Trilogy has a couple of big sailing cats or another less dive-focused but stabler option could be Pride of Maui, it's a big powered cat that also offers a more expensive dive option to Moolokini. It's also more of a snorkel boat - there's even a waterslide. And they do a bbq lunch. Nice thing is they moor way up inside the crater so it's pretty calm - the dive is straight out back toward Maui. Look for whitetips in the sand nearby.Also they drop stairs into the water so entries couldn't be easier.
I can't remember the name but there's another big sail cat that sometimes beaches near the resorts in south Maui - IIRC they also offer diving.
The biggest, likely most stable non-cat on Maui is probably one of the Lahaina Divers 65' Newton dive boats - I believe they have stabilizers on the hull. Extended Horizons or Hawaii Rafting use much smaller boats - we watched the HR divers get thrown around pretty good at the Cathedrals once - it's a hard-hulled zodiac.
All the Molokini (south Maui) boats leave from the boat ramp so they're smaller. They actually go early in the morning since coming back can be rough when the tradewinds pickup.Probably - but I'm not sure - the most stable is B&B Scuba's - it looks like an older flat ex-military boat.
Thought about shore diving? Both Maui Dreams Dive Co. or Shaka Divers are guided options in South Maui - there's some decent diving off some of the beaches nearby.. In West Maui Tiny Bubbles in Ka'anapali is an option also. I think Extended Horizons also guides in the afternoons. They're near Mala Wharf - arguably the best shore dive there but the entry requires going over some rocks and picking your way thru shallow coral.
Black Rock is a pretty famous shore dive - easy entry off the beach. We also liked Old Airport but we had scooters to get out to the farther - and IMO better - reef. We liked Wailea Beach in South Maui - all the good stuff is off the south point. My friend said Polo Beach nearby is even better.
On Hawaii the only dive operation I'm aware of with a cat is Kona Diving Company - recommended.
As NorcalDM mentioned there's a lot of shore diving options on both islands. Maui entries are often off sandy beaches,. some of the Kona entries are rougher as you have to pick your way thru the lava. Some of the Kona sites are also fairly long carries from the parking to the water - only 1-2 of the Maui entries are longer walks.
Old but still fairly accurate - nice thing is the entry pictures.
Scuba Shore Diving Region: Hawaiian Islands
