On the night of 22/23 November 1914, U-18 under the command of Kapitanleutnant Heinrich von Henning was on station east of Kirkwall trying to find a way into Scapa Flow where the Grand Fleet was, with a view to sinking as many ships as possible. As he proceeded south on the flood tide towards the mouth of the Pentland Firth, he decided to attempt an attack through the southern entrance to the Flow through Hoxa Sound and he calculated that he would arrive at the Pentland Skerries just as the tide turned to ebb west through the Firth. He was on the surface, replenishing his air and charging his batteries when the lighthouse came on, indicating that the Fleet was sailing. In wartime, lighthouses were extinguished unless friendly shipping was passing, which knowledge U-Boats put to deadly use in both wars. He navigated to the Skerries Light, submerged at slack water and turned into the Firth.
The Pentland Firth is one of the most hazardous seas in the world for surface ships, in daylight, even when they can see clearly as they navigate among the islands, so the dangers to a primitive submerged submarine trying to go round the islands are hair curling with all the eddies, cross tides, swirls and currents. These were increased by the fact that the waters were patrolled and kept under observation from shore stations.
U-18 reached Swona, which was inhabited by the Rosie family at the time, at dawn and entered Hoxa Sound at 11am to see only a few destroyers and trawlers through her periscope. None of these offered a target worth to von Henning risking his boat and crew for, so he turned at 11.20am to position himself to attack two destroyers which were coming out and would be in his line of fire shortly, further south in the relatively open waters of the Pentland Firth.
However, his periscope was seen by the steamer Tokio and she had given the alarm. The destroyers that von Henning had seen moving were actually the first of the flotilla coming to attack him. They were followed by other destroyers and several trawlers, among which was the Peterhead trawler Dorothy Gray, PD 533, under the command of Skipper Alexander Youngson. There are two versions of what happened next. The official one is that the Dorothy Gray proceeded with the flotilla and pursued U-18 at eight knots. The unofficial version, given by an eyewitness, was that the trawler had been in Longhope having her engine repaired and most of her crew were ashore, when Action Stations were given. She sailed with only five men aboard, limping along at about three to four knots, rapidly falling behind the rest of the flotilla, which were doing seven or eight knots.
The U-18 lay deep as the anti-submarine patrol rounded Switha and fanned out across the open water in a general south-westerly sweep, passing over her. Von Henning waited patiently until the noise of their propellors faded into the distance, coming to periscope depth now and again to check both where the flotilla was and where the tides were putting him. He was about 1.25 miles south-west of Hoxa Head, came up yet again to periscope depth, when the U-Boat was struck a tremendous blow which knocked her on her beam ends and bent her telescope at right angles. She had come to the surface under the stem head of the Dorothy Gray, whose slow turning propellor no-one had detected. The Dorothy Gray ran into U-18 rather than rammed it deliberately and the shock dislocated the hydrophone motor and the reserve steering gear. According to Youngson's report he chased the U-18 for 12 minutes before ramming it, but there is no explanation officially why the other vessels did not join in the hunt, as Youngson was duty bound to report that he had detected one. Nor is there any explanation why the flotilla was so far away from him. Whatever happened, von Henning was now submerged in a blind, disabled U-Boat in the Pentland Firth, while on the surface the Dorothy Gray was blowing her siren to attract the attention of the others who were mostly at Dunnet Head. She succeeded and as the leading destroyers raced back von Henning tried dead reckoning navigation to get him to the east and the relative safety of the Moray Firth. He hit a rock at a depth of 160 feet, shot to the surface, was rammed by the trawler Kaphreda, which damaged the deck slightly and he dived again with the whole flotilla gathered round him. Somehow he shook them off and must have thought he was clear when he ran into the Pentland Skerries. This time her hull was breached and von Henning had to surface, flying a white flag to prevent attack. The flotilla was three miles away and took some time to notice him. Two destroyers rushed over and von Henning and his crew surrendered. Of the twenty-seven crewmen on board, one man drowned and twenty-six were picked up by HMS Garry.
