Mainship 390 2000 fuel transfer

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Mainshiptom

Veteran Member
Joined
Apr 29, 2018
Messages
79
Location
United Kingdom
Vessel Name
Naphy III
Vessel Make
Mainship 350/390
I have just found out after having the boat for a year that my tanks have the facility to transfer diesel from one tank to the other.

so my starboard is half full and my port is full, but how do IO do do that?

any instructions on steps would be welcome..

Thanks in advance

Tom
 
There should be a passive cross-over that does it automatically.
 
fuel pump

There should be a passive cross-over that does it automatically.

There is an electric pump which I have switched on and more controls on flybridge

just not sure how to operate..
 
Doing the transfer using an electric pump has some uses, but one must be very careful not to overfill the receiving tank. Depending on the pump, huge amounts of fuel could be quickly ejected from the vent line. If you simply want the tanks to be even, you should also investigate whether there is a passive "automatic" equalizer line.


Ken
 
I'm not sure if it is the same on the 390, but on our 400 which has a passive crossover line, if one tank is a good bit fuller than the other the boat lists to that side and the fuel won't transfer to the (more) empty tank. Just a heads up. You may have to temporarily weight one side of the boat.
 
Uneven tanks

Doing the transfer using an electric pump has some uses, but one must be very careful not to overfill the receiving tank. Depending on the pump, huge amounts of fuel could be quickly ejected from the vent line. If you simply want the tanks to be even, you should also investigate whether there is a passive "automatic" equalizer line.


Ken

Ken

There seems to be a Passive system in place too since every day some fuel is moving over but the boat is still listing to one side and it would be nice to find out how to use the electric option since it has been installed as an option on the flybridge helm as part of the Mainship control panel.

Maybe there is a fuse somewhere?
 
I hope it has a fuse or breaker. If it was installed by the factory it should. Have you been able to physically locate the pump? If not, perhaps have somebody turn it on while you're near the tanks. If its strictly a transfer pump, it could be a bi-directional pump (which would mean either a 3 position switch(hopefully) or 2 different switches) or it could have a few valves that need to be manipulated to chose fuel flow direction. Unfortunately, I am not familiar enough with that boat to help you with the exact configuration.

Ken
 
Tansfer fuel pump running but

OK , found the switch its connected to one of the lights switch on main panel(Silly)

Pump running for 10 minutes but can not see any difference?

Maybe impeller in pump has perished, investigating.
 
OK , found the switch its connected to one of the lights switch on main panel(Silly)

That is an after-market installation. I would be surprised if any professional or the factory would have jumped off of a light switch.

My guess is the PO was trying to solve an issue with tank balancing to begin with.
 
I have to wonder if the breaker/fuse and wire gauge is sufficient for for the amp draw of the pump and the distance from the battery, to panel, to switch to pump and the return trip of the ground.
 

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