A barge-carrying vessel (1) comprises an afterpart (2),a forepart (3), and a beam system (4) connecting said afterpart to said forepart, said beam system having fastening means (14) for barges (B), connectible to said beam system and said fore- and afterparts, such that the outwardly facing shell plating portions of the barges substantially coincide with the adjacent shell plating portions (8) of the vessel. The novel matter of the invention resides in that said beam system (4) incorporates a beam (5) of lattice construction, one end of said beam being supported substantially stationary by supporting means (7) on the afterpart (2), and in that the forepart (3) has beam supporting means (9) adapted to permit relative displacement such that said fore- and afterparts (3, 2) can be moved towards and away from one another. If required, barges (C) can be loaded on top of said beam (5) via ramps (36) and sliding members (34) at the deepest trimmed beam end (at the forepart).