Do they flush with fresh water?
Salt water plugs up the drains from conventional urinals.
Nothing like pee on the toilet seat
The description I recall from hearing about my dad’s stint aboard an aircraft carrier in Korea was that it was just a long, saltwater trough with seats suspended over some sections of it, with the waste just sent right back into the ocean. They used to play pranks like lighting a wad of toilet paper on fire atop a turd for the sheer amusement of hearing the guys downstream yelling as their butts and other rhyming appendages got singed one by one as it floated on down the line and eventually out to sea.
Nuclear powered vessels have loads of fresh water. They make it.
The old salt water commodes are gone, replaced by a modern vacuum system that gets clogged if someone as much as tries to flush a chem wipe down the toilet and doesn't work very well for urinals.
People are going to try to make this a gender issue. It's not. Smaller navy ships have been using this system for a while now.
Salt water flushing disappeared with flash distillers
Do they include bidets for Senator McCain?
On the USS California (CGN 36) we had a “urinal” in the middle of a work space in engineering. Not sure if it really was used as purposed, but it did make a great spittoon.