The Admiralty Prize Court awarded the skipper and crew of the Dorothy Gray £500 as opposed to the £200 normally paid for sinking or capturing a submarine. The money was divided as follows; Master £70, Mate £20, Chief Petty Officer £20, £16 to each of the four Petty Officers, £8 to each of the four Able Bodied Seamen, £6 each to the two Deckhands, two Engine Hands and the Coal Trimmer.
The U-18 was ordered on 6 May 1910. She was built at Kaiserliche Werft Danzig and cost 2,333,000 Goldmark. She was laid down on 27 October 1910, launched on 25 April 1912 and commissioned on 17 November 1912. She was a German Type U-17 submarine with displacement 564 tons (622 short tons) surfaced and 691 tons (762 short tons) submerged. Her length was 62.35 m (204 ft 7 in), beam 6 m (19 ft 8 in), height 7.30 m (23 ft 11 in) and draught 3.40 m (11 ft 2 in). Her propulsion was through 2 shafts, driven by 2 × 2 Körting 8-cylinder two stroke paraffin motors with 1,400 PS (1,400 hp), 2 × AEG electric motors with 1,120 PS (1,100 hp), delivering 550 rpm surfaced, 425 rpm submerged. Her speed was 14.9 knots (27.6 km/h; 17.1 mph) surfaced, 9.5 knots (17.6 km/h; 10.9 mph) submerged. Her range was 6,700 nautical miles (7,700 mi; 12,400 km) at 8 kn surfaced, 75 nautical miles (86 mi; 139 km) at 5 kn submerged. Her test depth was 50 m (164 ft 1 in). She had a complement of four officers and twenty-five men. Her armament was 4 x 45 cm (17.7 in) torpedo tubes, (2 each bow and stern), with 6 torpedoes.
U-18 served as part of the German Imperial Navy II Flotilla. From 1 Aug 1914 – 23 Nov 1914 she was commanded by Kptlt Heinrich von Henning and from 1 Aug 1914 – 23 Nov 1914 she undertook three patrols, but had no victories.
The wreck of the U-18 now lies in a depth of around 70m at possible position 58.42.128N, 02.48.08W. She lies in a trough between sand waves and is a difficult dive due to the strong tides of the Pentland Firth The wreck is remarkably intact, standing upright with the deck plating rotted through and a large gouge at the stern where the ramming took place.
The Pentland Firth is one of the most hazardous seas in the world for surface ships, in daylight, even when they can see clearly as they navigate among the islands, so the dangers to a primitive submerged submarine trying to go round the islands are hair curling with all the eddies, cross tides, swirls and currents. These were increased by the fact that the waters were patrolled and kept under observation from shore stations.
U-18 reached Swona, which was inhabited by the Rosie family at the time, at dawn and entered Hoxa Sound at 11am to see only a few destroyers and trawlers through her periscope. None of these offered a target worth to von Henning risking his boat and crew for, so he turned at 11.20am to position himself to attack two destroyers which were coming out and would be in his line of fire shortly, further south in the relatively open waters of the Pentland Firth.
However, his periscope was seen by the steamer Tokio and she had given the alarm. The destroyers that von Henning had seen moving were actually the first of the flotilla coming to attack him. They were followed by other destroyers and several trawlers, among which was the Peterhead trawler Dorothy Gray, PD 533, under the command of Skipper Alexander Youngson. There are two versions of what happened next. The official one is that the Dorothy Gray proceeded with the flotilla and pursued U-18 at eight knots. The unofficial version, given by an eyewitness, was that the trawler had been in Longhope having her engine repaired and most of her crew were ashore, when Action Stations were given. She sailed with only five men aboard, limping along at about three to four knots, rapidly falling behind the rest of the flotilla, which were doing seven or eight knots.
