that you have a standby already fitted and just turn a valve to switch over to it.

I don't know if motorboats routinely have a fuel suction gauge, but if not, fit one. It's only a fiver or so for the gauge, plus a few quid for a T-fitting and some narrow tubing, and it will show you when the filter is starting to block instead of the first warning being when the engine starts spluttering. I usually have a quick look at mine before heading into a tricky pilotage situation or anywhere else that sudden engine failure would be a major problem.

One spare filter is really not enough if you have a serious contamination problem.

Pete
 
Thanks for reply Pete.

Not sure I can move the engine filter as it has a hand pump built into the housing which has some substatial fixings along with hard lines and electrics. I would have thought my first warning would be the primary Racor filter blocking? So I have fitted a DP guage to monitor the condition of the Racor filter like you suggest. I have 5 Racor filters and 2 engine filters. My thoughts were that if I have to start changing filters then my fuel is bad and no matter how many filters I change Im still feeding them with bad fuel. Do you think that if I change filters it would allow further engine running to get me somewhere safe, longer range than the 20 ltr tank would? My thinking was that I could change the primary filter and run from the fresh fuelled seperate tank. That would allow me to run to the tank capacity, hopefully a few miles at least and also provide a safety net if I ever ran out of fuel.
The parts cost for the plumbing is about £30 but a twin Racor filter unit with change over valve looks around the £700 mark.

Mark
 
If the return goes back to the main tank.....................complete waste of time.

If you're set on the second tank you'll have to tee and ball ball the return too. Easy to fit a return to your tank, no pressure involved so you can just Sikaflex a fitting into the tank.

Personally, i wouldn't bother though. Keep your fuel scrupulously clean and keep the tank full. When you return from a trip out top the tank up to the top, stops you getting condensation in the tank.
 
Why not just get a couple of good quality ten litre jerry cans and a jiggle pump? One per month or so empty one of the jerry cans into the main tank and refill so that you always have fresh fuel in the jerry cans.
 
Ric said:
Why not just get a couple of good quality ten litre jerry cans and a jiggle pump? One per month or so empty one of the jerry cans into the main tank and refill so that you always have fresh fuel in the jerry cans.
Click to expand...

And when you find you have a tank full of slime, what do you do with those cans?

Pete
 
PaulRainbow said:
If the return goes back to the main tank.....................complete waste of time.
Click to expand...

This was worrying me a bit. Was not sure of the return rate at idle so was not aware how long the reserve tank would last should I need to employ it. Looks like the concensus is not to bother then.

Appreciate all of your replies. Might put the Racor twin filter setup on my xmas list, see if I have any luck that way.

Cheers
 
I think that would be very wise on a single-engined mobo, Devon.

The ideal:
twin filters switchable, and changeable, on the fly;
regular use of a fuel biocide;
access to the fuel tank for inspection and cleaning;
an easy means to drain fuel (and non-fuel :ambivalence:) from the very bottom of the tank;
free beer for the rest of your life*.

* Well, if we're dreaming, let's dream big.
 
We have just had to dispose of 700+ litres of SERIOUSLY contaminated diesel. It was full of bug, was really dark in colour and had a lot of water at the bottom of the tank-obviously where the bug grew and developed durung the five years the boat was out of use.

To move it to Tommy Neilsons shipyard in Gloucester Docks I extended the feed and return lines and just stuffed them into a fullish 10 litre container of clean diesel. A rag was stuffed around the extended pipes and taped into place and the 10 litre drum secured with a bungy.

Worked fine, and the falling level could be seen through the semi transparent plastic of the drum, as could the depth the feed pipe was at.

So, for an emergency fuel supply a drum of fuel and feed and return extensions are required, plus a method of stopping it falling over and leaking from the cap area at sea. My rag and tape could easily be improved.

Simples..................
 
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Some spare fuel in cans has been very useful to us a few times.
It's enabled us to help other boats who've had problems.

If I was spending serious money on a fuel system I would have a day tank, two storage tanks and a couple of jerry cans.
And sails....
 
macd said:
access to the fuel tank for inspection and cleaning
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I fully agree macd. Why the hell are some tanks so difficult to gain access to for inspection? In an ideal world I would indeed have a large inspection hatch fitted but on my current boat its just not feasible. Even on the 13 life boats at work none of those have decent access to carry out visual inspections. Come to think of it can't recall the 10 year old + diesel in there ever being flushed/cleaned or treated. Must look into that.:ambivalence:
 
I may very well be wrong with regards to the fuel treatment/fuel change on the LBs just Ive never seen it. Will check the maintenance logs but certainly the tank access on the very old LBs are limited. I guess you could use a camara down through the filler neck. I hope they do biocide the fuel then there might be some "spare" stuff knocking around ;)
 
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