Very good condition and popular with charter skippers. The M2 is is a great dive. Sadly the prop has gone, but virtually all the rest of the vessel is still there. The conning tower is home to a monster lobster, who dissapears back into safety at the first sign of an outstretched arm! There is all the usual life, sponges, pouting and pollack as well as the odd wrasse or two. Visibility is good and you can see a fair amount of the sub at once. A small scour runs at the base of the vessel, and anenomes stick to the hull in this dip. Mega. Well worth the effort and upright. Jib of recovery crane sticks out forward of conning tower. Hangar door open, aircraft removed during salvage. All hatches sealed with steel and concrete, except for conning-tower outer hatch which is open, but inner hatch is sealed like all others. This is a war grave, dive accordingly.

History:

[HSAC:]
Royal Navy Submarine. Left Portland for a routine exercise in West Bay west of Portland Bill. The last communication from M2 was at 10.30am. The most likely cause of loss was an accident or some failure while she was trying to fly off her seaplane, as on 18th March the body of Leading Seaman Albert Jacob was found in the hanger, followed by that of Leading Aircraftman Leslie Gregory on 1st July, wearing flying overalls.
There were no survivors from her crew of 60. The wreck has been found.
[HSAC:]
1600 ton Royal Navy submarine, built 1918 as K19. 296ftx24ft. Originally carried 12in gun (same as M1). In 1928 gun removed, replaced with hangar to carry folding-wing seaplane with catapult launch. Sunk: 26 January, 1932, while exercising off Portland, probably in attempt to surface and launch seaplane in record time. It’s believed hangar door was opened while still under water. All 60 of crew lost. Eleven-month salvage operation, headed by Ernest Cox of Scapa Flow fame, failed to raise her. Interesting link to M-2:

MANY DIVERS WILL HAVE HEARD OF, if not actually dived, the famous wreck of HMS M2. This British submarine sank off the south English Dorset coast and, since her rediscovery nearly 40 years later in 1970, has been a port of call for thousands of divers enjoying summer diving out of Weymouth.
At a friendly depth of 32m, M2 lies upright and intact, her bronze conning tower covered with jewel anemones and the crane that would once have lifted her seaplane back aboard still obvious on her foredeck.
M2 was the first submarine to carry such a seaplane. Her conversion to an aircraft-carrier was completed in 1927, before which time she carried a monster 12in battleship gun forward of her conning tower, in the same way as her sister-subs M1 and M3.

It was during peacetime, in 1932, that M2′s crew made a fatal error. Her hangar doors were opened too early, flooding her hydraulic systems and making her unstable. So she followed M1, which had sunk seven years earlier, to a watery grave at the bottom of the English Channel.
Within eight days the Royal Navy had used sonar to locate M2, though M1 remained undiscovered.
The M-class British submarines, developed towards the end of World War One, were unique. All three were fitted with 12in guns from a scrapped Majestic-class battleship and, using the “Dip Chick” method, would rise suddenly to the surface, fire a round and dive again – all in around 30 seconds!
Although top secret and experimental at the time, it was thought that no merchant vessel would survive a hit from these new weapons. The M-class submarines were completed before the war ended, but never used in combat, as the Navy feared that Germany, which dominated submarine warfare, might copy the design and wreak havoc.

On 12 November, 1925, M1 went missing while on exercise off the Devonshire coast. Her loss remained unexplained until the collier Vidar entered Vatara Harbour in Stockholm almost a week later.
Vidar’s crew had reported colliding with an unidentified submerged object off Start Point in the Channel, and her damaged bows revealed traces of a rare paint that had been used on M1.
Navy divers and survey vessels searched for the lost sub for a month before abandoning hope of locating her. Over the next 66 years, stories of M1′s location emerged occasionally, but no evidence was produced. It seemed certain that she was lost in deep water.

