Abstract: The invention relates to a device for repairing and fitting heat insulation capabilities of the external cladding of clad members such as tubular lines, connection members and other clad members, positioned on the seabed, said device consisting of a casing comprising attachment and/or tightening means, suitable for being mounted on said clad members, characterised in that the device comprises, inside the casing thereof, a gel type elastomer heat insulation compound, in the form of a solid or perforated lining/mat, rigidly connected to said casing and compressed by tightening on the clad member during the fitting thereof.