Emergency fuel supply/tank

[pcatterall]

There have been a few reports recently concerning fuel issues. Mucky tanks, bug, muck stirred up by rough weather and problems in the fuel lines. I read that in its various forms its one of the biggest issues in engine failures and subsequent calls for assistance.

I would like to feel confident in my fuel system and will certainly endevour to get the system in the best shape I can.

I have wondered about the day tank idea and certainly like it in principle; pump up a days supply into a small (easy to clean)tank via a filter and feel confident that your supply is at least clean.
If the tank is high up then gravity may help as well.

If I can't install a tank like this then is it worth considering how I could/would jury rig something?
A 'jerry can' of fuel that I could jam into a locker with a dedicated hose that could by pass the filters and fit straight onto the pump or something on these lines?

I'm working on the assumtion that at sea it might be more expedient to be able to bypass the system rather than have to tackle several filters, connections etc while trying to identify then rectify a fault.

Has anyone else had to jury rig a fuel supply and would it be worth thinking ahead as to how one would do it on ones own boat and having the simple materials on board to do it?

 

[nimbusgb]

I've had engine failure due to 'the bug' once and a second time I caught it prior to any problems. ( having had the experience once one tends to know what to look for! ) A mate had engine failure due to 'the bug' two weekends ago when his tank was agitated by vigorous weather.

What you are proposing strikes me as sensible with some reservations. You have to remember that diesels tend to have a loop system. The fuel pump delivers more fuel than the engine can handle and there is a return feed to the tank so this has to be handled too. I have a 25 litre jerry can of fresh ( filled before each cruise ) petrol station diesel in the cockpit locker. Along with that I have a length of tubing that could be popped into the filler and hooked in to the fuel input line. The return line would have to be unhooked and also fed into the jerry can, perhaps 20 minutes work.

A day tank might be a good bet with both feed and return lines permanently rigged to it and a manual or electric cross feed pump but you need to prevent a contaminated main tank from affecting the day tank. A second sub 30 micron filter and separator would be needed in that feed. A way to fill that tank from a jerry can would be a good idea in case the main tank was 'bugged'.

Although the day tank may be easier to clean, it will probably be the one that stays bug free ( can be left virtually empty when laid up and gets circulated and filtered much more effectively ) whilst the main tank is still the one that grows the bug.

So tank, pumps, filters, piping etc starts to sound pretty expensive - £200 to £300 at least I'd have estimated. As an alternative I now inspect the fuel in the tank more frequently, visually and by draining off a bit from the tank bottom. Keep spare filters handy. Use soltron to dose the fuel ( the bug doesn't grow overnight )

I have considered building a fuel polisher. A good electric pump ( ebay ), water separator and fine filter element. 'T' off the main inlet and feed back in to the tank, just run it off 12v when the engine is running. Saves the expense, space and hassle of a day tank and addresses the real problem, bug in the main tank!

 

[prv]

I wouldn't feel very happy running an engine even temporarily without filters - you're one bit of muck away from needing a new injector, or even a very expensive injection pump repair. So your temporary system probably needs a filter of its own.

I don't have a whole backup system, but I do have a quick-change filter manifold that I put together. Two primary filters, one in use and one standby. Move two valve handles to switch over to a new bled and primed filter. I'd aim to replace the old one at the earliest opportunity (I carry several spares) in case there's an ongoing problem and the new one also gets blocked. The change is relatively easy because the changeover valves also isolate the non-active filter so there's not much airspace to bleed.

I also keep the fuel hose offcuts from the installation (some quite long) on board for jury rigs.

Pete

 

[r_h]

I don't have a whole backup system, but I do have a quick-change filter manifold that I put together. Two primary filters, one in use and one standby. Move two valve handles to switch over to a new bled and primed filter. I'd aim to replace the old one at the earliest opportunity (I carry several spares) in case there's an ongoing problem and the new one also gets blocked. The change is relatively easy because the changeover valves also isolate the non-active filter so there's not much airspace to bleed.

That's my preferred option - it's standard fit on a lot of mobos as it allows the engine to be restarted using the standby filter with a minimum of downtime - often as little as 30 seconds, providing the changeover switch is reasonably accessible.