The U-18 lay deep as the anti-submarine patrol rounded Switha and fanned out across the open water in a general south-westerly sweep, passing over her. Von Henning waited patiently until the noise of their propellors faded into the distance, coming to periscope depth now and again to check both where the flotilla was and where the tides were putting him. He was about 1.25 miles south-west of Hoxa Head, came up yet again to periscope depth, when the U-Boat was struck a tremendous blow which knocked her on her beam ends and bent her telescope at right angles. She had come to the surface under the stem head of the Dorothy Gray, whose slow turning propellor no-one had detected. The Dorothy Gray ran into U-18 rather than rammed it deliberately and the shock dislocated the hydrophone motor and the reserve steering gear. According to Youngson's report he chased the U-18 for 12 minutes before ramming it, but there is no explanation officially why the other vessels did not join in the hunt, as Youngson was duty bound to report that he had detected one. Nor is there any explanation why the flotilla was so far away from him. Whatever happened, von Henning was now submerged in a blind, disabled U-Boat in the Pentland Firth, while on the surface the Dorothy Gray was blowing her siren to attract the attention of the others who were mostly at Dunnet Head. She succeeded and as the leading destroyers raced back von Henning tried dead reckoning navigation to get him to the east and the relative safety of the Moray Firth. He hit a rock at a depth of 160 feet, shot to the surface, was rammed by the trawler Kaphreda, which damaged the deck slightly and he dived again with the whole flotilla gathered round him. Somehow he shook them off and must have thought he was clear when he ran into the Pentland Skerries. This time her hull was breached and von Henning had to surface, flying a white flag to prevent attack. The flotilla was three miles away and took some time to notice him. Two destroyers rushed over and von Henning and his crew surrendered. Of the twenty-seven crewmen on board, one man drowned and twenty-six were picked up by HMS Garry.
The Admiralty Prize Court awarded the skipper and crew of the Dorothy Gray £500 as opposed to the £200 normally paid for sinking or capturing a submarine. The money was divided as follows; Master £70, Mate £20, Chief Petty Officer £20, £16 to each of the four Petty Officers, £8 to each of the four Able Bodied Seamen, £6 each to the two Deckhands, two Engine Hands and the Coal Trimmer.
The U-18 was ordered on 6 May 1910. She was built at Kaiserliche Werft Danzig and cost 2,333,000 Goldmark. She was laid down on 27 October 1910, launched on 25 April 1912 and commissioned on 17 November 1912. She was a German Type U-17 submarine with displacement 564 tons (622 short tons) surfaced and 691 tons (762 short tons) submerged. Her length was 62.35 m (204 ft 7 in), beam 6 m (19 ft 8 in), height 7.30 m (23 ft 11 in) and draught 3.40 m (11 ft 2 in). Her propulsion was through 2 shafts, driven by 2 × 2 Körting 8-cylinder two stroke paraffin motors with 1,400 PS (1,400 hp), 2 × AEG electric motors with 1,120 PS (1,100 hp), delivering 550 rpm surfaced, 425 rpm submerged. Her speed was 14.9 knots (27.6 km/h; 17.1 mph) surfaced, 9.5 knots (17.6 km/h; 10.9 mph) submerged. Her range was 6,700 nautical miles (7,700 mi; 12,400 km) at 8 kn surfaced, 75 nautical miles (86 mi; 139 km) at 5 kn submerged. Her test depth was 50 m (164 ft 1 in). She had a complement of four officers and twenty-five men. Her armament was 4 x 45 cm (17.7 in) torpedo tubes, (2 each bow and stern), with 6 torpedoes.
U-18 served as part of the German Imperial Navy II Flotilla. From 1 Aug 1914 – 23 Nov 1914 she was commanded by Kptlt Heinrich von Henning and from 1 Aug 1914 – 23 Nov 1914 she undertook three patrols, but had no victories.
The wreck of the U-18 now lies in a depth of around 70m at possible position 58.42.128N, 02.48.08W. She lies in a trough between sand waves and is a difficult dive due to the strong tides of the Pentland Firth The wreck is remarkably intact, standing upright with the deck plating rotted through and a large gouge at the stern where the ramming took place.