H.M.T. TENBY CASTLE encounter with German Submarine on 6th April 1917

[JohnH]

I am researching H.M.T. TENBY CASTLE during the period 7 June 1916 to 28 August 1918 when my grandfather served on her. I have been collating a list of her crew from various records and reports which I have obtained from Kew. I have some questions about the following incident. 

On 6th April 1917, H.M.T. TENBY CASTLE in company with H.M.T. WALPOLE had an encounter with a German submarine at Lat. 58.23´N, Long. 7.43´W, some 47 nautical miles North East of the Butt Lewis on the Western Isles.  At this time, they were part of a group of 6 armed trawlers: ARLEY, ROBERT SMITH, RUSHCOE, SAXON, TENBY CASTLE and WALPOLE on the St. Kilda Patrol based out of Oban. They were part of 10th Cruiser Squadron which was based at H.M.S. GIBRALTAR at the Swarback Minns naval base on the Shetland Islands. 

The following is a report on this encounter prepared on 10 April 1917 by Sub-Lieutenant James Henry Arnold, R.N.R., who was in command of H.M. Trawler TENBY CASTLE, to Vice-Admiral Reginald G.O. Tupper Commanding 10th Cruiser Squadron: 

I have the honour to report that at 5.50 p.m. on the 6th April 1917, Lat.  58.15´N, Long. 7.59´W, approximate, steering ENE Mag. weather fine  and clear, sea smooth, whilst on patrol, in company with HMT Walpole sighted a submarine Lat. 58.20´N, Long. 7.57´W approximate, steering W.  I opened fire at extreme range, shells falling at least 500 yards short.  Submarine thereupon submerged. HMT Walpole 1 mile ahead of me meanwhile engaged another submarine who also submerged. I kept to my course and at 6.35 p.m. sighted a submarine Lat. 58.23´N, Long.  7.43´W, steering N. I immediately altered my course to port to bring my 12 PR into action, meanwhile firing with the three pounder. Shells from 3 PR falling short. The first shell from my 12 PR fired at a range of 7800 yards struck the submarine at the lower part of his conning tower. The second shell range 7750 just cleared to right of conning tower. The third shell struck submarine in practically the same place as the first shell. I  saw the submarine heel over and disappear. I ceased firing and proceeded at once to position of submarine and found surface of the water thickly coated with oil. I steamed round the oil and Walpole dropped a depth charge. Both vessels remained cruising in the vicinity of oil until 0800 7th April 1917. No further indication of the submarine being seen.

A Court of Enquiry (per ADM 137/3662) held on board H.M.S. ALSATIAN on 18 April 1917 at Swarbacks Minn, Shetland were of the opinion that the submarine had been sunk by H.M.T. TENBY CASTLE.  (I obtained a copy this Court of Enquiry from TNA and can post if necessary).

A later report from the Secretary of the Admiralty on 5 May 1917 to Vice-Admiral Tupper, Commanding 10th Cruiser Squadron considered this sinking to be be improbable.  

I am interested in finding the log book record of the German Submarine which was attacked by H.M.T. TENBY CASTLE on 6th April 1917.

We know that there were at least 4 German Submarines operating in the vicinity of the St. Kilda Patrol area during the period 5th to 7th April 1917, from records of merchant ship sinkings. 

• U57 sank the sailing vessel EBENEZER on 5 April 1917 by gunnery 10 miles SW from St. Kilda. 
• U78 sank the sailing vessel BRIS on 5 April 1917, 20 miles N of Butt of Lewis.
• U66 torpedoed the tanker POWHATAN on 6 April 1917, 25 miles NW of North Rona, Outer Hebrides.  
• U46 stopped and sunk the sailing vessel FISKAA on 7 April 1917, 10 miles off St. Kilda

Does anyone have access to German Submarine log book records for U57, U78, U66 and U46 on 6 April 1917 or know where they are located?

Thank you. 

[KizmeRD]

It can be dangerous to assume that every submarine sighting is a U-boat.

There’s also the possibility that the trawler attack as described might have accidentally involved HM Submarine E44.

MB

[Michael Lowrey]

Not all the submarines off St. Kilda were German. The British E 44 was also in the area, and was attacked by RN armed trawlers on both April 5 and 6. The Naval Staff Monograph in fact suggests the submarine Tenby Castle and Walpole attacked was E 44.

