A pipe clamp 10 for repairing an underwater pipe. The pipe clamp 10 comprises a plurality of part-cylindrical portions 12,14,16 hinged together along a hinge axis or axes 27 along adjacent longitudinal edges 17,18. Two or the longitudinal edges 20,21 of the part-cylindrical portions are free. The part-cylindrical portions 12,14,16 are movable about the hinge axis or axes 27 towards and away from one another between an open position in which the free longitudinal edges 20,21 are spaced apart and the clamp 10 can be placed around a pipe and a closed position in which, in use, the free longitudinal edges 20,21 of the part-cylindrical portions 12,14,16 are brought together around the pipe. Fastening means are provided for holding the free edges 20,21 of the part-cylindrical portions 12,14,16 together, such that, in use, the clamp 10 is held to the pipe.