Almost 15 knots and not flying a hull? He had to have been pinching too much. (or in a different wind) Most any catamaran talked about on this forum will fly a hull in 15 knots if the traveller is centered and the main sheet is tight..........

Keep it simple before going to all that technical stuff. Improper diamond wire tension / spreader rake usually affects performance in a different way. Like if the prebend is say too loose the boat won't drive forward when hit by a gust.......it will just fly a hull and go really slow.



Tom