Then deep waters started to become more accessible, as mixed-gas diving gradually became mainstream.
The first claim to have discovered M1 was made by legendary salvage operator Silas Oates. I have often read about this character and his exploits, but his M1 tale was put to rest when the sub with the monster gun was found in water far deeper than he had claimed.
In 1991, Royal Navy survey vessel HMS Bulldog carried out a sonar survey of the area in which M1 had been lost, and discovered several submarine-type wrecks. Nelson McEachan, who today works for the UK Hydrographic Office, was on that survey team and told me its members were 99.9% sure that one of these vessels was the M1.

With no diving or ROV inspection, the report was inconclusive, but this was the most positive sounding so far.

Nelson’s position was finally verified on 18 June, 1999, when Weymouth skipper Graham Knott relocated the wreck along with submarine researcher Innes McCartney, his wife Patricia, Chris Hutchison and the late Keith Morris.

This small team became the first to dive to and see M1 in the 74 years it had been on the seabed. The wreck was McCartney’s Holy Grail, a giant sub in home waters, and the long hours of research he and Knott had undertaken had finally paid off. The team returned with video evidence that the legendary M1 had been seen again.

I will never forget hearing their triumphant news, as their cell-phone signals came back into range. I had not joined them at sea, as I was in hospital to witness the birth of my first daughter.
But on 2 August I joined Chris Hutchison for a further investigation. The M1 wreck sits on a silty seabed at 75m, with a least depth of 66m to the top of the conning tower. It is almost upright, 5m proud of the seabed with a slight list to port, and almost intact except for that huge 60 ton gun turret and operating mechanism. This has fallen on the port-side seabed only 2m from the main hull,
The gun barrel was obviously knocked off when Vidar collided with the sub, and has been picked up on sidescan sonar some distance from the wreck.

In front of the silhouetted conning tower is the area where the gun turret fell, leaving the circular mounting on which it sat. The mounting ring appears twisted a fraction to port, and closer study reveals how M1 met her fate.

Rather than sitting on the pressure hull, the mounting ring passes right through it, so as the Vidar knocked off the gun, water would have flooded the interior of the shell-room. With no air to blow the ballast tanks, it would have taken the vessel straight to the seabed.

So the gun was M1′s strong point and, it seems, at the same time its weakness.
Forward of the turntable, there is extensive damage to the top of the hull, and a V-shaped gash in the hull. Above, in the conning tower, an open hatch on the starboard side perhaps indicates an attempt made by the crew to escape. Behind the tower is another, much larger, hatch. Again, it is open.
Today, a large trawl-net drapes this relatively small conning tower, although you can still see the helm boss through the net, plus other interesting fixtures.

The conning tower would have accommodated only a handful of men, and the cut-out footholds they once used to climb from the decks below are evident among the white anemones that cover almost the entire wreck.

Further trawl-net hangs high between the conning tower and the stern. Chris Hutchison reported that a bronze hatch towards the bow is also open, enabling divers to view the crew’s chinaware, still stacked neatly on its shelves.

The props are intact, but once again draped in net, this time monofilament.
The outer hull casing shows signs of rotting, and in many areas has gone completely, leaving the underneath framework visible.

When good conditions prevail, the 300ft-long M1 provides a magnificent spectacle, but with these dives under my belt, I felt the urge to do a comparison dive, and joined one of the charter boats out of Weymouth.
M2 lies in Lyme Bay, a relatively short trip around Portland Bill. Its spectacular bow with knife-like razor edge, at the northern end of the site, provides the strongest comparison with the M1.

Visibility of 15m is not uncommon here in summer, and you can see the wreck disappearing into the distance.

M2 sits upright, and the tracks that once ran the seaplane off the deck can be followed easily from the bow to the hangar. The hangar door went during the salvage attempt and divers can see inside. Look hard enough and you can see the concrete once laid to seal up the hatchways leading below. One or two huge conger eels have made this home.

I was told by skipper Graham Knott that at one time the recovery jib used to recover the seaplane could be seen on the wreck and on the sonar from above, but it was lost six or seven years ago, probably trawled off.

The conning tower is intact, and as spectacular as you might expect. This is the best place to ask your skipper to shot.

