Sorry, I was reacting the the number of times I was approached with the
question "Why can't I plug this in here?" or "This almost fits. What is
wrong?" Lots of years as the facility guy will do that to you.

Heh, no worries.

Trust me, I understand the shore power connection issue. My boat has no
installed shore power and no need, but my aged little motorhome has a
locker full of adapters and connector and silly little cables (some
fabricated late at night over the last 30+ years) and that doesn't even
have to be locking or retained or sealed.

Thus my question. It's not so much a matter of that I "need" to create the
adapters as I'm looking to get a bit more familiar with what can, can't,
should, shouldn't be done with them. I keep my volt meter on board and use
it when making connections to sketchy setups. It's not that often and most
here on the Bay seem to do a reasonably good job of using normal setups.
But knowing ahead of time stands to save me (some of) the hassles of those
late night fabrication efforts.