An alternative to Sandals is Sunset Beach Resort, especially if you have children. That is what we did while in MoBay. It, too, is an all inclusive. I don't recall whether or not they had catamarans, but the cost is only $40 pp for adults. It is not one of the excursions, but taxi cost was only $2 each for 5 of us, each way. The resort is very near the port. There are pictures in the gallery. We had a great time. I haven't been to Sandals, but we thoroughly enjoyed our time here.
Oh, yeah! The reason there weren't any people in the pictures is because the resort was closed to overnite guests due to remodeling. When they are up and running, they limit the number of day guests to 100 (I think). I contacted them before our cruise. Their contact is listed on their website.