Strakes on both sides of each tube. Top speed GPS is about 43 MPH, not really sure about the prop size, it came on the motor from the dealer, I am sure it is nothing special.
I have the 22slx twin tube with lifting strakes and the 115 Yamaha. I run a Yamaha 13.5x15 prop. With 1/2 tank of gas and one person on board I get 35 mph on the GPS.