Edited 4 January , 2023 by Michael Lowrey

[KizmeRD]

Naval command would have very much appreciated the welcome news that offensive action by a hunting group of trawlers had apparently resulted in the sinking of a U-boat.
At that particular point in time, Jellicoe was under intense pressure to change his ingrained attitude towards anti-submarine defence measures, and was clutching at straws in order to come up with justifications why a universal convoy system ought not be adopted - not suggesting that may have had any influence on matters! 

MB

[JohnH]

22 minutes ago, Michael Lowrey said:

Not all the submarines off St. Kilda were German. The British E 44 was also in the area, and was attacked by RN armed trawlers on both April 5 and 6. The Naval Staff Monograph in fact suggests the submarine Tenby Castle and Walpole attacked was E 44.

I was aware of the attack on 5 April by HMT RUSHCOE on the British Sub E 44. (see attached)

Lieutenant Gilbert E. Venning, RN from the submarine E 44 was a member of the Court of Enquiry held in respect of H.M.T. TENBY CASTLE encounter with German Submarine on 6th April 1917. (see attached)

[KizmeRD]

It’s fascinating that the CO of E44 was involved in the court of enquiry, thank you for sharing that.

With the benefit of hindsight, one thing is however apparent, and that is that no U-boat was actually sunk that day. 

MB

Edited 4 January , 2023 by KizmeRD

[Simon S.]

John,

I‘ve just checked the war diaries of the four subs mentioned above. There was no encounter with armed vessels.

 

Simon

[Michael Lowrey]

Simon,

Thanks for that. In a footnote, the NSM says that:

Quote

D.S.C. to Sub Lieut. J. H. Arnold, R.N.R., Tenby Castle and £200 award. Time according to E.44 was 2.30 p.m. (H.S.627/55) and according to Tenby Castle (M.05119/17) 5.50 p.m. and 6.35 p.m. It is just possible that a German submarine may have been there for U.24, U.66, U.46, U.57 and U.59 were all on their way home at the time, but no submarine was destroyed or damaged.

Could you check U 24 or U 59, just to be safe?

[JohnH]

@Michael Lowrey Can you give me copy of the document that mentions that a £200 award was paid to Sub Lieut. J. H. Arnold, R.N.R., Tenby Castle. Thanks for your help. 

Leading Seamen John Whitley, Kinsale, County Cork, Ireland R.N.R Number: C 3642 was awarded the D.S.M. for services rendered on 6 April 1917 when he manned the 12 pounder gun on the Tenby Castle. His RNR record also states that he was paid an award for this action in Jan. 1918. No amount is detailed on his record.  He gave evidence per the Court of Enquiry on 18 April 1917 per ADM 137/3662. 

[Simon S.]

John,

neither U 24 nor U 59 reported an attack by armed guard vessels.

Simon

[Michael Lowrey]

The document is the Royal Navy’s official history, the Naval Staff Monograph, volume 18, page 460. You can download all the volumes of the NSM here (I download it a few years ago before they split vol. 18 into different parts.):  https://www.navy.gov.au/media-room/publications/wwi-naval-staff-monographs

[JohnH]

On 04/01/2023 at 20:31, Michael Lowrey said:

https://www.navy.gov.au/media-room/publications/wwi-naval-staff-monographs

@Michael Lowrey The above link to the Naval Staff Monograph, appears to be down. Do you know if the NSM is available elsewhere online. Thank you. 

[KizmeRD]

Many claims of U-boat destruction clearly don’t stand up well to close scrutiny, or to subsequent post-war analysis. Whether it was naïveté, plain wishful thinking, or deliberate overstatement is unclear, but in any case, a good number of unreliable assessments were indeed made at the time. Unfortunately exaggerated wartime claims were readily incorporated into ‘official’ publications, and so it’s not at all uncommon to see these being quoted and repeated unquestionably by somewhat undiscerning post-war authors.

MB

[JohnH]

@KizmeRD I obtained the submarine log for the E44 on the 6th April 1917. 

TNA ref ADM 173/1714.

