Fuel tank plumbing

For Grand Banks, Alaskans, East Bay & Aleutian Yachts

Fuel tank plumbing

Postby Sleepah » Wed Jul 02, 2014 8:16 am

Hello all,
I haven't been on the board for a long time and had to contact the moderator because I forgot how to get back on. I still have my GB42 although she has sat idle for 2 plus years. You see the war department (as in wifey) decided she had had enough living aboard in the Bahamas and Florida Keys and insisted that we swallow the anchor and buy a house. So she bought a SW Florida house and I made sure it had a dock capable of holding SPARTINA. And for the last 2 years I have been working on the house and not the boat.

And we celebrated SPARTINA's 40th birthday in the meantime.

To make a long story short, I had a leak in my starboard fuel tank and had a new identical one made. There was a previous owner installed complicated 9 valve fuel manifold on the aft engine room bulkhead. I decided to get rid of it for simplicity sake and ripped out all the plumbing without documenting anything. Now I find that I only have one fuel pick up in the old tank which serves the port Lehman and the generator.

Is it permissible to draw fuel for both a Lehman and a generator from one pick up? Since there was such a complicated valve system I never had occasion to realize that this must have been the way it was before. I also have one entry point for the two fuel returns.



Hmmmm

Thanks
Howard Means
'73 GB 42 CL #362
"SPARTINA"
Punta Gorda, Florida
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Postby roger and anne howell » Wed Jul 02, 2014 9:00 am

Hi,
We have a single GB36, so the plumbing is a bit different, but in our '88 the supply pickups from both tanks lead to a common manifold (a length of about 1' stainless tube). From there, supply valves lead to the engine and the generator, and there are blanked off taps for a second engine if installed. So the engine and/or generator can be fed from the port, starboard or both tanks, depending on how the supply valves on the tanks are set up. We have a CAT 3208 which pumps about 9 gal/hr thru the system (most of which returns to the tanks) and have no problems with a common pickup point.
Roger
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Postby Stretch Head » Wed Jul 02, 2014 9:17 am

Howard, I mean Sleepah

I went through the same change 3 1/2 years ago and we bought a house in Long Beach. My boat sat idle two years and I started replacing my deck last July.

On my GB, the port tank feeds both the port engine and gen. It's never been a problem. That tank holds 50 more gallons too, I think.
Capt Head
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Postby Sleepah » Wed Jul 02, 2014 9:54 am

It's nice to hear from the same people I talked to 2 or so years ago. I remember both of you.

And I am relieved to know that two engines can feed from the same pickup. Just to be clear, my planned plumbing will go like this:

single pick up tube to a tee,

The two output legs of tee go to the Lehman and Westerbeke Racor filters

and the two filters each feed the Lehman and the genset.

Thanks guys,

Howard (Sleepah was my high school name and when I started the GB forum deal I wanted to be anonymous.)
Howard Means

'73 GB 42 CL #362

"SPARTINA"

Punta Gorda, Florida
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Postby Bob Lowe » Wed Jul 02, 2014 10:17 am

The main thing to keep in mind when feeding multiple engines/gensets/heaters from one port at the fuel tank is the possibility of drawing air through one or more of those units. This can fuel starve the main or genset and require bleeding to restart.

Using a buffer, like a larger manifold or small tank, fed from multiple sources/tanks can go a long way to preventing this sort of problem.
Good luck,
Bob Lowe
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Postby Sleepah » Wed Jul 09, 2014 5:33 am

Bob,
My concern is that the Lehman may find it easier to draw fuel from the generator rather than from the fuel tank. But this is the way it was aboard SPARTINA apparently for 40 years, two engines off one pick up tube. Or at least back to when the original tanks were replaced in the 80's.

Any "buffer" tank couldn't have a vent and seems to make things harder to bleed.

I'm thinking that there must be more resistance sucking fuel from the other engine than from the tank so it will choose the tank. But realize that both the genset and Lehman will have to be properly bleed all the time.

Maybe a picture of Roger's manifold would be helpful.

TX
Howard Means

'73 GB 42 CL #362

"SPARTINA"

Punta Gorda, Florida
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Postby roger and anne howell » Wed Jul 09, 2014 11:24 am

Howard,
We're currently underway from Casco Bay to Northeast Harbor, prepositioning for a trip up the Bay of Fundy to Saint John, New Brunswick, the Saint John River and the Reversing Falls. I'll try to get a picture once we sit for a while and the engine room cools down. I think a suitable manifold could be constructed from valves, pipe unions and caps, all available at the local hardware store. I forgot to mention that the generator/engine fuel returns also go to a separate return manifold, which is valved to allow fuel to flow to either or both tanks.
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Postby Sleepah » Thu Jul 10, 2014 7:30 am

Thanks Roger,

I have a friend in Cape Coral who has an Ocean Alexander trawler with these manifolds. I have grandchildren here for a visit but may be able to sneak a look at them today. He has twin Lehmans and a Westi genset just like my SPARTINA.

Isn't it cold up north? I don't believe in cruising north of the Cape Cod Canal due to excessive tides and chilly water. As a kid my parents dragged me north to foggy Maine every summer. As an adult I tend to appreciate warmer climes.

But really, your trip sounds like great fun. Enjoy.


Thanks,

Howard
Howard Means

'73 GB 42 CL #362

"SPARTINA"

Punta Gorda, Florida
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Postby Sleepah » Thu Jul 10, 2014 12:13 pm

Roger,
I did sneak a look at my friends Ocean Alexander 43's fuel manifolds. He has a SS tube about 1.5" diameter by maybe 10" with 5 threaded fittings welded on to hold 5 1/4" ball valves labeled as follows:

port tank, stbd tank, port Lehman, stbd Lehman and generator.

there is also a similar manifold (5 outlets) which serves to route the fuel returns back to the tank.

If this is what you have, never mind the photo.

Bob Lowe mentioned the desirability of a reservoir but I'm not sure why. Does anyone know why boats seem to employ a tank rather than a series of plumbing tees?

TX
Howard Means

'73 GB 42 CL #362

"SPARTINA"

Punta Gorda, Florida
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Postby Bob Lowe » Thu Jul 10, 2014 1:42 pm

That large tube in the manifold is the reservoir in that setup. Kinda small, but workable.
Good luck,

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Postby roger and anne howell » Wed Jul 30, 2014 6:56 pm

Howard,
Just returned home today. Sounds like you don't need pics. We travelled past Maine, up the Bay of Fundy (cold and foggy) to Saint John, New Brunswick. There, you traverse the Reversing Falls when the 30' tide of the Bay of Fundy levels with the river level, about a 10 minute slack tide period. Once in the river, you are greeted with warm (72 degrees) fresh water, no fog and lots of nice Canadians. A real change from the coast of Maine, but a trek thru fog and tides limits the number of visitors.
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Postby Sleepah » Wed Jul 30, 2014 7:08 pm

Thanks Roger,

Sounds like a great trip in a great boat.

I am headed north to Massachusetts (by car) to see family so the boat work is on hold for now. But I believe I have the plumbing in order.

Thanks,

Howard
Howard Means

'73 GB 42 CL #362

"SPARTINA"

Punta Gorda, Florida
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Sleepah
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