No, no, no. "Shirley you're joking" [Airplane]
There's no "neutral" in a DC system, there's positive and ground. Neutral refers to a line in AC systems.
All you are going to do is make one battery very well charged while the others aren't, and the resulting difference is just going to screw up your system. Disconnect it now before something blows out or blows up. If you have a 36V battery bank, that sounds like an aircraft not a conventional BOAT.
You need a nominal 36-volt solar
panel, or three 12volt panels
in series, and an MPPT
controller that can handle 36 volts, to charge the 36-volt house bank, if that's what you really have.
I'd strongly suggest some heavy reading or calling in an electrician before something exciting happens.