The periscope tubes can still be seen and, moving aft, I saw a small gun in a recessed position inside the hull.

No diver can miss the hydroplanes both fore and aft and, approaching the stern, I saw the propshafts and their mounting brackets, though the props were nowhere to be seen.
It seems they were taken by a salvage team, long before the 1986 Military Remains Act came into being. The seabed is littered with brittlestars and wire hawser cable left from the salvage attempt.
Divers venturing off the wreck about 150m to the south-west will discover one of the huge flotation tanks that once lifted the wreck clear of the water before being lost again. In summer, as well as the usual light covering of dead men’s fingers, M2 hosts schools of pollack, wrasse and the odd lobster.
In poor visibility, the wreck can be quite moody, but if you want to dive a submarine that looks like a sub, this is it.

M1 and M2 are the only examples left of this type of submarine, as M3 was scrapped in the 1930s. If you haven’t dived either, try the approach Chris Hutchison and I took, which was to dive them in numerical order!

Both are protected by the Military Remains Act, which states that divers are not allowed to enter, tamper with or remove anything from the site. Visiting divers should be aware that many servicemen lost their lives in the sinking.

The Royal Navy’s Monitor class submarines were constructed as WW1 was drawing to a close. These submarines were designed to carry a 60 ton 12 in gun in front of the conning towers. Guns of this size were normally the main armament of battleships and could fire a 1 ton shell over 10 miles. The attack strategy was to search for an enemy ship at a periscope depth of 30 feet and with a suitable target in view, line up on the target with the gun trained at the appropriate angle. With only the last 6 feet of the barrel showing above the surface, the gun was fired and the submarine would dive to a ‘safe’ depth. These submarines can be seen as precursors to the missile launching trident/polaris submarines of todayThe M1 was sunk in an exercise after the war following a collision with a surface vessel which knocked the gun from its mount flooding it with water. This was the subject of an interesting “Journey’s to the bottom of the Sea” documentary screened on the BBC.

The M2, was converted to a submarine aircraft carrier following the removal of its gun with the construction of a watertight hanger which housed a two-seater biplane. The small, single prop Parnall Peto seaplane had specially designed folding wings in order to squeeze into the hanger, and was launched by a compressed air catapult along a short length of track. The theory was that the plane would fly around looking for enemy ships, note their position, and then land (on floats) as near to the submarine as possible. A winch attached to the top of the hanger would haul it back onto its rails where it was then slid back in and two sets of watertight doors closed behind it. The submarine would then dive on a course to meet said ships and finish the job with its torpedoes. It was during exercises in the English Channel on the morning of January 26th 1932 that she dived and never came up again. She was found 8 days later sitting upright and intact by Navy hardhat divers who reported that both hanger doors were open as well as the 21-inch hatch that connected the hanger to the submarine. Entangled in the wreckage of the plane which had crumpled and been pushed to the back of the hanger by tons of incoming water were the bodies of aircraft technician Leslie Gregory and Leading Seaman Albert Jacobs. The rest of the 58 crew had drowned inside where their remains rest to this day.

It is thought that in trying to improve their launch speed record, the hanger doors were opened a few seconds too early in anticipation of breaking the surface. If the access hatch had been closed after the two crewmen preparing the plane for launching had entered the hanger, the remaining crew would have survived. A salvage operation immediately commenced but was called off just before Christmas after 11 months of intense effort by 26 divers logging 1500 dives.

The first thing you notice diving the sub is its size – I have dived a number of submarines/Uboats of this era which were generally much smaller. To accommodate the gun these submarines had to be big and their size is comparable to submarines in use today. At 100m long it is longer than the Hispania and it sits upright on the bottom with a max depth of 35m. Our skipper had shotted the conning tower and we still had a bit of a current on the wreck when we descended, making it quite hard work to reach the wreck. On hitting the conning tower, I let my breathing rate calm down then we followed the submarine towards the stern. It was quite easy to tell we were heading in that direction even in poor vis (we had probably 5m) as the conning tower is shaped aerodynamically with a kind of aerofoil point towards the stern. At the stern it was possible to the prop shafts sticking out of the back of the boat, along with the rudders and steering gear.

