haven't tried it, but have seen one on a 3 man outrigger canoe. the kite lifted the canoe most of the way out of the water on the jibes. they told me it flipped once and took off without them. no fun.
they could get upwind alittle even without boards and with round bottoms. once airborne the platform isn't very stable. if you manage to stay with it after a capsize, rightng shouldn't be a problem. the mast doesn't really help you right a turtled cat. the righting line does.