IT'S BEEN A WHILE since we last had a Wreck Tour of a submarine, and we have never had a tour of the classic submarine, a type VIIC German U-boat.
So this month we make up for it with the beautiful wreck of the U1021, a type VIIC/41 sunk by a mine off Trevose Head, on the north coast of Cornwall.
As is common with U-boats, the wreck of the U1021 rests canted over to port by about 45. For our tour, the shot has fallen just off the starboard side and forward of the conning tower (1). The seabed is at 51m on a high-water slack, or 45m on a low-water slack.
With the deck canted to port, it is straightforward to orientate yourself forward and aft. On reaching the conning tower, the first point of interest is the search or sky periscope (2), a small tube in front of the main body of the tower.
This is a deliberately small and therefore hard-to-spot periscope that would be raised first to make sure all was clear to raise the main attack periscope.
The outer cladding from the conning tower has all fallen away to leave just the central core, which is a part of the pressure hull. On top, the circular hatch (3) is closed. On the starboard side, a circular loop on a stalk is the antenna for a radio direction-finder (4). To port, a large U-shaped channel on the front of the tower is the bracket for holding the snorkel upright.
Behind the hatch, the larger attack periscope (5) rises through a conical support, the top adorned with a scrap of fishing net. Standing 6m above the seabed, this is the shallowest point on the wreck.
At the back of the conning tower, tubular air intake ducting leads down to the deck and is then routed aft between the pressure hull and the remains of the deck (6), to provide air for the diesel engines when the U-boat is surfaced.
Continuing aft, the aft torpedo-loading hatch (7) is closed, angled into the hull so that torpedoes could be slid down along and inside the hull for re-loading the single aft-facing torpedo tube. More ducting leading aft to either side of the hatch is the exhaust pipes from the two diesel engines.
To the starboard side, what looks like
a large air cylinder (8) is exactly that, and not an externally stored torpedo. Externally stored re-load torpedoes were of no use by 1945, when a submarine on patrol would rarely find conditions safe to surface at all, let alone for long enough to carry out the reload from external storage.
At the stern, the twin propellers are supported by A-frames in line with the aft hydroplanes (9), each followed by a rudder for manoeuvrability. The single aft torpedo tube (10) opens neatly between the two rudders.
Now heading forwards along the port side of the wreck, the seabed is littered with debris from the main deck. A lattice of ribs (11) that rests propped against the hull would once have supported the deck above the engine-intake ducting.
Below the conning tower, conical stumps are the mounts from 20mm and 37mm anti-aircraft guns. The larger aft-most mount (12) is upright, while the smaller mount (13) is on one side among debris from the conning-tower cladding and gun platform. The guns were only small, so could have decayed and become mixed up beneath the debris in this area.
Ascending a little to follow the port side of the deck, the snorkel tube is folded down and stowed in a recess in the deck (14). Of particular interest is the ball-valve assembly at the head of the snorkel, working on similar principles to the ping-pong ball valves that used to be found at the top of toy snorkels.
Next comes the forward torpedo-loading hatch (15). Like the aft hatch, this is firmly closed, though angled forward for loading torpedoes into the forward torpedo-room.
Continuing forward, the devastation where the U1021 struck the mine now becomes apparent. The bow has been broken off across the forward torpedo-room (16), coming to rest some 7m away.
In the gap rests another compressed air cylinder (17) that would once have been fixed between the pressure hull and the deck above. Just to port are two life-raft canisters (18). The U1021 was fitted with four such canisters, and these helped to identify the wreck.
Also broken from the bow is a pair of small bollards (19). The bow itself rests completely capsized past 90 on its port side. The outer doors for the four torpedo tubes are closed (20) and the starboard bow hydroplane stands intact (21).
For the bow to have been broken off and land this close to the main body of the wreck, the mine explosion must have been instantly catastrophic, the two parts of the wreck sinking instantly.
Which brings me to the last part of our tour, and in some ways the most significant. Approximately 10m off the starboard side is a rectangular box with small wheels in the corners (22), the anchor from the mine that sank the U1021.
With a full boatload of divers and lengthy decompression, skipper Chris
Lowe likes everyone to return to the shot for the first part of the ascent, and then decompress on a drifting lazy shot.

