I came across this very interesting bit of information on the Elf catamaran. It says with a 6 HP outboard, 6 kts can be achieved and you can get 10 kts with a 15 hp. If you want to waterski, use a 35 Hp engine. I wonder if there are any hull design secrets that allow this particular design to get the fantastic performance under power.
I had just sold off my 8Hp Suzuki long shaft engine that used to power my Strider 24 and was eyeing for a Yamaha 8 Hp but they do not produce anymore 2 strokes 8 Hp longshafts. I might just settle for a 4 stroke Suzuki 6Hp as it is light (27kg). Wonder if any Strider owner has a 6 Hp and the max speed that can be achieved.