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From: Norm of Bandersnatch (no email)
Date: Thu Nov 09 2006 - 09:30:40 EST
The situation described below is a direct and obvious result of not sucking fuel from the very bottom of the tank(s). By having the suction a bit above the tank bottom water/glop will accumulate until it reaches the level of the suction line and then wait until rough conditions stir up exactly as described.
The best is to arrange the tanks (build or modify) so as to have a well in the bottom where water/glop can accumulate and then suck your fuel from the bottom of this well, as I have done in my boat. This will insure that you tank contains only fuel, as it should.
Second best, and still far better than the normal practice of sucking from 10% above the bottom of the tank as recommended in a Detroit Diesel installation handbook I have. This practice is left over from the days when yachts carried professional engineers who routinely opened the drain cock of the day tanks daily to drain accumulated water/glop. The idea is to extend the dip tube, using fuel hose is one way, so as to suck from the very bottom of the tank to minimize the accumulation of water/glop as much as possible.
In addition, glop will accumulate on the sides of the tank. This can be corrected by spraying fuel, heated if possible, on the glop to wash it off. Of course, to do this it will be necessary to have a port to gain access to the interior of the tank, a rare luxury in these days of built-it-cheaper consumer products. Personally, I don't find this necessary, probably because there is no water/glop in the bottom of the tank, because of the well, so that any glop falling off the walls is easily handled by the primary filter. Futhermore, the primary filter, because of the gauges, can easily be checked at any time to see how much it is plugged and because of the priming pump, isolating valves and fixed floodlamp on the fuel service area, the element can be changed in less than two minutes.
My primary filter is a Racor 1000 and I recommend it from my experience. The filter elements cost 10 to 13 USD depending on source. I use maybe one every 500 miles but have not kept formal records.
I imagine the paper towel filters will work as well. I investigated them once and was impressed by the high cost of the filter housings compared to the hardware you got. The hype about how wonderful they were laced with loads of testimonials, etc, and seemed as excessive as the price. They seemed to concentrate on selling you "sizzle" rather than meat so I went with the industry standard Racor. The Racor also has a spin type water remover device on the bottom with a clear globe that lets you see the fuel which I appreciated.
While either type primary filter is vastly superior to none, in my view the design of the entire system is the key to the trouble free fuel system.
Norm
S/V Bandersnatch
Lying 30 07.7N 081 39.6W
Julington Creek Estuary FL
As far as brand, I recommend the Gulf Coast Filter (GCF) system. The first time I used the F-1 GCF on my 30' boat I cleaned out roughly a gallon of black goop from both fuel tanks. The boat is 24 years old and over that time a lot of junk had settled in the tanks. I bought the GCF filter after going through some rough water and having a newly installed Racor filter clog and shut down one engine while underway; the second engine began to run marginal also due to a Racor filter beginning to clog. The GCF can accept a large roll of Scott paper towels as the filter medium so a filter change is inexpensive, compared with Racor filters.
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