Some are both, the Truth does one day trips but is a liveaboard. What I love about that boat is the heat from the engine and compressor is vented thru the shower/changing room so after diving in that chilly Pacific water you can warm back up and hang your wetsuit in there to dry :)
All dive boats need rinse tanks for mask and camera gear. At least a hose for a quick shower. Dry storage area. Shade. Water to drink, a cooler for what you brought along, a sign saying if you didn’t put in the cooler it’s not yours!