86' Hatteras electrical gremlins

You have a source for 24VAC LEDS?
The pins up, G4 replacements we tried started failing in days.

AC no, but then again I've never ever seen 24v ac g 4 lightbulbs either, just 12 volt ac. Hatteras uses a AC to 24v DC converter, usually Newmar. Reason being Hatteras uses very few batteries for their boats, so they go with the AC to DC converters so you don't have the lights flickering and stuff like that when there are heavy DC loads.

I've had good luck with the Scandvik g4 LEDs, but make sure the circuit board isn't touching the housing anywhere. I replaced 65 of them on the 62' Sunseeker about 8 months ago and haven't had an issue with any of them. Just got off of a delivery of a 2006 64' Hatteras MY that had the pins up Scandviks throughout the entire boat and no issues with any of them since they were installed.

Ah, but there's the rub,,,
This 2009 Hat uses 24Vdc in the closets and rope lights. That is O K and converting over to LEDS.
All other over head G4 lights are 24V AC from those transformers. So, we can not Just put the LED bulbs in and be done with it.

Our new best friends at DRSA are sending a kit for us to experiment with. We should have a plan together next week,

Might be easiest to just change the transformers to AC to DC converters.

One of the toys coming in for us to experiment with is a dimable DCv power supply (LED Driver).

You got that rite. We added a bank of 31s for the gen-sets.

Get the constant current bulbs and dimmers from marinebeam.com for best performance and longest life. I screwed around with cheap off the shelf LEDs , for converted 12vAC as well as DC, and once i found these all was well. The guy understands Hatteras and boats in general, good knowledge source.