A sleeve and collar system for an oar includes a sleeve configured to couple to a shaft portion of the oar. The sleeve includes an outer surface. The system also includes a wear collar configured to couple around the sleeve at each of a plurality of longitudinal positions along the sleeve. The wear collar is configured to bear substantially all direct contact from an oarlock during a rowing stroke of the oar. A radially inner surface of the wear collar is shaped to be complementary to at least a portion of the sleeve outer surface, such that the wear collar inner surface and the sleeve outer surface cooperate to maintain the wear collar in a predetermined orientation about a longitudinal axis of the sleeve at each of the plurality of longitudinal positions.