Dear Bob et al., On Kenlanu we had just such a plug out in the cockpit intended for the old autopilot. I looked long and hard for a matching male plug and found none so if you find one that matches please let me know. My solution was and is butt ugly but effective. I got a couple of 3/16 brass bolts ( if my memory serves), cut off the heads, ground them (with a file and an electric drill) to a nice taper to seat well in the holes, and drilled holes in the other ends so I could solder the wires in. When all was set I then plugged them in (power off) through a bit of plastic bag and then molded some quick-dry 4200 around the pins to create a plug. Eventually I hit on using a 1" wide strip of yogurt container tightened up with a hose clamp to give a bit better shape to what is still a very ugly plug. But we use it for our cockpit/anchor light so who's looking at the plug in the dark!
Again, if you find a good supply for the male plugs, please let us know!
PSC 37, Kenlanu