[Minnewaska]

Are you going to have the boat a while? If so, get the right tool for the job. In your case, that would seem to be a motor with a longer shaft.

Btw, your mounting bracket could have been installed to the transom before other parts of the interior cockpit were fitted. If the interior is now inaccessible, its not impossible to fashion a system that secures from the outside. However, I agree that its not your best choice, only less expensive.