After this we swam back to the conning tower and past this to the aircraft hanger noting the winch above the entrance which was used to bring the boat on board. The only part of the submarine’s interior that is accessible is the hangar, there is quite a lot of silt in here which can be stirred up easily making the poor vis even worse. The poor vis combined with the knowledge that the hangar was the cause of the sinking makes it quite a spooky experience exploring this area. Not long after we entered, the hangar started to get crowded, and a silty, as another boat load of divers joined us on the wreck – time for a sharp exit. Following this we just then had time for a quick look at the launch rail in front of the hangar before making our ascent. Another indication of the submarines size as we were only able to view half of it, leaving more to view on a return visit.

Acknowledgements
The M2 – The only submersible aircraft carrier

History

The Royal Navy’s Monitor class submarines were constructed as WW1 was drawing to a close. With the exception of the M1 class completed in April 1918, they never engaged in military action. The Monitor class was unusual in that in addition to torpedoes, their main armament was a monster gun weighing 60 tons with a 12-inch bore positioned in front of the conning tower. This gun could elevate to 20 degrees, depress to -5 degrees and train left or right by 15 degrees. Their modus operandi was to search for an enemy vessel at a periscope depth of 30 feet and with a suitable target in view, line up on the target with the gun trained at the appropriate angle. With only the last 6 feet of the barrel showing above the surface, the gun was fired and the submarine would dive to a ‘safe’ depth.

The M2, M3 and M4 were completed during 1919 – 1920 and with the Washington Disarmament Treaty of 1920 stating that no submarine could have a gun larger than an 8 inch; the M2 and M3 had their guns removed. The M3 was converted to a very successful experimental mine layer carrying 100 mines in a free flooding casing bolted to the deck that laid them over the stern by means of a conveyer belt. The M4 had the least illustrious career of the class in that with construction on her cancelled during the Armistice, she found herself surplus to requirements. For some reason she was completed anyway and launched successfully down the slipway; whereupon she immediately did an about turn back to the builders yard to be hoisted out and cut up for scrap.

The M2 was also converted to something experimental as her sister the M3 – the construction of a watertight hanger housing a two-seater biplane made it the worlds first and still the only submersible aircraft carrier. The spotter plane was the brainchild of submarine commander Sir Max Horton who was convinced that future power in offensive maritime strategy would lie in submarines and planes, not ships. He petitioned the top brass to combine the two, which they agreed to by building the hanger on the portion of deck that the gun once lay. The small, single prop Parnall Peto seaplane had specially designed folding wings in order to squeeze into the hanger, and was launched by a compressed air catapult along a short length of track. The theory was that the plane would fly around looking for enemy ships, note their position, and then land (on floats) as near to the submarine as possible. A winch attached to the top of the hanger would haul it back onto its rails where it was then slid back in and two sets of watertight doors closed behind it. The submarine would then dive on a course to meet said ships and finish the job with its 8 torpedoes.

The crew was proud of the speed in which they could surface and launch the plane and were constantly trying to break their 12 minute record. It was during exercises in the English Channel on the morning of January 26th 1932 that she dived and never came up again.

She was found 8 days later sitting upright and intact by Navy hardhat divers who reported that both hanger doors were open as well as the 21-inch hatch that connected the hanger to the submarine. Entangled in the wreckage of the plane which had crumpled and been pushed to the back of the hanger by tons of incoming water were the bodies of aircraft technician Leslie Gregory and Leading Seaman Albert Jacobs. The rest of the 58 crew had drowned inside where their remains rest to this day.

It is thought that in trying to improve their record, the hanger doors were opened a few seconds too early in anticipation of breaking the surface. If the access hatch had been closed after the two crewmen preparing the plane for launching had entered the hanger, the remaining crew would have survived. A salvage operation immediately commenced but was called off just before Christmas after 11 months of intense effort by 26 divers logging 1500 dives.

