Catamaran in Grand Turk?

[cruisinRN]

Wondering if there is a tour operator that offers a catamaran, snorkel excursion in Grand Turk? We have 7 in our party and 2 of our family members are seniors, and not as athletic. We would like to do a snorkel excursion but if the only option is via boat, my concern is that climbing in and out of the water via a ladder in the water might be challenging for them. They have both said they will just come along and watch but that seems like a waste of $ if they are not going to snorkel...and at least a catamaran is comfortable and more of an experience overall if you know what I mean.

Thanks for any help.