When you install the motor by tightening the nuts that hold the motor mount to the bulkhead, have an ammeter connected. When the current draw is the least, the shaft is dead straight. You may have to loosen some and tighen another to get it dead straight. This is because its pretty hard to actually install the rear bulkhead perfectly vertical in the hull. And dont overtighten, you can pull the embeded bolts out of the bulkhead. If you have any questions as you build, just ask :)