I contacted KeelGuard and Hambys.....Keel Guard replyed back.....here is what they said about putting on aluminum boats. I think it will work on mine.

Aluminum is one of the best surfaces to bond to. The concern is more the
design of the hull. If your boat has the reinforced rib that protrudes off
the hull an inch or so, we do not recommend installing a keel protector. Air
can get trapped in the corner seams and leave too little flat area on the
hull to achieve a strong bond. Many aluminum boats have the raised rib and
are not the best for bonding external material. These "ribs" or reinforced
areas are designed as a built-in keel protector from the manufacturer.

You could still attempt to use the KeelGuard on your boat with the raised
rib, but long term success cannot be guaranteed. It could work for a season
or two or maybe longer but it might fail within the first year. Some
customers have been creative and taken a utility knife and split the
KeelGuard down the center groove and then installed the protector on each
side of the rib where the aluminum is not reinforced.

Unfortunately, we are unaware of any existing product that conforms
specifically to this type of hull. Again, these raised ribs are meant to be
a reinforcement to provide extra protection.

If your boat has a hull that is welded or formed or even has a riveted
plate, then the KeelGuard could work very well as long as the lip/edge of
the keel protector does not come into play with edge of the plate or rivets.

Please feel free to call us at (800) 292-9835 if you would like to discuss
your application in more detail.

Thank you for your interest