Miami Herald (may have a paywall) recently had an article about nascent boat sharing / P2p Boat Renting sprouting up.
Making waves in ‘the sharing economy’: Peer-to-peer boat rental companies arrive in South Florida - Business Monday - MiamiHerald.com
I do think this is the future...along with outfits like Sailtime. The cost of boats has just kept going up and up and up, with no end in sight. So like real estate where house sharing and airbnb came up, the future will have a significant amount of boatsharing.