Dear Martha, first of all, where are you located? I am in Madison, WI, and I have an M-17, if you are somewhere near I'd be glad to take you along for a sail someday. I did the same kind of research that you are interested in and the unanimous opinion was that 4 people do not fit in an M-15, the cockpit is too small. I was interested in sailing myself, my wife, and two young boys and everyone on the list agreed that it will be too cramped. In an M-17 4 people fit very comfortably for a day sail. Secondly I don't know about storing outside: around Madison (within a 30 mile radius) there are many farmers which offer in the winter their barns to store boats, sports cars, etc. This is a well established business and it's easy to find such people on craigslist. The cost is very reasonable, around $150 for the whole winter, and the boat sits inside. With my M-17 the only thing I do before putting her in storage is drain the water tank. Good luck, Andrei.