to fig1 there is shown an item of underwater equipment 2 which is surrounded by thermal insulation 3 as particularly described with reference to fig3 4 6 and 8 where the thermal insulation 3 is totally enclosed within the shroud around its external surfaces 20 around its internal surfaces 23 between the equipment 2 and thermal insulation 3 and its end surfaces 21 the section of shroud 1 between the equipment 2 and the thermal insulation 3 may be completed before or as a consequence of its assembly onto the equipment 2 the formation of the section of shroud 1 between the equipment 2 after its assembly onto the equipment 2 thus extending the entire length of the shroud the formation of the inner part of the shroud in this way may at the same time bond it into place onto the apparatus 2 referring to fig1 there is shown an item of underwater equipment 2 which is surrounded by thermal insulation 3 as particularly described with reference to fig1 where the thermal insulation 3 comprises a plurality of discrete lengths between which are circumferential bulkheads 5 the bulkheads may be either be preformed and positioned between the thermal insulation 3 or formed when casting the enclosing shroud such that they become an integral part of the shroud referring to.