1967 Evinrude 100 turning trim

[John Freed]

I have a 1967 Evinrude 100 HP on a 19 Ft. Thompson. As is often the case, there is a significant right turning tendancy. There doesn't appear to be any trim adjustment on the engine. Was there an aftermarket trim tab to solve this problem? Would hull trim tabs help? I have the verticle trim fairly perpendicular. Would changing this to be more bow down or up affect the right turning tendancy?
Thanks,
John Freed