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Seahorse (S98)

Built By: Chatham Dockyard (Medway)
Build Group: S Group 1
Fate: Mined while moving between Zones E and B in the Heligoland Bight.

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The Submarine was never heard from after sailing from Blyth on 26th December 1939 for patrol off western Jutland. Her operational area was to be initially off Heligoland then move to the mouth of the Elbe on 30 December and return to Blyth on 9th January 1940.

She was most likely sunk after being attacked and depth charged by ships from the German 1st Minesweeping Flotilla on about fifteen nautical miles north-west of Heligoland in position 54º19'N, 07º30'E.

Roll of Honour

Name Rank Number Hons Age
Armstrong, Eric  Yeoman of Signals  C/J 98393    35
Baker, John Cecil  Lieutenant      28
Bazley, Herbert George  Telegraphist  D/JX 135256    24
Cain, Arthur Percy  Able Seaman  C/JX 151568    24
Clatworthy, Ulric Wallace  Petty Officer  D/J 105929    32
Cockburn, Alexander  Warrant Engineer  (Ex.M36635    33
Coit, George Edward  Leading Stoker  C/KX 62287    35
Combe, John Jackson  Telegraphist  D/JX 134088    25
Comer, John Frederick  Leading Stoker  C/KX 82255    27
Dunwell, Jack  Leading Seaman  D/JX 134887    25
Eldridge, Walter John Edward  Leading Stoker  C/J 85635    38
CWGC has C/J 85655 the correct Service Number is C/J 85635
Eyre, Frank  Leading Seaman  D/JX 140396    21
Fleming, John Wilson  Lieutenant      25
Hines, Reginald Henry  Stoker 1st Class  D/KX 88993    22
Hyde, John Henry  Stoker 1st Class  D/KX 82154    26
Jenkinson, James Wilfred  Telegraphist  D/J 79620    37
At birth Jenkinson, James Wilfrid. Served as Jenkinson James Wilfred
Kewell, John Richard  Leading Stoker  P/KX 82275    25
Lawrenson, Desmond Robert  Engine Room Artificer 4th Class  P/MX 48910    23
Lee, Philip Stanley  Stoker Petty Officer  D/KX 79096    34
Marshall, John Edward  Stoker 1st Class  P/KX 79207    29
Massy-Dawson, Dennis Staunton  Lieutenant      30
Mayne, Richard Cecil  Able Seaman  D/JX 137405    23
Morgan, Alfred Brynmore  Leading Seaman  C/JX 137966    23
Packer, William Martin Henry  Engine Room Artificer 3rd Class  D/MX 46952    27
Perham, Donald  Stoker 1st Class  D/KX 86366    22
Phipps, Joseph Charles  Leading Stoker  P/KX 84275    26
Pughe, Arthur  Petty Officer Telegraphist  D/J 109802    31
Skilling, Albert Arthur Victor  Petty Officer  P/J 103896    35
Smith, Archibald Cyril Sayer  Engine Room Artificer 3rd Class  C/MX 47764    25
Stanton, Sydney Charles  Able Seaman  D/J 113337    31
Steventon, Alec  Leading Stoker  P/KX 84268    26
Summers, Ernest Rae Sevier  Engine Room Artificer 3rd Class  D/MX 46567    28
Thain, William  Lieutenant (RNR)     
Watson, Ernest  Stoker 1st Class  D/SS 121121    38
Wesson, Richard Raymond  Able Seaman  D/J 109893    31
Westbury, Eustace Geoffrey  Able Seaman  D/J 110045    31
White, John Henry  Petty Officer  D/J 10995    32
Wilson, Leonard James  Engine Room Artificer 4th Class  D/MX 48678    23
Windley, Harry Spencer  Able Seaman  C/JX 137778    23


14-09-1931 : Laid Down
15-11-1932 : Launched
02-10-1933 : Completed
24-08-1939 : HMS Seahorse departed Dundee to take up a patrol position to the south-west of Stavanger, Norway. When the war with Germany commenced this became her 1st war patrol.
05-09-1939 : While on the return passage to Dundee HMS Seahorse was bombed in error by a British Anson of 233 Squadron which dropped two 100lb A/S bombs. She sustained some damage which required her to dock.

