Strain monitor

The invention relates to a strain monitor to measure the structural integrity of a submerged structure e.g. offshore oil platform. A strain monitor (1) attaches to part of a submerged structure (100) and comprises a main body (5) which is of concave shape and having an attachment assembly which is arranged to secure the strain monitor to the submerged structure. A plurality of strain gauge assemblies (3 in figure 3), carried by the main body, are arranged in a spaced apart relationship with each strain gauge assembly comprising a strain gauge attached to a carrier (6 in figure 5). The strain gauge assembly is arranged to selectively adopt a stowed condition while being lowered and moved into position, then when in the correct position it is able to be deployed in a controlled way so it attaches to the submerged structure (e.g. brace pipe) by partially surrounding it. The assembly includes a data processing, storage and communication module. The apparatus may be attached to the submerged structure using an ROV.