We went on the catamaran sail and snorkel in Roatan, thru Carnival, and had a great time. It is not a booze cruise at all, there is one free rum punch available after snorkeling but after the one you have to pay for alcohol so no one really gets intoxicated. The crew on the catamaran is great and very entertaining, there were several people who didn't snorkel and they still had a great time enjoying the view and sun.
There are a couple beach party type excursions where they take you to a nice beach basically with drinks and snorkeling. Lots of the families on board went on those and had a nice time.
If you have anyone who snorkels Roatan has really excellent snorkeling and diving, the coral is still all alive since it isn't a major tourist destination yet.