I guess you knew about these, I just saw this picture on a small boats page in Facebook, it seems that this particular bracket allows you to turn your outboard a full 360 degrees
it looks good !
original transom bracket
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
Re: original transom bracket
They are a 1970s accessory, not made by seagull. It's called a "Rotogull" They do have a tendency to seize up I've heard.