Seahorse had dived when the aircraft was sighted but her after hydroplanes jammed and depth control was lost. In the meantime two depth charges were dropped by the aircraft but these caused no damage. Seahorse then broached and her bow came out of the water. A third depth charge was then dropped but this also caused no damage. Before Seahorse was able to submerge again a fourth depth charge was dropped very close which shook the submarine severely but it caused no damage. Seahorse then went down again and hit the bottom heavily at 220 feet causing damage to her A/S dome.

The aircraft had dived so low that the explosions of the bombs damaged it seriously and it had to ditch but the two airmen were rescued.
06-09-1939 : HMS Seahorse ended her 1st war patrol at Dundee but moved to Rosyth later the same day.
07-09-1939 : HMS Seahorse was docked at Rosyth.
11-09-1939 : HMS Seahorse was undocked.
12-09-1939 : HMS Seahorse moved from Rosyth to Dundee.
16-09-1939 : HMS Seahorse departed Dundee for her 2nd war patrol. She was ordered to patrol off the south-west coast of Norway.
17-09-1939 : HMS Seahorse fires four torpedoes against the German submarine U-36 in the North Sea. All torpedoes fired missed their target.
02-10-1939 : HMS Seahorse ended her 2nd war patrol at Dundee.
04-10-1939 : HMS Seahorse moved from Dundee to Rosyth where she was immediately docked.
08-10-1939 : HMS Seahorse was undocked at Rosyth and returned to Dundee.
14-10-1939 : HMS Seahorse moved from Dundee to Rosyth.
17-10-1939 : HMS Seahorse departed Rosyth for her 3rd war patrol. She was ordered to patrol off the south coast of Norway/Skagerrak.
30-10-1939 : HMS Seahorse sighted a submarine. An attack was started but before torpedoes could be fired the submarine dived. This was most likely U-21 which was patrolling in the same area but the U-boat did not observe the British submarine.
31-10-1939 : HMS Seahorse ended her 3rd war patrol at Rosyth.
09-11-1939 : HMS Seahorse departed Rosyth for Blyth.
10-11-1939 : HMS Seahorse arrived at Blyth.
12-11-1939 : HMS Seahorse departed Blyth for her 4th war patrol. She was ordered to patrol in the North Sea to the north-west of The Netherlands.
18-11-1939 : During the morning HMS Seahorse operating off Terschelling, sighted two Roeder-class destroyers but could not get in an attacking position.
28-11-1939 : HMS Seahorse ended her 4th war patrol at Blyth.
29-11-1939 : HMS Seahorse was docked at Blyth.
12-12-1939 : HMS Seahorse was undocked.
13-12-1939 : HMS Seahorse (Lt. D.S. Massy-Dawson, RN) departed Blyth for her 5th war patrol. She was ordered to patrol off the British east coast.
15-12-1939 : HMS Seahorse ended her 5th war patrol at Blyth after having been recalled.
26-12-1939 : HMS Seahorse departed Blyth for her 6th war patrol. She was ordered to patrol in the Heligoland Bight.
07-01-1940 : HMS Seahorse sunk

On 26th December 1939 HMS Seahorse sailed from Rosyth for patrol off the east coast of Denmark. Four days later she shifted position to the entrance of the Elbe. She did not return on her due date of 9th January 1940. It was first thought that she had been mined but German records, examined after the war, suggested she was the victim of the German First Minesweeper Flotilla which reported a sustained depth charge attack on an unidentified submarine on 7th January 1940.

Thanks to the research of Mr Bob Coppock of the RN Historical Branch, it is now accepted that Seahorse was mined while moving between Zones E and B in the Heligoland Bight. The wreck has been discovered off the Danish coast.


Thank you very much for putting together this information on HMS Seahorse. My uncle died on the submarine and is the last man mentioned in the submariner's list, Harry Spencer Windley, known by his family as Brian. My grandmother was devastated by his passing, he was her firstborn son, and I don’t think she ever recovered, as there was no body to bury. Thank you again.
   Carolyn McFarland Fri, 5 Feb 2021
My grandfather was on this submarine when it was lost. My dad rarely spoke of it, he was only 2yrs old when his dad was at war. I just like that I can look this up and see grand dad has been remembered somewhere. I would have loved to have met my grandfather John Henry White.
   Hannah White Sun, 19 Feb 2023

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