The invention relates to a method for securing horizontally loaded cargo units on a vessel, in which method the cargo units (13) are handled and secured for transporting the cargo units (13) on the vessel. The cargo unit (13) is secured to the vessel and/or to an adjacent cargo unit (13) by means of securing elements extending in the longitudinal direction of the cargo unit such that securing parts (11, 12) of the securing element (10) fixed to a bulkhead (15) of the vessel and to the cargo unit or to adjacent cargo units form an interlocking coupling, whereby the cargo unit (13) that is secured remains in place in the securing position. The invention also relates to a device for securing horizontally loaded cargo units on a vessel, which device is used for securing the cargo units (13) for transport on the vessel. The device is formed as a securing element (10) extending in the longitudinal direction of the cargo unit, which securing element comprises securing parts (11, 12) fixed to adjacent cargo units or to a cargo unit and a bulkhead (15) of the vessel adjacent to the cargo unit, which securing parts form an interlocking coupling such that the cargo unit (13) that is secured remains in place in the securing position.