Yes; check with Captain Van Rooyen from Interlinesail. They have 4 yachts so could do a tandem sail/with raft up/for 18 people. Most yachts/day sails in the area can only take up to 6 passengers max, due to some kind of law/restriciton. Your best bet is to take 3 boats, sail together, and raft up for the lunch/snorkel. I know they have a website, www.interlinesail.com , but would suggest you call direct to 704-987-5003 to check availability and rates. Hope this helps?