Liability in collisions between vessels : hearings before the Merchant Marine and Fisheries Subcommittee of the Committee on Commerce, United States Senate, Eighty-seventh Congress, second session, on S. 2313, to unify apportionment of liability in cases of collision between vessels, and related casualties; and S. 2314, to limit the liability of shipowners, and for other purposes, March 1 and 2, 1962