Another Question About Tri Hulls

Doug Lord said--- "a planing ama may work on small high speed trimarans"

A case in point was the Piver Frolic. It was very fast.
The floats were of box section and if you took away the sides and deck you were left with a pair of water skis.
Since the floats were lightly loaded it worked very well at that size.

 

There were some AYRS guys who put retractable foils on a day sailing catamaran, a long time ago. The inverted T foils were not particularly large, so only worked at a high speed, which was fine with them since they felt no foil was more "efficient" at lower speed. These were not submerged very deeply and it was noted that they ventilated at a certain speed. There was some wishfull thinking that they could increase the size a little, and when they ventilated they could be given more of an angle of attack and act as a ski or planing surface. No report that I saw ever said this was proven to work.

Marc

 

Yes there was a guy who took a 30 ft Piver Nimble and fitted hinged retracting ladder foils to either side and at the stern. He sailed it across an ocean (I think the Atlantic). He found that the conditions had to be just right for the foils to be effective, and its crossing time was nothing special as a result. It was all written up in an issue of the AYRS.

 

That was David Keiper in Willwaw but although it looked Piver-like, was his own design with smaller floats; here is Williwaw (left photograph) when he crossed the Pacific to Auckland. I went aboard and had a very interesting talk to him.