I just bought a 1979 Grady-White 18' Adventurer. The original motor, a 175hp Johnson, needs to be replaced. I think 175hp may be overkill on a 18' boat and I am considering a 115hp. The original owner said when the motor was strong it could go 60mph. The boat will primarily be used for just cruising, with a little fishing and skiing thrown in. <br /><br />Any opinions on what size motor is adequate?<br /><br />Thanks