#9.. John when you talk about sail , brings back memories of HMS Reclaim which although Think was built in the late 1950s also had a sail which was said gave her an extra knot weather permitting. Although well out of Service now , she was at one time the navies diving support vessel when I worked for the. MOD. From her in previous years certain records were made , and as I believe in a previous post about saturation diving rather think the record was barely over 600. Feet and may of been made from this vessel which all things considered was well done when comparing the equipment used then and now. Don’t think that record has been broken , as said today there is little point in endangering lives when not necessary. But that sail she had always stuck in my mind as being out of place, not so, in today’s thinking we may soon be going back to. Cheers JS.