Fuel Management Question

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Senior Member
May 10, 2011
Vessel Name
Golden Dawn
Vessel Make
Krogen 42
I have a question about fuel management. I have four diesel tanks on board, two 250 gal and two 150 gal. I have a good fuel manifold and transfer pump (see photo) that allows me to move fuel around. Presently, I do not have a filter in the transfer pump but could add one to act as a polisher. I use biocide on each fill-up and have not experienced any unusual filter clogging on my dual-Racor system. I am not convinced that adding a filter to the transfer pump would be helpful as my experience is that sediment if going to be stirred up while rocking and rolling underway, when I am unlikely to be moving fuel around.
Last year, we were in the 200 hr range for vessel usage and at <2 gal/hr, I used a maximum of 400 gal. When running, I usually switch tanks daily so I am turning over fuel in each tank. Bottom line is that I have old fuel on board some probably more than a year old. Prior to summer, would you recommend mixing it all up via the transfer pump or continue on my daily cycling from tanks to tank ? Or both? How do others manage their fuel?
[Photo - return manifold top, supply manifold bottom; Racor is actual for the genny not the transfer pump, which is at right.]

-- Edited by GoldenDawn on Tuesday 28th of February 2012 12:36:33 AM


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I don't completely understand your quandry.* If you're moving fuel from tank to tank daily, wouldn't the fuel end up mixed if there is any fuel in the "target" tank?

Without filtering, I see no advantage from moving fuel around except to balance the boat's weight so it stays level.

Might as well filter/polish the fuel while you move it.* Expect the rate of fuel movement to be slowed going through filters.


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GoldenDawn wrote:How do others manage their fuel?
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*We don't have transfer pumps or any of that stuff. With the exception of the mechanical lift pumps on the sides of the FL120s, our entire fuel system operates with gravity only, and all tanks drain/feed from their lowest points.

We have four saddle tanks, two on each side, that we transfer fuel from (via gravity and manual valves) into a day tank in the middle of the engine room under the floorboards.* The engines and generator feed from the day tank although the engines can be valved to pull from a saddle tank on the engine's side of the boat.* But we have never had occasion to do this.

Our fuel managment process is to transfer fuel from one opposing pair of saddle tanks as needed until the two tanks are empty.* We then leave them empty and transfer from the other opposing pair of saddle tanks until they are about 1/4 full.* At that point we fill the empty pair of tanks and continue drawing down the second pair until they are empty and then we leave them empty until the first pair we refilled are 1/4 full and then we repeat the process.

The only times we fill all the tanks is before a longer cruise, at which point we begin the above process again.

We do this for two reasons.* One, to minimize the time fuel sits around in the tanks and two (and more important) to ensure the tank seams/welds (the tanks are stainless) get exposed to oxygen on a regular basis.

But based on everything I've ever heard or read, your one-year-old diesel should not be an issue at all assuming it was clean to start with and hasn't accumulated water.* If it was us, we'd just use it in the normal manner.
You might consider running with only the small tanks , and leaving the larger ones empty.
Golden Dawn -- I see no problem with what you are doing, nor do you say you have one. Don't confuse diesel with the gas and methanol issue that gets all sorts of press.

I'd not mess around with a fuel filter on* your transfer pump so long as your filtering system in front of the*engines is working OK.* As stated by others, buy good fresh fuel and you should have no issues. Keep it up and cruise happy.
I would install a filter before the pump to protect the pump and to keep any contaminates with one tank instead of contaminating the othrr tanks.***Most diesels draw more fuel then they use so they return fuel to the tank, so the engines are cleaning/polishing the fuel also.*Our DD 671 draws about 50 gallons/hour but used 4 for 5 gallons/hour.* So if you are run 200 hours the chances are the fuel is clean.
Diesel will last more than a year even a couple of years.*The new ultra low sulfer and now the bio diesel does not last as long so I try to trun the majority each year.**However, I am concerned about moisture in the tank and the water separating from the fuel.* So the additives I use absorb water back into the fuel.* No water, no rust and no bugs.*

Anyway I would added a transfer filter before the pump to at least protect it, and maybe some additives to before filling up again.*
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