That is why I used only two 3 way valves. When the engine starts sputtering
you open a little access hatch under the helmsman and turn them the opposite
direction they are in. Then you can change filters at your leisure. Even
if over time the diesel etches the valve surfaces the leakage between
filters will be minimal and not effect their operation.

There are 3 other valves below deck that allow bypassing the day tank and
drawing directly from the port or starboard storage tanks but they are
clearly marked and only needed if the low fuel alarm on the day tank or the
transfer pump fails.

The day tank holds 24 hours of fuel at normal cruise. All fuel entering the
day tank goes through a pair of 1000FG filters with 10 micron filters and
water sensors in the bowls so all the fuel is filtered rather than a
recirculating polishing system that filters the same fuel over and over.

Now for the complicated part: I programmed a microprocessor to track the
gallons drawn from each storage tank and the content of the day tank but it
has nothing to do with the ability to transfer fuel. If it gets fried the
only thing important I loose is the low fuel alarm on the day tank.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Wayne.B" wrote in message
news
On Tue, 09 May 2006 13:17:35 -0700, RW Salnick
wrote:

It is certainly true that with a pump or two and 10 or more
valves, you can set up for almost anything. But will you get it right
in the middle of the night? Years after you designed the system?

Good points. Speaking from personal experience, it is very easy to
open or close the wrong valve in the heat of battle (big seas,
sputtering engine, etc.). That is a bad time to accidently introduce
air into the fuel system. Don't ask me how I know. :-)

In addition to keeping things simple and intuitive, it is important to
rigorously follow a tried and true procedure so that no ad libbing is
required. It is also worthwhile to invest in a nice set of engraved,
color coded labels for non-obvious valve positions.