Divernet
UC-70 was a small U-boat, just 417 tons and 49m long. The armament included an 88mm gun, two forward-facing and one aft-facing torpedo tubes. These were outside the pressure hull and could not be reloaded underwater. But the main purpose of this submarine was mine-laying, with 18 mines loaded in six tubes in the forward part of the hull.
These small U-boats were designed to operate in shallow coastal waters, laying mine-fields across the entrances to ports and coastal shipping lanes, with the torpedo armament to take care of any other targets of opportunity.
On 28 August, 1918, UC-70s last victim was the 1100 ton steamship Giralda, torpedoed and sunk off Runswick. Later that day UC-70 was caught on the surface by a patrolling seaplane and bombed, the destroyer Ouse following up with a depth-charge attack.
The wreck today lies with its bows facing south-east in 27m of water, just three miles from Whitby harbour.
Diving UC-70 provided a couple of firsts for me: the first time I had dived off the Yorkshire coast and the first time I had dived a U-boat that was anything but a tangled mess of scrap metal. I had dived intact submarines from other nations - British, American and Japanese - but had never dived a U-boat, so I was looking forward to this one.
The buoy line was tied to an exposed rib at the forward end of the starboard ballast tank. The first thing I noticed was one of the mine-laying tubes (1). There are six of these in total, running vertically through the forward end of the hull. They look like a line of circular manholes with lips protruding about 20cm above the surface of the hull.
Originally this would have placed the ends of them flush with the outer hull, but this is now missing here.
In dock, mines would be loaded from above, three to a tube. Once in enemy waters they would be released from the corresponding openings in the bottom of the hull.
Turning forwards, a vertical shaft with a solid-looking cog on the end projects from the top of the hull (2). This might have been the drive for an anchor winch, or perhaps part of the mechanism for controlling the bow planes.
The robust inner hull is intact, but the outer hull is broken and absent in many places. The front of the inner hull is slightly domed. Forward of this would have been a streamlined bow section of the outer hull with two torpedo tubes. All that remains now is a shaft with the skeleton of a bow hydroplane on either end resting on the seabed and a few assorted steel plates (3).
There is no sign of the torpedo tubes. Perhaps they were salvaged for their high non-ferrous metal content.
Coming back along the port side of the hull, the remains of the ballast tanks start about level with the fourth mine-laying tube (4). The ribs of the ballast tank are mostly intact, but the plates have rotted through or even fallen clear in several places, making it easy to look inside.
Aft of the last mine-laying hatch is an open hatch (5). I didnt fancy doing any more than poking my head in, but nothing is visible below. It is hard to imagine a crew of 28 living inside a tube 3m wide and less than 50m long, most of which is filled with machinery.
Next comes the 88mm gun (6), still nicely aligned with the hull and presumably locked in travelling position.
Behind the gun is a section of mast that used to house the search periscope (7), then twisted plates where the conning tower has collapsed to port. At the top of the conning tower is a hollow mast, with the broken attack periscope retracted inside it (9).
Beneath the conning tower is a tough-looking metallic tube, unfortunately not a torpedo but a compressed air cylinder for blowing the ballast tanks (8). Further aft another similar cylinder protrudes from the remains of the ballast tank (10).

Immediately behind the conning tower, a pair of pipes and valves pro-trudes from the hull (11) I have no idea what their purpose was but, like many other fittings, they would have been flush with the long-gone deck.
Next is the aft hatch (12), also open and looking in slightly better condition than the forward hatch. At the stern the outer hull is more intact. Missing plates on the upper side reveal an arrangement of pipes and levers that would have controlled the rudder and rear hydro-planes (13), and launched the single rear-facing torpedo.
Almost at the stern a small rudder post is visible, then a cylindrical hole running back along the centre line of the hull is the stern torpedo tube (14).
The aft hydroplane assembly is on the seabed, a couple of metres off the stern. The construction is very similar to the bow planes, but a bit more broken up (15).
Looking back along the starboard side, one of the two propshafts is visible. The corresponding port shaft is buried beneath the seabed.
The outer hull on the starboard side is in a similar state to that of the port side, but raised a little above the seabed and without the remains of the conning tower. More compressed air cylinders can be seen protruding from broken ribs.
There is not a fantastic amount of marine life, but I found the UC-70 to be incredibly interesting from an engineering point of view. A submarine in a state of partial undress, with lots of interesting bits of mechanism sticking out.


