Dodgy moments in submarines ... and the changing density of sea water
During my days in submarines, I and several others spent far too much time down near the Falkland Islands for our liking. This was in the early 1980s, when we were conducting ‘back to back’ patrols of thirteen weeks or more down there. The tedium was broken up by many moments of excitement, most of which are too highly classified to be shared in an open forum. However, one moment of excitement I can share, and which is described in my novel, The Custom of the Trade, was the fun and games in trying to return to periscope depth (PD) when in the equatorial region.
The sea at the Equator is constantly heated by the sun. As a result, the top 120 feet or so of water is at a much higher temperature than that at lower depths. This makes the water less dense and a noticeable barrier forms between this warm water and the denser water below. Something similar occurs in both the Dardanelles and the Baltic due to the amount of fresh water pouring into the denser saline sea.
On my first patrol ‘down south’, I was responsible for manoeuvring the submarine to PD. I went through the usual routine of giving the submarine ten degrees of bow up angle, increasing speed and pumping out 400 gallons of water. However, we were heavily laden with a full war complement of torpedoes and missiles, and all the food necessary to feed us for three months. To everyone’s surprise, the submarine became stuck at about 120 feet. Like Richard Miller in my novels, our CO worked out the reason and ordered us deep again to prepare for a second attempt. I prepared for it by pumping out a total of 2,000 gallons of water. The CO then ordered twenty degrees of bow up angle and 50% more revolutions for the next attempt. As soon as we reached 150 feet, I then had to start flooding 2,000 gallons of water quickly back into the submarine, take off the bow up angle and reduce the speed for fear that we might accidentally surface. It all went to make a normally routine evolution into something exciting. We soon adapted to and mastered the new routine, but on the return from my last South Atlantic patrol, something more life-threatening was to occur.
As so often happened in our elderly submarine, we had an engineering defect. The senior engineering officer advised the captain that we would need to shut down the reactor to repair the defect. This would mean that we would be reliant on the battery for all power and, thus, the power-hungry air conditioning would not be available. Accordingly, the engineer persuaded the captain that we should conduct the repair dived, in the cooler water of the deep instead of on the surface. Even so, the temperature rose steadily to unbearable levels in the engineering compartments, in the after section of the submarine. Some of the engineers fainted and had to be dragged forward, to the cooler part of the submarine, to revive. The repair went on for longer than expected and the battery power was draining fast, to the extent that unless the defect was fixed quickly, we would not have enough power to restart the reactor. With no power from the reactor to purify the air, like the submariners in my books, we all began to suffer headaches from carbon dioxide levels 100 times those normal. The captain ordered all non-essential personnel to retire to our bunks to conserve oxygen.
Clearly, I was destined to become a writer even then. A young officer, I had too much imagination for my own good. I realised that the situation was becoming desperate. Without the precious reactor, we had insufficient power to reach the surface and the air was deteriorating. I imagined the submarine as a floating tomb several hundred feet beneath the surface like some form of underwater Flying Dutchman. I remember that I was not afraid to die, but I just accepted it as my lot. As submariners, we knew the risks and dealt with them. However, I regretted nobody would ever know what had happened. It wasn’t something one discussed with one’s fellow officers. That would have been un-British and ‘un-officer like’. Like them, I turned into my bunk and went to sleep, never expecting to wake up!
A few hours later, I suddenly awoke on account of a strange noise. It slowly dawned on me that it was the noise of the diesel engines starting. That meant we had to be at PD or on the surface. I felt the draught of fresh air and smelt the stench of sea water, and worked out that I was not just alive, but we were on the surface. It transpired that our gallant engineers had finally fixed the defect and managed to restart the reactor. The captain had then taken us back to the surface to re-charge the batteries. Like cats, submariners have nine lives and we had just used another.