Thanks to Chris Lowe, Innes McCartney and members of the Go-Dive club.

GETTING THERE: Follow the M5 to Exeter, then the A30 past Bodmin to Indian Queens, then turn north on the A392 to Newquay.
HOW TO FIND IT: U1021 lies 6 miles west of Trevose Head at approximately 50 33.3 N, 005 11.6 W (degrees, minutes and decimals). Chris Lowe is keeping the precise GPS numbers quiet for while.
TIDES: In the big tides of North Cornwall, slack water is essential and occurs 1 hour after high and low water Newquay, with the low-water slack being considerably shallower.
DIVING & AIR: Atlantic Diver, skipper Chris Lowe, 01637 850 930, www.atlanticdiver.co.uk. Nitrox, oxygen and trimix are available, but check in advance to make sure that sufficient gas is in stock.
ACCOMMODATION: Chris Lowe can provide bunk-room accommodation. There are plenty of other options in Newquay, www.newquayguide.co.uk.
QUALIFICATIONS: The depth makes U1021 suitable for those with extended-range or normoxic trimix qualifications.
LAUNCHING: Slips at Newquay and Padstow.
FURTHER INFORMATION: Admiralty Chart 1149, Pendeen to Trevose Head. Ordnance Survey Map 200, Newquay, Bodmin and Surrounding Area. Deep Wreck Mysteries DVD, Mallinson Sadler Productions. The Loss Of U325, U400 and U1021 by Axel Niestle, www.uboat.net
PROS: A classic U-boat that is typically found in excellent visibility.
CONS: This wreck is towards the limits of air diving.

Life-raft canisters were among the features that helped to identify the wreck.

The core of the conning tower, the streamlining having broken away, showing the DF loop antenna and periscopes.

Small deck bollards broken from the bow.

The gun mounts have fallen to the seabed

rear torpedo-loading hatch

starboard propeller and aft diving plane

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U1021, U-boat. BUILT 1944, SUNK 1945
IF YOU STUDY U-BOAT HISTORIES, you will know that there is often more than one reason for one being sunk. Take the U1021, found by divers off the North Cornish coast very recently, writes Kendall McDonald.
Several highly respected books on German submarine losses in WW2 say that U1021 was sunk by depth-charge from the RN frigates HMS Conn and HMS Rupert on 30 March, 1945.
The date is nearly right, but this was not how this submarine met her end. In fact, she was the victim of a cunning Admiralty plot to put down a minefield especially to destroy U1021 and two other U-boats working the same inshore channel, much used by Allied merchantmen.
One of those three U-boats had incautiously sent a coded message to its base, basically saying: Come and join us, the Allied ships are using this channel to run along the North Cornish coast off Newquay and Padstow. Bring as many torpedoes as you can, you cant miss.
The British code-breakers cracked this almost instantly, and Navy minelayers worked at night to set up a deep minefield at 20m along the channel at the end of 1944.
The mines were deep enough to let the Allied ships go over them, but just at the sort of depth at which a following U-boat manoeuvring for a kill would hit them. We know that the minefield sank three U-boats, but are indebted to the leading British U-boat historian Innes McCartney for the identification of U1021. Innes was consulted soon after the wreck of the Padstow U-boat was found, and dived it shortly afterwards.
U1021 was a type VIIC/41 boat, which served with the 11th U-boat Flotilla based in Bergen and set out to patrol the approaches to the Bristol Channel on 20 February, 1945, commanded by Oberleutnant Willi Holpert with a crew of 42.
She was carrying a full load of 14 torpedoes when she picked up the steamer Rolsberg in the convoy lanes during the night of 14 March and stalked her submerged while waiting to get in a daylight shot.
Some time later, the Rolsberg heard a massive explosion somewhere near Trevose Head. U1021 had struck one of the string of mines in the Royal Navys trap. The mine had blown the bow of the
U-boat clean off, perhaps helped by the explosion of the torpedoes in her bow tubes. There were no survivors.
Innes quickly identified the wreckage as a VIIC/41, but the clinchers were life-raft canisters of a type carried only by U1021.