Abstract: A magnetic ship hull patch (10) for temporarily sealing a breach in a ship hull (14) or other vessel wall by use of electromagnetivity. The magnetic ship hull patch (10) includes a rigid plate member (20) configured to substantially conform to the outer surface of the ship hull (12). A plurality of reinforcing members (24) is provided for strengthening the rigid member (20). At least one electrically operated magnet (30) is provided for selectively securing the rigid member (20) to the ship hull (24). At least one power cord (36) is provided for communication between a power source and each of the electrically operated magnets (30). A cushion (44) is provided for conforming a surface of the rigid member (30) to the shape of the ship hull (12) at the subject location of a breach (14). A seal (50) is provided for sealably engaging the magnetic ship hull patch (10) with the ship hull (12). A support (56) may be provided for the storage and simplified transport of the magnetic ship hull patch (10).