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The ability to transfer fuel from the starboard tank to port tank can increase the range of the NT-37 by about 24 hrs of run time at 8 knots/2 gph. A Racor 500 filter provides filtration during transfer and ability to polish fuel recirculating to either tank. The system pulls fuel from the crossover line and returns it to the port tank directly or to the starboard tank via the genset fuel return line. There is no danger of pulling air into the fuel supply of either the main or genset.

Photo #1 shows the equipment panel located just forward of the water heater in the “tank room” under the saloon. The valve at lower right controls the supply. Diesel is pulled thru the Racor by the Walbro FRA-4 pump and then passed to the Reverso distribution manifold. Pump capacity is 32gph. There is a shut off valve atop the Reverso manifold for each return line.

Photo #2 shows the supply take off from the 5/8” ID crossover hose and the return to the starboard tank via a tee into the 5/16” genset fuel return line. Closing the left valve will pull fuel from the starboard tank. Closing the right valve will pull fuel from the port tank. Leaving both valves open allows the crossover line to function normally with a constriction of the crossover from 5/8” down to 1/2”. Closing either valve disables the crossover function during refueling.

Photo #3 shows the fuel return to the portside tank via a spare 1/2” port provided by the factory.

Fuel can be polished or transferred either underway or at the dock. I would recommend that the starboard tank polishing function not be used while the genset is running. I don’t believe there is a problem with returning fuel from the polisher to the genset return line while the genset is running but increasing the diameter of the 5/16” return hose to 3/8” from the return tee to the starboard tank (same as return from polisher to port tank) should eliminate any concern.

The pump makes audible clicks when operating so there should be no danger of forgetting to shut it off before leaving the boat. Power is supplied through a SPST toggle switch from the terminal block providing 12V to the middle bilge pump. It is visible just to the right and behind the panel in photo #1. A metal drip cup modification for the Racor is on order.