Three years ago I bought an old Hobie 16 just because it looked like fun. I had never been on a sailboat in my life. I used all the information I could find (mostly on the net)to fix it up and get it ready to sail. There are few catamarans in this area of Ohio, so I didn't know of anyone to ask for help with sailing. One April afternoon my wife and I took the boat out in high winds for our maiden sail. (photo below)I had read enough information about sailing to realize that I could reef the main sail (lower the sail area by 20% or so) and leave the jib in the van. We didn't do too bad and for the first 45 minutes our only mishap was getting blown backwards into a stump that was hard to get released from. When we were about ready to call it a day, I turned the boat downwind during a gust of wind and were promptly flipped over. We righted the boat fairly quickly and returned back to the dock. Our next outing went better and we've been improving ever since.
If you can get help when you first sail, that would be great, especially if you are on the ocean or large body of water. As for a boat, in order to haul 4 or 5 people around you would probable need a 20' boat, which is hardly a beginner boat. I now have a Prindle 18, which is a nice, forgiving recreational boat, but I don't think it would handle more than 3 people with out some difficulties. You might want to purchase a 16' Hobie and sail it a season or so before you decide on what you want in the future. If you've got the bucks, a Hobie Getaway would be a great boat to learn on and it would haul more than a Hobie 16.
Good luck,
Jack Hoying
Fort Loramie, Ohio