A watercraft lifting system includes a bunk rail assembly, an intermediate frame assembly, a base assembly and a ground support assembly. The bunk rail assembly includes a bunk rail coupled to a load distribution member. The load distribution member is received by the bunk rail such that the bunk rail may rotate by at least a limited amount relative to the load distribution member. The bunk rail may slideably receive a bunk cushion and form a channel therewith for sandwiching a rigid structural member (e.g., a board). The watercraft lifting system may also include contoured clamps that cooperate to distribute and transfer load between frame members. In one embodiment, the contoured clamps include parabolically-shaped inner surfaces.