Hatteras retrofit cost and ideas

You can find people to work on the old 2 stroke DD's all over the world. The US military spread them all over the place and many are in service in far away places as generators, truck engines, heavy equipment, etc. Parts can still be had for them, although there might be a little lead time for some things. The old 2 strokes are more efficient at slow speeds (<1000rpms) than even modern 4 strokes, but are a little less efficient above that. I like the 71 series, and although a bit crude......oil leaks, can smoke on startup, can load up after a lot of slow speed running, they're easy to fix and run and maintain. The 92' series I'm not as big a fan of as they don't generally enjoy nearly the same service life as the 71's. It's FAR cheaper to rebuild them than replace. The thing with D.D's is you never really can have a clean engine room, clean bilges....if you stay after it you can keep everything relatively clean, but not clean clean.

However replacing has good options too if willing to spend 3x the money. More HP to weight ratio, cleaner running, electronic controls, warranty, quieter, faster boat, more fuel efficient at cruise etc.

Everyone stayed with 32 volts until that era, Bertram even later and others. It's 25% more efficient than 24 volts. If an item uses 15 amps at 24 volts it will use 12.5amps at 32. Battery chargers weren't that large back then, most items were a bit more in-efficient, etc. etc. It's quite a bit to change to 24 volts. Depending on wire size you might have to re-wire the entire boat to switch to 24 volts, usually not on a Hatteras. Rewiring a motor yacht that size is a major undertaking both in cost and work involved. You can get around that by also converting to more efficient systems that use less electricity (toilets, pumps, LED lightbulbs etc. etc.) Engine starters, alternators have to be converted to 24 volts. Every DC system, F.W. pump, blowers, bilge pumps, toilet pumps, battery charger, battery bank re-configured, light bulbs, and on and on, it can get quite lengthy and expensive. If it's a working 32 volt system then keep it, as other people have said you can find the parts and just carry lots of spares on board and replace as needed. Some things will get around having to swap, like some LED light bulbs are rated 12-36 volts so as long as they're the right footprint convert to LED's.

i converted my 1972 58 hatteras yachtfish to 12 volt about 8 years ago and have not had one problem with the wiring being undersized.
it was a no brainer for me....when repowered the po used 12 volt john deeres, a 12 volt generator and 2 of the heads were replaced with 12 volt. all i had left was bilge pumps lights windlass, and blowers

I remember the wiring on the 1979 58' YF I ran for many years to be pretty large gauge for the loads they were carrying. I would think converting to 24 volts would be fine, but 12 volts would start making the wiring size simply too small gauge for many items. It's possible the heads use a lot less amperage than the galley maids, but who knows. The wiring on a set of 24 volt vacuuflush pumps on a boat I was just working on is 14 gauge, I replaced both heads with Raritan Marine Elegance which use 10-12 amps I think.

i didn't change any of the wires,didn't change any panels, only some of the breakers, and didn't change any of the fixtures, just the bulbs in them.

my insurance company know about the change and didn't have a problem with it. it was noted in my purchase survey that the system was being upgraded to 12 volt. upgraded is the word the surveyor used. as for a purchasing surveyor, i'm not worried about that, i have no intentions to sell her, she is the perfect boat for us.

If the fuse/breaker size is correct for the wire gauge, then, in theory, the fuse /breaker will pop before you cook a wire.
Still, be sure your insurance is up to date and the fire extinguishers are current !

I have never heard of a DC Negative being yellow. Whose rules cover that one?