Abstract: Apparatus for remotely placing and welding a patch over an underwater breach in the hull of a ship. The apparatus is lowered into position over the side of the ship by a winch and cable, then held against the ship's hull by electromagnets. The apparatus has a generally streamlined frame containing a chamber within which a patch plate is carried. Wheels are disposed on the frame to permit the frame to be driven along the hull and positioned over the breach. The patch plate is then moved into position against the hull and welded into place. Operation of the apparatus is viewed through video cameras and is remotely controlled by an operator on board the ship.