Stepping and un-stepping of a sailboat mast, of the un-stayed type that is supported only by a receptacle configured in the sailboat structure, are facilitated by a hinged core that is easily retrofitted into the foot of the mast. The core includes a two-part locking hinge that, when the mast is elevated up out of the receptacle in process of stepping or un-stepping, serves to keep the mast upright with its base held aligned in location above the receptacle. Then the hinge, located at the foot of the mast, can be unlocked to allow the mast to be tilted down to any desired angle, where it can be easily removed. The system enables one crewmember to easily step or un-step the mast manually on sailboats up to about 30 feet in length, optionally assisted by a small lifting winch that can be rigged on board.