The Sinking
On the morning of the 26th January 1932 the M2 left the navel base at Portland for a routine exercise in West Bay . At 10:11 she radioed the depot ship HMS Titania stating she was about to dive at 10:30 . This was the last communication with the M2. At 16:16 she was officially designated as missing and a large-scale search was set in motion. Captain A.E. Howard of the Newcastle coaster Tynsider reported that at approximately 11:15 he saw a large submarine with the letter M painted on her side submerge stern first, he asked if this was normal. “No Submarine does that intentionally” was the reply. West Bay is locally known as the “Bay of a Thousand Wrecks” so there were many false alarms in locating the M2, it was only on the 3 rd of February that she was finally found, eight days after she had sunk.
She was lying on her side, with her bows floating clear of the seabed. By this time the operation had turned from a rescue mission into a salvage mission, as the crew were assumed dead. Ernest Cox, the salvage expert that had raised the German Battleships from Scapa Flow was hired to salvage the M2. In an operation lasting nearly a year, Cox managed to raise her to within six meters of the surface before a gale sprang up, sending her to her final resting place.
To this day it is not known exactly why or how the M2 sank. As the hanger door was open and the Parnell Peto plane was still inside the hanger, it is fair to assume that a launch was in progress. The M2 was a very large submarine and on surfacing would take a full 15 minutes to blow the ballast tanks completely. So the normal procedure when launching the plane was to surface and hold the boat on the surface with the hydroplanes while the ballast tanks were emptying. The best theory is that the rear hydroplanes failed, causing the rear of the submarine to settle in the water, eventually water would have gushed aboard via the open hanger door. Sending her to the bottom stern first, which fits with the observations of Captain Howard, and also explains why she was found on the bottom with her bows floating clear of the seabed.
Sixty men died when the M2 was lost. Most of the bodies still lie within her. She is a war grave and must be treated with respect.
The Dive
On my first dive on the M2 I had followed the shot line down to the seabed at 32 meters, there was no sign of the wreck anywhere. However turning around I saw a dark wall looming over us. The shot had landed just alongside the wreck. As with most submarines there is not a lot to see along the seabed so we rose to the deck level and started working our way along it. Its worth spends most of the dive time at the deck level, dropping down to the seabed at the bow and stern only. At the stern of the wreck are the rear hydroplanes and the rudders and prop shafts, the brass propellers were salvaged in 1932. All along the side of the hull are small regular holes, these are vents for the ballast tanks, almost every hole as a small creature living in it, sometimes crabs, sometimes Tompot Blennies. About half way along the stern section is a 12-pounder folding gun. The gun is folded up and lies flush with the deck plates.
Soon the bulk of the conning tower looms up, for some reason most of the divers never seem to get any further than the conning tower and it is always a bit like diver soup here. If you still have a good load of air left it is worth just swimming past the conning tower and head for the hanger in front of it. The hanger door opens downwards and can be seen forming part of the deck as you come to the hanger entrance. The hanger is about 10 feet wide and about 25 feet long. It is possible with care to enter the hanger. There is a large slope of silt half filling the hanger. Be very careful not to stir up this silt as it can totally destroy visibility. A diver has already died in the hanger unable to locate the exit. Just inside the hanger is the launch trolley. About six feet in front of the hanger are the launch rails, and in-between them the steam catapult used to launch the plane. Look hard in the holes around here, lobster and conger seem to live here. Continuing towards the bow you pass over some winches and pass the forward hydroplanes. The bow is surprisingly sharp and steep. Dropping down you can see the holes in the hull for the torpedo tubes. The actual tubes are within the hull, all you can see is the outer door. There are two tubes on each side of the bow, one on top of the other. Look in all the holes in at least one you will find a large conger eel. Returning back to the conning tower, look for the crane used in recovering the plane, which is on top of the hanger. Behind the hanger is the conning tower, complete with aerials and periscopes. The conning tower is surprisingly small, when the sub was operating on the surface there would be about six people crammed in this small space. After looking around here it is probably time to bag off and return to the surface. Watch out for boats when surfacing.
Dive site information
Today she lies in 32 meters of water west of Portland , about an hour and a half steam from Weymouth . She is laying on an even keel with the conning tower the highest point at a depth of around 20 meters. GPS position approx. 50 34.60N, 02 33.93W. The visibility can often be very good in West Bay . The M2 is always a busy dive site, with often as many as 6 boats diving her at slack water.
Other sources of information
Strike from beneath the Sea. Terry C. Treadwell. ISBN 0-7524-1704-5
Outlines the history of aircraft-carrying submarines.
http://www.divernet.com/wrecks/wtour5799.htm
http://www.liddiard.demon.co.uk/photoix/m2/