A method of making a multitubular sheath comprising providing a porous multitubular fabric impregnated with thermoplastic or deformable polymer, continuously feeding the fabric onto an array of parallel metal rods, one tube to each rod, the rods having straight sizing portions, while holding the rods in a fixed position, the rods having substantially the same cross sectional area over the whole of their length, the fabric at least immediately prior to the sizing portions being substantially at ambient temperature, heating the fabric on the sizing portions so as to permit the fabric to conform to the rod, thereafter cooling the fabric on the rods to solidify or the deformable composite material to set to shape and the tubes to become self supporting, feeding the fabric off the ends of the rods and cutting it to the required length.