Method of manufacturing a pressure vessel

A method of manufacturing a pressure vessel, the pressure vessel including a section having a longitudinal axis, the section comprising a wall which extends around the longitudinal axis to define a boundary of a sub-chamber, the section having a first end spaced apart from a second end along the longitudinal axis, the section being open at the first end to define a first opening to the sub-chamber, the section being open at the second end to define a second opening to the sub-chamber, the method comprising:

• dividing the wall into a first segment and a second segment, the first segment of the wall extending from the first end to the second end, and having edges extending from the first end to the second end;
• separating the first segment from the second segment such that the second segment of the wall is provided with longitudinally extending edges extending from the first end to the second end, spaced apart by a gap;
• fitting apparatus onto the first segment;
• and
• re-attaching the first segment and the second segment by relocating the first segment in the gap defined by the edges of the second segment and joining the first segment and second segment along their edges so the apparatus is housed within the sub-chamber,
• wherein the pressure vessel is a submarine.