List: trawlers@lists.trawlering.com
From: Scott H.E. Welch
Re: T&T: Diesel Fuel system design
Thu, Oct 11, 2007 3:01 AM
"Mark Andrew" writes:
>I'm rebuilding an engine room from scratch on a 56' steel trawler (circa
>1955). I've spec'd out Racor filters and the ESI polishing system and will
>have several manifolds sending fuel from one of assorted fuel tanks to the
>various fuel 'users' (main engine, gen set, furnace), and again with their
>'return' lines.
I've just finished rebuilding a 60 foot trawler, including a complete
rewiring and replumbing of the engine room (you can see some pictures at
www.islandeagle.net, sadly the website is wayyy out of date). She has a
single engine, a single genset, a single heater, and two fuel tanks.
You're going to get a bunch of answers to your query, mine might be a bit
different.
First, I started out with plans much like yours. A supply manifold, a return
manifold, the whole nine yards. I then got some advice from a couple of folks
I trust a lot, including a commercial ship engineer and a Transport Canada
inspector who's also a captain with 35 years of experience. Here are the high
points of my system:
1) No supply manifold. I have a single two way valve that lets me select
between port and starboard tanks. All consumers are fed from that selection.
Dead simple, and it's pretty hard to come up with a real-world example of why
you need a more complex system.
2) No return manifold. Again, a simple two-way valve which let you return to
either port and starboard tanks.
3) A real transfer and polishing pump. I used a Jabsco centrifugal pump rated
at about 250 GPH. Way better than a fuel pump. It's on a timer and runs
through a set of Racor 1000s.
4) Separate supply and transfer ports in the tanks. The supply lines exit 6"
above the bottom of the tank, the transfer ports are located at the very
bottom. Polishing will catch the gunk long before it gets to the supply ports.
5) Coast Guard approved fuel hose with JIC fittings. I used Parker hose with
Parker field-attachable fittings (steel, not brass). This is not cheap,
usually. I got mine on eBay at about a 80% discount. It's been perfect so
far. Hydraulic hose will work perfectly well, for less money, but you will
never be able to use your boat for passengers. Something to consider.
6) I used Racor 1000s for the main and Racor 500s for the genset and furnace.
Overkill, but I picked the whole bunch up on eBay for a good price. One word
of advise, don't forget that the Racors need very special o-ring boss
connectors.
6) One last little tip: based on advise from a friend, I put in a bypass
running from the outlet of the transfer pump to the inlet of the main engine
filters. By turning on the transfer pump and closing the tank valves, I can
prime the main engine just by cracking the bleed screw of the secondary
filter. Works like a charm. I've also added another valve and hose to the
transfer pump so I can fill jerry cans (I have a diesel in one of my dinghys).
Hope this helps. More details are here:
http://www.islandeagle.net/systems/fuel
Scott Welch
Product Manager, FirstClass Group
"If we continue to take an eye for an eye, then surely the whole world will
go blind." - Gandhi