The Wreck today

70 years later the M2 is still sitting perfectly intact and upright on a sand/crushed shell substrate at 110 feet. All access hatches were sealed shut before commencing the salvage attempt so there is no access within. The exception is the hanger itself, which is still open and to most divers is the highlight of the dive. Being current free a considerable amount of silt has settled in there, covering the infamous 21-inch hatch, so it is important to be the first dive group on site before other divers stir it all up to the extent that even the most powerful torch won’t illuminate more than a few inches. Outside the hanger in a recess lying parallel to the rails is a compressed air cylinder not much bigger that the one on your back that provided the initial propulsion to the plane. When the track ends you continue down to the bow until you bump into the hydroplanes and then the 4 outer openings for the 18-inch torpedo tubes, two on each side. Swimming back along the hull you may notice bits of cable and odd shaped bits of metal nestling in the sand, these are not parts of the submarine but discarded/broken bits from the salvage attempts. Continuing past the conning tower, the shallowest part of the dive, you come across the 3-inch aft gun. This is not standing proud to the deck but lying flush with it. When the submarine surfaced it was mounted on a hydraulic platform that ‘popped up’. The stern has another set of matching hydroplanes, two prop shafts and the rudder. The conning tower offers the usual assortment of periscopes by which time you are definitely well into deco and its time to start heading up.

Without stating the obvious there is a big difference doing this site when the visibility is good as opposed to when it is poor – which is most of the time. In poor visibility it can be a little dull as the hull is not dissimilar to a long, smooth, cigar shaped boulder and because the boat is intact there are few nooks and crannies for critters to hide in. With good visibility this is a very, very special dive.

Technical Specifications

Displacement: 1610 tons at surface, 1950 tons submerged
Speed: 15 knots at surface, 9 knots submerged
Length: 296 feet
Beam: 25 feet
Propulsion: Two Vickers 12 cylinder 2400 hp diesels,
Two electric double armature motors – 400 hp each

The M 2 however is in within the range of most sports divers and is a very popular dive. She was completely different from the M 1 in the fact that she had no gun but carried a seaplane in a deck hanger. (Honestly, you could not make this stuff up.) The seaplane called the ‘Parnall Peto’ had folding wings so that it could fit inside and was launched by means of a catapult.

The aircraft was supposed to be used for reconnaissance purposes but the tactical disadvantages are obvious. The submarine had to remain on the surface for extended periods during the launch and recovery of the seaplane and this made her extremely vulnerable to enemy attack. In the end the experiment was a disastrous mistake. On the 26 January 1932 the M 2 was exercising in West Bay just off the Dorset coast, when she was seen to dive stern first by the captain of a freighter, which was passing by. She never resurfaced and it took the Navy nearly 8 days to find her lying on the bottom in 106 feet of water.

An inspection of the wreck revealed that her hanger door was wide open and so was the hatch leading to the control room. It would seem that the hanger door was open before she had properly surfaced and attained full buoyancy. Whatever the reason her 60 officers and men all perished.

This is another wreck that I have yet to dive as it’s a bit out of my area. Still some of my friends have dived it and one shot some video footage in August 1998, and it’s from this that I make the following brief observations. By the way this wreck has not been put on the restricted list yet and all the charter skippers still dive her.

The M2 is lying upright on a rock and silt bottom in about 106 feet of water. Since the submarine is 296 feet long with a beam of nearly 25 feet there is a lot to see. The hull is in quite good condition and has appeared to withstand the ravages of time pretty well except for the deck plates, which has great holes in it. Towards the bows you can see the remains of either the catapult or the anchor winches, and the bow anchors are nice and secure in their hawseholes, with the forward hydroplanes still intact.

