TWL: Fuel Polishing installed

Flotsam flotsam at
Sat Dec 30 10:59:16 EST 2000

I installed a fuel polishing system the week before Christmas, pretty
much as Capt'n Wil describes on TWL. 

It CAN be done by a fumble-fingered novice. We had a dealer configure
the system (i.e., recommend how to arrange valves for routing fuel to
and from tanks and engines) for our three tank, twin engine w/genset
GB36. The dealer ( -- usual disclaimers)
was not local -- we made all the arrangements by e-mail. They shipped
the filters, plumbing and other hardware, and hoses, together with a
pretty useful and clear step by step instruction booklet. They also
did much of the pre-assembly on valve manifolds, at no extra charge. I
don't think we paid any more than if we had bought the components at
discount houses, and the parts supply was 95% complete when we
started. (I had to get some copper compression fittings locally, as
some fuel lines were different sizes than I thought, and I had to get
extra fuel line, because I changed my mind about where I'd install
things once I started. And I had to get a fuse. Otherwise, we got what
we needed in the "kit".) 

The biggest problem was not what to do, but where to do it. A GB36
with twin Lehmans and a large old Onan doesn't have all that much
space! The installation itself was pretty straightforward. The
instructions the dealer supplied were sufficient -- we only had to
call once, to find out the recommended size of a fuse.

The configuration has two groups of manifolds. The simpler one also
has vacuum gauges so it's easy to anticipate when filters need to be
changed. This manifold allows me to send all fuel through the F1
(large Gulf Coast Filter) and then through the Racor. I can cut the F1
out of the system if necessary by turning a couple of valves. I can
also shut down all fuel flow here if I want. If I want to, I can
bypass both filters -- probably useful only when transferring fuel
from tank to tank.

Because I want to be able to occasionally see these gauges while
underway, I decided to mount this manifold on a bulkhead in the fwd
head rather than some place in the engine room. Besides -- there just
ISN'T space in the engine room! (I'll install something like a
medicine chest to cover the manifold and keep guest fingers off the
valves in the spring.)

The second set of manifolds is really the "brains". The fuel from all
three tanks goes here, and is either shut off or routed to the filter
manifold I mentioned above. What comes back from the filter manifold
and what comes back from the engines -- clean fuel -- is then routed
to the fuel tank from which it was taken (unless I am transferring
fuel from one tank to another, which requires just a couple of valves
to be turned). I can also isolate one or more engines if need be.

To put all these valves together where I can easily see that I have
the reurn going to the supply tank, and where I can change tanks as I
wish, suggested that the whole set be mounted together. The dealer
suggested a layout to make it somewhat intuitive what went where, and
supplied a sheet of marine plywood for mounting. I cut that down to
about 15" x 30", and mounted the whole thing at the back of a cabinet
under the sink, in the aft head. It's also accessible underway without
getting into the engine room, and it's using otherwise unused space.
Also, this was closest for running the many fuel lines to the
manifolds. I used about 150 feet of fuel line -- it would have been
500 feet or more if I mounted the manifold somewhere forward.

I had worried about the fuel hookups, but they were simple, once I
had the manifold layout done. Find the fuel line going to each engine,
intercept it, and substitute the new fuel supply line from the
manifold. Find the return line coming from each engine, intercept it,
and substitute the new fuel supply line to the manifold. Do the same
for the tanks.  Done.  Then remove 50 pounds of old fuel line and
valves at your leisure.

The only electrical connection was 12V to the continuous duty pump
(via a 12 hour timer). This pump PULLS fuel via vacuum through the
filter system, then PUSHES clean fuel to the engines, with excess
clean fuel being returned to the tank. Running at anchor (engines shut
down) just cleans fuel continuously. The pump takes a 5A fuse.

Finding space for the big F1 filter was tricky. It wants about 40"
vertically, for mounting plus clearance for changing filters.  There
just wasn't any such space. So we built up a mount forward of the
genset, about centerline, and set the filter under the part of the
cabin sole that will normally be lifted out when working in the engine

Photos of the project are at -- you
might notice that I also put bypass filters on my engines and genset.
That project was so simple that it doesn't deserve a separate message.
"T" off the oil pressure sender to get dirty oil, and return clean oil
to the oil pan, using a replacement oil drain plug the dealer
supplied. (I had an inaccessible oil drain plug on one engine, and the
dealer had 4-5 alternate solutions when I called.)

If I could have mounted everything together in the engine room, the
job would have taken me under a day. If someone had done it before,
probably 3-5 hours. But I spent about 30-40 hours, mostly because I
split the system into pieces scattered all over the boat, to deal with
space limitations, and to deal with my own goal of having easy access
to all the valves while underway, without having to get into the
engine room. I had a carpentry-skilled friend help -- it's a 2 person
job if you are running fuel lines through bulkheads. Otherwise, one
person is enough, I think.

The first 2 hours of running on the new system gave no surprises --
it all worked as expected. See Capt'n Wil's articles for more on what
to expect.

I won't be cruising until the spring, so further results will have to
wait. But I thought members might like to know that the process isn't
as hard as it might seem to a novice like me.

Feel free to send questions. (I'm travelling for the next 2 weeks, so
replies might be intermittant.)

Bill Sholar

Pronunciation: 'flt-s&m
Function: noun
Etymology: Anglo-French floteson, from Old French floter to float, of
Germanic origin; akin to Old English flotian to float, flota ship
Date: circa 1607
1 : floating wreckage of a ship or its cargo; broadly : floating debris
2 a : a floating population (as of emigrants or castaways) 
  b : an accumulation of miscellaneous or unimportant stuff 

More information about the Trawlers-and-Trawlering mailing list