Fuel Tank Pickups for the Generators.

[riverrandy]

I have a call into the "expert", but wanted to see if anyone here might know the answer. My boat is an odd, "rear engine room" boat. There are two main tanks, one forward and one aft. I have the tank lay out schematics, but they do not really point out the pick up and return for the 2 generators. I have two 3/8" copper tubes that come out of the ER bulkhead next to each generator. I had assumed pickup and return for one tank for either generator. I wanted to figure out which side pulled/returned to which tank.

You see one generator is dead, and I am building a manifold so I can run the good generator off either tank.

So I crawl down and find plumbing all over the place. It took me a while to comprehend, but I found (I THINK) both pickups (supply to generator) comes from starboard side and I must assume both returns are on the port. does that make sense to anyone?

Finally the big question...does any one have a fool proof way to figure out which pipe goes to witch tank, and the same for returns.

Thanks in advance.

[Fanfare]

In general all fuel pickups and their returns go to the same tank they came from. This will prevent overfilling of any other tank and subsequent overflow of fuel via its overboard vent. Not just expensive but now illegal!

Some boats can have cross-linked fueltanks but generally for smaller tankages. The Hatteras Yachts I know of have separate tanks and hand operated fuel manifolds permitting each engine to draw from one or another tank (depending on model) but always be sure intake and rerturn are to the same tank. Many boats have their generator draw and return from only one fuel tank. This tank is usually somewhat larger than the non-generator tank(s). Your Owner's Manual (available from Hatteras) should list various tankages for your boat.

[Captain Ralph]

Of my limited observations of Hatt MYs; Gen-set supply and return go to the same tank. Easily identified by their smaller tube diameter.
On a few MYs we have worked on to this level, only the forward tank was used for the gen-sets.
How to test or prove it?,, With compressed air, blow backwards on the lines from the gen-set. You should hear the bubbles and / or noise at the tank service plate. Not a full 90CFM blast, just enough to make some noise.
C.D. Piner at Hatt support should be able to help identify the lines also.

BTW Some pick up tubes have screens on them. A lil air blow back could be of help also.

[riverrandy]

Thank you to the few that responded. C.D. Piner was who I was waiting to hear back from. He had the tank and plumbing schematics and sent them too me. It turns out having 2 generators I have a set of pick ups and returns from each tank going to one or the other generator. only issue is the individual who ran the supply and return lines did NOT follow the plan. both returns go to the port side of the ER, and both supply lines go to the Starboard side. I was able to find where these attached to the 2 tanks, so I used light compressed air to determine which one was which. It sure is nice having someone like CD and his 45 years of experience to call upon.