Cross over line for fuel tanks

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BillyK

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I live aboard in the north east and installed a diesel heating system. The burner only runs off the port tank. My two 250 gallon fuel tanks are under the berths in the aft stateroom about six feet apart. I have access to the rear of both tanks. I want to get the tanks to self level in the winter and to be separate when the heater is not being used.
What parts should be used to tap into the side of the tank and crossover to each side with a shut off. I have never brazed, but I can flare copper tube and sweat pipe.

Thanks,

Billy K.
 
Sounds like a lot of work just getting the tanks emptied and purged. I wouldn't even want to try doing the brazing in the boat. You can also braze with a TIG.

I just had a thought. If the tanks weren't going to be used for the engines during off season, you could connect pick-up tubes and as long as you could prevent air from getting into the tubes, It would act just like a siphon and the fuel would equalize between tanks.
 
Do you use that much diesel heating your boat, relatively speaking? I lived one winter in a cabin in Virginia heated by fuel oil (and it got pretty cold), and I got by burning much less than I thought.

Just wondering.

V/R
 
I get what you are trying to do but still would worry about cross contamination. Would it be better to tap into the other tank and use a tee and some valves to alternate between tanks to balance it off? I am sensitive to this because I currently have one contaminated tank and with your proposed set up, I would be dead in the water.
Jim
 
Thanks for your thoughts.
I don't need to get to the bottom of the tanks, only about a quarter of the way up.
I use about 3 gallons a day.
I don't want to do a jury rig job, if I can't do it right I don't want to do it at all.

There is no other way to tap into the tank except for brazing a fitting in? If not then that is the way I will go. I know some welders who know how to use a TIG welder. I even have one, I'm not good enough to use it in this application.Billy K.
 
if the boat doesn't already have one, install a fuel transfer pump. if the tanks don't have a separate pick up for this, use the existing engine pickups with Tee's and a pair of valves. the transfer pump should be isolated when using the mains.
 
Often you can't use a pick up to pump fuel back because there could be a syphon valve in the pick up.

If yours don't have that then the easiest way would be to tee in the fuel lines near the pick ups, put valves and a fuel pump to transfer fuel. If you have anti syphon valves it is a lot easier to add a extra one than putting a fitting near the bottom

I am not a big fan of brazing fuel tanks inside a boat :) even diesel.
 
For an experienced tank welder welding on a fuel tank is a safe, everyday job.

But installing a pump might be the easiest thing you could do.
 
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