greenwire on fuel tank near sending unit

[spareparts]

it should be hooked to the engine bolt, and the gar board plug(run a machine screw thru one of the holes for the plug instead of a wood screw, use a nut on the inside of the hull for the green wire to hook to it), and anything else that touches salt should be connected to green. They tell you the ground bonding wire is a separate circuit than the battery ground, but they usually end up connected at some point. If its hooked to the engine , you shouldn't have to hook it to the battery ground

[SkunkBoat]

Your motor is connected to the battery. The Black wire is connected to the negative terminal. So you can connect the tank ground to the negative terminlal or any place that is also connected to the negative terminal.
Usually the fuel fill and vent have a ground wire too.

As for corrosion of the tank, make sure you seal the hatch with silicone so water doesn't get in. If you remove the foam & tank you'll see that it is in an Undrained compartment. Any salt water that gets in stays there forever. Thats what corrodes tanks.

[pancake]

yes they do have the original wire still connected.