Would your club or dive centre like to see its favourite wreck featured here If you would like to help John Liddiard put together the information for a particular wreck, why not invite him to come and dive it with you Write to John c/o Wreck Tour at Diver.

BETRAYED BY AN OIL SLICK  
Pilot Lieutenant Arthur Waring of 246 Squadron RAF hauled his new Blackburn Kangaroo bomber into the air at the end of the runway of Seaton Carew, near Hartlepool. His take-off was timed at 3pm on 28 August, 1918. The 920lb bomb load made him keep full boost on both engines as he climbed out to sea to start another anti-submarine patrol.

There were only eight Kangaroos in service in World War One, all at Seaton Carew. That month they had sighted 11 U-boats and attacked each one, but Lt Waring was about to give 246 Squadron its first U-boat kill.

At 3.30, Waring spotted a long track of oil on the glassy sea off Whitby. On the seabed at the head of that slick he saw a long, dark object, stationary. Waring dived straight along the oil line and dropped a 520lb bomb at its source. Huge air bubbles and more oil gushed to the surface.

The destroyer HMS Ouse saw the explosion and raced to the attack. Waring guided her in with flares, and Ouse released 10 depth charges into the centre of the black patch. More oil and air welled up, and it was clear from other debris that the submarine was finished.

A fortnight later RN divers led by Petty Officer Dusty Miller found the wreck. They entered and identified it as UC-70 of the Second Flanders Flotilla. She had left Zeebrugge for the Whitby area on 21 August, commanded by Oberleutnant Karl Dobberstein. She was believed to have been damaged in a new British minefield off the Yorkshire coast and to have been effecting repairs when spotted. There were no survivors from her crew of 31.



Divernet
Divernet
Divernet



TIDES: Slack water is 2 hours after high and low water at Whitby. Visibility is generally better on the high-water slack.

GETTING THERE: From the south, leave the A1 on the A64 past York and continue to Malton. Then follow the A169 through Pickering and past Fylingdales to meet the A171 just west of Whitby. From the north leave the A1 on any one of a number of roads to Middlesbrough and Teesside. Once south of the river take the A171 to Whitby. In Whitby, continue along the A171 until you are in the valley, then turn left towards the harbour. The marina area is on the right just after the railway station and the slip is at the far end.

DIVING AND AIR: Alan Holmes runs a RIB for up to six divers, 01947 600861. He has a small compressor and a number of cylinders for hire. The nearest commercial air station with nitrox is Dennys at Redcar, about 20 miles away, 01642 483507.

LAUNCHING: Marina slip in Whitby.

ACCOMMODATION: Local diver Tony Campbell runs the Lavina House guest house, 01947 602945. Whitby has a large seaside holiday industry with associated accommodation. There are some particularly picturesque campsites in the surrounding countryside which could provide an alternative to B&B or a hotel.

QUALIFICATIONS: This wreck is suitable for sports divers and equivalent.

FURTHER INFORMATION: Admiralty chart 134, River Tees to Scarborough. Admiralty chart 129, Whitby to Flamborough Head. Ordnance Survey map 94, Whitby & Esk Dale, Robin Hoods Bay. Dive Yorkshire by Arthur Godfrey and Peter Lassey. Whitby tourist information, 01947 602674.

PROS: Shallow and reasonably intact U-boat close to a convenient launch site.

CONS: Visibility can be poor, especially on the low-water slack.

Many thanks to Alan Holmes and Tony Campbell.

HOW TO FIND IT:

This is a small wreck and can be difficult to locate. It lies 3 miles north-west of the harbour entrance at Whitby and 0.6 miles off shore from Lythe church. Differential GPS co-ordinates are 54.31.597N 0.40.131W (degrees, minutes and decimals). Either use the GPS co-ordinates or from an approximate position follow the transit in until the sub shows on an echo-sounder. Alan Holmes usually leaves a buoy attached to the wreck.