
Posts: 3514
Location: Elk River, Minnesota | Hiya,
you are right on the edge of where it can do some good. A steel prop will usually be made in a manner to have thinner blades, thus it will cut the water better than a standard aluminum. There is usually something to be gained, not only in durability but in handling as well. In most cases you can raise your motor a couple of holes to gain some rpms back.
in your case with the 75 tiller (four stroke?) , I would highly suggest the ballistic propeller. It will give you close to the same RPMs as your aluminum (at least that was the case on my yamaha 90 I had). If this is a 4 stroke, you are getting good numbers on that boat already. with my 90, it was a 38mph boat until I did a few tweaks to the motor with the help of hydrotec marine.
the ballistic is highly cupped, which is what allows you to move the motor up and not lose too much handling. I loved it on my 90hp.
my suggestion would be to find one to try in the same pitch as your current aluminum and see how it performs. I would not be surprised if you saw a couple mph increase in speed. And...if you can then move the motor up a notch or two, you might even get a 40mph boat. THAT would be a great performer out of a 75.
Steve |