Hi. I can't work out what this guy is. Big wires are to the battery switch I think (bit of a
mess back here) and the small wires directly to the battery. Could it be some sort of terminal post?

Could be a terminal post.
However, the big wires with those endings are for engine cranking/starting. The little ones might be to a push button, and here will be a relay to the starter motor.
Otherwise, an exciter circuit to the alternator for the little wires.

It looks like a starter motor solenoid/ switch/relay to me.

Same could be used for other big amp draws like an electric windlass

For sure, Woko.

Gary

Excellent thanks for that. I'll follow the wires to see if it's for my engine starter or for the windlass. Great thanks.

Select to expand quote

jbarnes85 said..
Excellent thanks for that. I'll follow the wires to see if it's for my engine starter or for the windlass. Great thanks.

Or disconnect a wire and you will soon find out what its for