On 6th April 1917,  the E44 records seeing two trawlers on the horizon at 2.30pm, the sub was heading South. It took evasive action and dived to 50ft at 3.00pm and didn't surface again until 10.00pm. Contrast this account with Tenby Castle account, I posted above which records this action taking place some 3 to 4 hours later on the same day. I have noted it below:

I have the honour to report that at 5.50 p.m. on the 6th April 1917, Lat.  58.15´N, Long. 7.59´W, approximate, steering ENE Mag. weather fine  and clear, sea smooth, whilst on patrol, in company with HMT Walpole sighted a submarine Lat. 58.20´N, Long. 7.57´W approximate, steering W.  I opened fire at extreme range, shells falling at least 500 yards short.  Submarine thereupon submerged. HMT Walpole 1 mile ahead of me meanwhile engaged another submarine who also submerged. I kept to my course and at 6.35 p.m. sighted a submarine Lat. 58.23´N, Long.  7.43´W, steering N.

Report on this encounter prepared on 10 April 1917 by Sub-Lieutenant James Henry Arnold, R.N.R., who was in command of H.M. Trawler TENBY CASTLE, to Vice-Admiral Reginald G.O. Tupper Commanding 10th Cruiser Squadron: 

TNA ref ADM 137/3662

[KizmeRD]

13 hours ago, KizmeRD said:

Whether it was naïveté, plain wishful thinking, or deliberate overstatement is unclear, but in any case, a good number of unreliable assessments were indeed made

The above statement certainly applies to Sub.Lt. Arnold’s written account- since it’s evident from post-war analysis that no German U-boat was ever sunk during any claimed encounter with Tenby Castle in April 1917.

It should have been disturbing that Room 40 was expressing serious concerns over many false assessments reported to them by the Anti-Submarine Division and concluded that the ASD was attempting to demonstrate a greater degree of efficiency than it was actually achieving. The temptation to overstate successes against U-boats was immense. 
 

MB

Edited 15 February by KizmeRD

[JohnH]

4 minutes ago, KizmeRD said:

The above statement certainly applies to Sub.Lt. Arnold’s written account- since it’s evident from post-war analysis that no German U-boat was ever sunk during any claimed encounter with Tenby Castle in April 1917.

The curious thing about the Court of Enquiry held into this encounter was that one of its presiding members was the commanding officer of E44, Lieutenant Gilbert E. Venning. The Court of Enquiry did find the E44 had been subject to a friendly fire incident involving the armed trawler RUSHCOE the previous day on 5th April 1917.

[The Treasurer]

4 minutes ago, JohnH said:

The curious thing about the Court of Enquiry held into this encounter was that one of its presiding members was the commanding officer of E44, Lieutenant Gilbert E. Venning. The Court of Enquiry did find the E44 had been subject to a friendly fire incident involving the armed trawler RUSHCOE the previous day on 5th April 1917.

You'll find the records of the attack in the records of X Flotilla. ADM 137/2075/8. Folio 379:

Folio 379: Number 29, 12 April 1917. E44 patrolled off St. Kilda, 3-11 April. Attacked by [RN] trawlers.

Edited 15 February by The Treasurer

[JohnH]

On 15/02/2024 at 12:15, The Treasurer said:

Folio 379: Number 29, 12 April 1917. E44 patrolled off St. Kilda, 3-11 April. Attacked by [RN] trawlers.

Here is the above report that I found at TNA Reference: ADM 137/2075/9

[The Treasurer]

32 minutes ago, JohnH said:

Here is the above report that I found at TNA Reference: ADM 137/2075/9

Interesting - thanks for sharing.

That clear's up the thing from the point of view of E.44. The point made by Captain Donaldson is a very good one. It was half-baked having a surface submarine patrol and an anti-submarine trawler patrol in the same position at the same time.

But they clearly shot at something else later on the 6th.

Edited 21 February by The Treasurer

[KizmeRD]

I’ve no not doubt that Sub.Lt. Arnold was a capable and trustworthy officer, but I am somewhat skeptical of Tenby Castle’s claimed ability in naval gunnery.

It would be surprisingly good shooting if one in ten opening shots fired from a three inch gun at a submarine conning tower 4 miles away actually hit its mark, so two out of a total of only three rounds fired hitting home is indeed remarkable - especially so without any proper range finding ability and with a manually trained gun mounting. 

Arnold was not a particularly experienced naval officer, he’d only been in the RNR five months (4 months on Tenby Castle) and he only passed his (3rd Class) gunnery certificate a few months after this event (in July 1917). This was likely his very first surface action, and in times of stress and high drama, one often sees what one seeks to believe, rather than what’s real.

MB

[JohnH]

I have attached below the complete Minutes of Evidence of the Court of Enquiry held in respect of H.M.T. TENBY CASTLE encounter with a Submarine on 6th April 1917 per TNA ref ADM 137/3662