Two of the Upholder class were built by Cammel Lairds in Birkenhead. They were the last boats to be built there.

Once water gets into a control room there are only small drains which lead down to the bilges to take the water away.

500 gallons/2000 liters does not sound much but is would come pouring down the hatches which are anly about a meter in diameter as a solid bore of water. It also equates to 2000 kgs of mass added to the boat, as the electrical power was knocked out they could not run the bilge and trim pumps to remove the water. Boats on the surface are in a fine state of trim.

The main battery on a boat does not have high voltages as was pointed out above, but it does have a high current.

All boats have a battery even nuclear powered ones. Should the reactor scram (shut down)the boat can then run on electric propulsion until the reactor is brought critical and self sustaining again. If the problem is going to be a long one and operational circumstances permit then the boat will come to periscope depth and snort deisal. If the boat is on a patrol in a sensative area then the captain will delay running deisals until the last possible moment. The snort induction mast poked above the surface would possibly give the boats position away even though they are covered with radar absorbany material. The exhaust mast is kept below the surface when dived at periscope depth.

Sometimes when in sensative areas a boat would reduce reactor power to a minimum, shut down nearly all of the air con' and domestic electrical services and proceed on battey power so that the boat was in an ultra quiet state. Use of the heads was also restricted and we used good old elsan chemical loos so that pumping of slop, drain and sewage tanks was reduce to a minimum

The batteries on a boat are huge. Over a meter tall and about half a meter wide and a third of a meter deep. The batteries on a boat like the Upholder class would be arranged in several groups that would allow them to be operated in series for short high speed operations or in parralell for more sustained but slower underwater speeds.

Snort deisaling would occur every few days to recharge the cells.

The Upholder class were designed in the 70's and built in the 80's. They were to replace the older (but excellent) Porpoise and Oberon class boats. I served on a coupl of P&O's as we called them as well as a marine engineer on nuclear powered boats. I never quite understood why we got rid of the conventional boats as they were much quieter than a nuclear boat at that time, plus they were of a shallower draft which permitted close in coastal operations.

The nuclear boats tended to be used for what were called 'sneakies', AKA intelligence gathering, particularly so during the Cold War through out the 70's and 80's.

Two good books on the cold war operations are;

'Blind Man's Buff' by Sherry Sontag and Christopher Drew. This covers US cold war work and while it is obvious it was not written by someone who served on boats it is still an excellent read and reveals some quite stunning operational patrols against the USSR.

'We Come Unseen' by Jim Ring. This covers the careers of 5 RN submarine captains from their time as Middy's to their Perishers course and command. One of my old skippers, Chris Wreford-Brown, features heavily. It is an excellent book and gives a good view of submarine operations and the personalities of the skippers but is a little more reserved in what it reveals.

'We Come Unseen' was the moto of the RN Submarine service. Those nasty buggers on surface ships changed it to 'We Come Unclean'.....can't think why ;-)