We boarded our boat and headed off into the choppy waves around Portland Harbour, our course set for the M2, the world's first undersea aircraft carrier.
In 1927 a submarine called the M2 carrying a small two-seater seaplane in a watertight hangar left the English coast. The seaplane, which had folding wings, was launched by catapult off a runway on the deck. When it landed near the sub, it was hoisted on board and into the hangar by a specially designed small crane.
The M2's crew were proud of the speed with which they could launch the little floating plane. Rising to periscope depth, the submariners would check around for enemy ships, surface, open the hangar door and catapult the plane off on its flight. They were constantly trying to beat their own speed record. It was this speed which was to kill all of them.
The M2 dived at 10.11am during exercises off Portland on 26 January, 1932, and disappeared. On 29 January all hope was officially abandoned for the 60 crew aboard. It took eight days to find her. The first divers discovered that the hangar door was open with the plane still inside. The hangar had apparently been opened while she was still underwater.
A salvage operation retrieved the plane, but after 11 months and a total of 1500 dives involving 26 Royal Navy divers, the Admiralty had to admit defeat over the submarine. On 8 December, 1932, the M2 was left to rest forever on the seabed off Portland.
Sitting at just a hair shy of thirty metres we would drop down to the M2 and visit the vessel for twenty minutes and then spend about fifteen minutes slowly ascending to the surface. Now, before we went in I knew the visibility would be poor but hadn't quite expected things to be as dark and dismal as they actually were
I went down with Tim, one of the finest divers in our club, and as we dropped below twenty meters is got really dark. It wasn't quite a night dive, but it was close. All I could see without my light was a dark dim hue of green filtering down on me from far above. We moved quickly visiting the hanger, radar, firmpoint for a mounted gun, and a number of other spots of interest before we had to consider ascending. We slowly made our way up surfacing ten bar above our reserve of fifty. So while dark and dreary all did go rather well.
In the afternoon we ran a much more relaxed dive on the countess, an iron paddle steamer that sank inside the harbor. Again, visibility was awful, but now at least I expected it. On the whole the dive was uneventful.
On the following day we again boarded our boat and headed off into the ocean. However, this time the waters were far more fierce. The waves were huge and breaking over the front of the boat splashing water over all of us on deck. We were making our way out to a bit of wreckage that was thought to be the St. Dunstan, a mine sweeper that wasn't very good at mine sweeping...
On September 23rd 1917 she was on route from Portsmouth to Pembroke when there was a large explosion on her port side. She quickly started sinking and unable to launch the one lifeboat that had not been blown up the crew abandoned ship by jumping over the side. They were quickly picked up by the escorting trawlers. It was soon discovered that two men were missing, but before they could be found the St Dunstan capsized and her boilers exploded.
Theresa and I kitted up ready for a dive that we expected to be challenging. We knew the visibility was going to be awful and expected a current to make things particularly challenging. As we descended we learned two things: we were right about the visibility and wrong about the current. So rather than getting flung around by a current on a pulverised wreck we were simply wandering in the dark... so better than we had anticipated.
Considering the conditions we decided to set some very conservative turn around points so that we would be certain to have enough air to make it back and have a safety reserve. We decided that if we reached ten minutes of bottom time, reached the the 110 bar mark on our tanks, or were within one minute of hitting madatory decompression time on our computers we would being an ascent.
As we slowly finned along the bottom looking at bits of wreckage in the tiny pools of visibility that our torches afforded us we noticed that our tanks were both getting close to the point of 110 bar. I motioned that it was time to send up a marker buoy and Theresa started sorting it out. While she did this I move up just a bit and hit my head on something. As I looked up I noticed that the dim green hue that had normally represented the distant surface was gone. All was black. I shined my light and realised that there was a metal cieling above me! How on Earth had we managed to swim inside something so large? I guess it was just the terrible visibility. Anyway, I motioned to Theresa to not send up the buoy since we were underneath something and she stopped with a look of confusion on her face. I shined my light up and she immediately understood.
We searched around together for a way out and found one after a minute or so. Again Theresa started setting up the bouy, but this time as she did it she sank down to thirty metres! I came over to help her and she handed me her completed buoy to fill. I went to fill it and missed, the bubbles shot out all over not going inside the bag at all. We tried once more, well aware of the fact that time and air were short. The air went in and shot the buoy to the surface. I made my way to twenty metres faster than my computer was happy with but I was getting close to having to invade my emergency reserve of air and I didn't want to do any more of that than was strictly necessary. Theresa, having not shot off a lot of air for the buoy at 30 meters came up more slowly below me. We didn't completely lose site of eachother and we were both hanging on to the same buoy reel, but we really should have stayed together.
From twenty metres we ascended very slowly, covering about three meters every minute. By the time we made it to the top my air was down to twenty bar, well into my emergency reserve. I can only imagine how badly things would have gone if we hadn't set such a conservative turn around point in the first place. Overall, I learned a valuable lesson: don't dive in unknown places in horrendous visibility, you can enter overhead environments without even noticing it. Anyway, I've chalked that one up to experience. Live and learn.