I recently replaced the key switch in probably an identical panel (in a 19980 Niagara 35 with Volvo MDC11 engine). My solution was a $14 toggle switch. This way I don’t need to worry about those flimsy Volvo keys self destructing or getting lost. As the batteries and main switch are down below, when they are shut off and the cabin locked, the engine is as good as locked.
For those who might remember my post to this page some time ago, I did the same thing to my Nonsuch 26 (Westerbeke 22 panel). In that case, it was because the spring in the key switch failed, leaving the starter motor running after the engine started running. Damage was significant (burned heavy wires right back to the main switch and melted the switch housing, lots of heavy wire to replace, lots of smoke to eradicate…).
I have never worried about losing or bending an ignition key since.
Greg Silver
Misty Cat, 26C #121
Also No Rush, Niagara 35 #86
St. Peter’s, Cape Breton