Abstract: A shifting tween deck structure for the holds of cargo vessels including a plurality of parallel beams movably supported between pairs of rails adjustably secured at the sides of the cargo hold. The beams span the hold and are individually movable on the rails to a central position below a cargo hatch to receive omnipallets of cargo which are supported in the hold between two adjacent beams. At least some of the omnipallets are movable on the beams, and the loaded pairs of beams are shiftable to the side of the hold. The unloaded beams are optionally shiftable to the sides of the cargo hold to convert the hold for dry bulk cargo or the beams can be removed and stowed on deck.