Prop Problem

[johnfpo]

Hi I got a 30ft catamaran 4 ton <br />I recently put a 1994/1995 70hp Yamaha 2 stroke<br />on it <br />I can only get 3500 rpm and 7.5 knots<br />Would a different prop make any improvement?<br />I do not know what prop is on engine..there are no markings..I was previously on a fast boat (25 knots.Any advice

 

[JB]

Re: Prop Problem

You need a high thrust prop for that application, John.<br /><br />Find out what pitch you have and get one with about 4" less pitch.<br /><br />Good luck.