On her sides, the hull is covered with a thin weed, deadmens fingers and plumose anemones. As you work your way towards the conning tower you soon see the gaping hole of the aircraft hanger. You can still go inside but it is quite silted up with quite a lot of steel plate scattered all around. The conning tower rears up very impressively with the remains of the periscope still pointing in vain towards the surface. Swimming down towards the stern the deck plates still look in poor condition, and since there was some salvage done on the wreck in 1932-33 it comes as no surprise to see that the twin propellers are missing, but the rudder is still intact and you can swim right underneath the propeller shafts and it makes you realise that the M 2 was a big boat, roughly the size of a frigate. Back up to the conning tower to play Captain, and a final look into the hangar and that’s the end of the dive. The M 2 looks well worth a visit to me.

Having defied an 11-month salvage attempt after its sinking, this undamaged and unique wreck has become a popular dive site in the waters of Lyme Bay. Frequent visitor John Liddiard reveals his route.

The M2 is a one-of-a-kind submarine aircraft carrier which sank off Portland in 1932 during routine exercises (see panel). It is 90m long, still in one piece, and sits upright on the seabed at a depth of about 35m, with the bows pointing north-north-east.
As a wreck tour it gave me a bit of a problem – what can you say about diving an intact submarine with no holes to explore? Except, perhaps, that it is a unique vessel and can be covered in one dive with minimal decompression, which is probably why it is one of the most popular wrecks in Lyme Bay.
A good charter-boat skipper will drop a shotline right across the conning tower of the M2, an ideal place to start and finish a dive (1). As you descend, your first sight of the submarine will be a selection of masts and periscopes rising from the conning tower.
The tower’s deck, which will be your point of arrival on the sub, hosts some large and colourful anemones and is often surrounded by large shoals of fish. But as it is shallower here than elsewhere on the wreck, save having a good look around until the end of your dive.
First, swim along the top of the seaplane hangar and recovery winch (2), to have a look inside the hangar (3). At the back is a bank of fine silt that is invariably stirred up by the first few divers who venture inside, so try to be first there if you can!
All other openings in the submarine’s pressure hull have been sealed, presumably during the salvage attempts, so this is the only opportunity to go inside the wreck.
From the hangar I like to follow the launch rails (4) towards the bows. Beside the rails, at a depth of 30m, is a grated decking the crew would have used when recovering the seaplane. Gaps in the rails are often home to crabs and conger eels. I have even seen the occasional lobster hiding here. Forward of the rails is a large single bollard, or capstan (5), and various small deck fittings and valve openings that are home to tompot blennies.
The bows (6) are a straight vertical edge with a full covering of anemones. There is a small anchor winched in tight against the starboard bow.
The main points of interest here are the outer openings for the four 18in torpedo tubes (7). These are slots with square backs that go right through the bows. The actual tubes are inside the bows of the submarine. These holes seem to serve as a designer condominium for conger eels.
Below the bows, the sandy seabed has been scoured by the tide to give the deepest point of the dive at 35-36m – a good hiding place for crabs and lobsters.
From the bows, follow either side of the submarine to the stern. It is worth rising slightly to inspect the bow hydroplanes (8) before moving quickly towards the stern following the sides of the submarine, which are almost featureless except for a dense carpet of hydroids and the occasional clump of dead men’s fingers. Nevertheless, keep an eye out for discarded bits of salvage equipment, particularly amidships (9). The occasional small opening could be home to some interesting marine life.
At the stern the two propshafts, keel and rudder (10) are covered in anemones, fed by the strong current that whips around the end of the wreck when the tide is running. This can also be a good location for large shoals of bib and poor cod.
Having seen the stern, ascend to deck level past the rear hydroplanes (11) and make a quick swim back to the conning tower. On the way you will pass the “disappearing” 3in gun platform (12). The gun itself is not visible, being in its lowered position flush with the surface of the platform.
Back at the conning tower you can use any remaining time and air to explore more thoroughly among the anemones and marine life of the periscopes and other fittings.

In 1927 HMS M2 became the world’s first undersea aircraft carrier – a submarine carrying a small two-seater seaplane in a watertight hangar, writes Kendall McDonald. 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 was proud of the speed with which it 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 the crew. 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.