Abstract: A locking system for the type outboard motor assembly to a boat transom that is held by bolting through a motor mounting plate and through the boat transom includes: (a) the bolting being by round headed bolts with preferably non-circular section necks to prevent gripping the head and turning the bolts, (b) nuts on the forward face of the transom securing the bolts, (c) shielded perforate threaded collars on the free ends of the bolts and jamming tightly against the nuts, (d) a headed perforate stud through the perforations in the shielded perforate threaded collars to prevent them from being turned and (e) a padlock through one or more perforations in the free end of the headed perforate stud outboard the adjacent shielded perforate threaded collars to pervent unauthorized removal of the headed perforate stud.