The Battle of Jutland and its Communicators

(with reference to other Communicators in much later times)

Written by Godfrey Dykes

© RN Communications Branch Museum/Library

HMS IRON DUKE - a Super Dreadnought battleship - Flagship of Admiral Sir John Rushworth Jellicoe

  Interesting to note the Training of Communicators in 1912 and the numbers and venue's involved.
  (a). The venue's were HMS Vernon (Portsmouth), HMS Defiance (Devonport) and HMS Actaeon (Chatham).
  (b). The numbers alongside course participants reflect totals and not length of course.
  (c). Marines and Lieutenant (T)/Gunners (T) which were warrant officers = Torpedoes, figured large at the various signal schools. Torpedo Branch personnel were the electrical officers/ratings of the day and therefore the 'professional' maintainers. Even in the 1960's in submarines (and possibly elsewhere although I cannot vouch for that) petty officer electricians were called POLTO's. This was the norm but most unusual, for a LTO was the rate title for a Leading Torpedo Operator (ergo also an electrician) and when promoted to the senior rates mess, the addition of PO was added to his existing title. However, on the maintenance side, operators were taught how to do routine maintenance on certain equipments and as such became departmental 'assigned maintainers', with the Chief and Petty Officer Telegraphists quite adept at keeping the show on the road without recourse to calling in the 'professionals'. Many years later in 1947, many senior telegraphists left the communications branch to help form the new electrical branch based on HMS Collingwood.
   (d). Marine Officers were commonly appointed as the ship's communications officer (SCO) meaning W/T, though marines other ranks were rarely if at all, trained or employed as telegraphists.

  This picture of the staff of R.N. W/T Station 'Rinella' Malta, shows a division of R.N., wireless telegraphy operators and their R.M., boss during the period 1912 to 1916. Note the badges and the white tropical rig (Number 6's) are almost identical to what we wore 50 (and more) years later except that is for the CPO Telegraphist (3rd from left middle) who wears his black W/T branch badge on his right cuff instead of a blue badge. Note also the two dogs and the odd-man-out?, the PO on the right front seated wearing black socks - shocking!

  This photograph has a significance with the Battle of Jutland and in particular for those in charge (although dramatically fewer) of the W/T Communications Branch of the Flag Ship HMS Iron Duke. Note in 1914 RN officers who qualified as Signals Officers gaining the symbol (S) alongside their names in the Navy List, did not quialify in wireless telegraphy. That was the remit of RM officers only at that time. The 'dagger' symbol was used for many branches/specialities but not signals officers.

  Iron Duke commissioned as a new build on the 10th March 1914 in Portsmouth as the Home Fleet Flag Ship (her radio callsign was GSDK, phonetically George Sugar Charlie King) with the Flag of Admiral Sir George Callagham. His Flag Lieutenant was Herbert Fitzherbert by the time of commissioning an old and bold lieutenant RN (seniority 1907), qualified as an (S) officer.

  With him were the ships communicators:
  Lt Cdr Everard J Hardman-Jones RN (S)
  Lt William D Phipps RN (S)
  Captain Bernard C Gardiner RM (Instructor in W/T).
  Signal Boatswain Frederick Well - Warrant Officer
  Signal Boatswain Herbert J Harvey - Warrant Officer
  Warrant Telegraphist Harry Simpson.

  Reading between the lines, there is a tale to be told, that being, all but one of the RN senior communicators WERE NOT QUALIFIED IN W/T and the only commissioned officer on board so qualified, was a junior Royal Marine officer. By 1914 W/T had advanced tremendously and all ships were fitted, with many local shore W/T stations and long distance W/T stations functioning and taking traffic: certainly, the Iron Duke herself was well equipped with W/T equipment. It begs a question here. It almost looks as though the Admiralty had appointed communicators of yore, to fight the ship and the fleet in the Pasco fashion as at Trafalgar!

  By this time August 1914, Callaghan had been the C-in-C since 1911 and was now an old man aged 62. After flying his Flag in Iron Duke for just a few months and with the ever darkening storms clouds gathering, Churchill wanted a younger C-in-C and to Callaghan's heart-break, chose Acting Admiral John Rushworth Jellicoe (later post nominals KCB KCVO). Just before war did break out in August, Jellicoe had travelled to Scapa Flow there to meet the Iron Duke on her arrival back in her base. The two admirals shook hands and said their goodbye's and Jellicoe was grateful to Callaghan for turning over an efficient Fleet, engineered that way by Callaghan's efforts. Eventually, as we know, both men were promoted to the rank of Admiral of the Fleet.

  With Admiral Jellicoe came a whole new organisation on the communications front, a team who could and did address both the V/S and the W/T side of the department. It is as though the Admiralty had taken heed of the saying: Of what avail the loaded tube?; the cannon and the shell?; if Flags and W/T default, the Fleet will go to hell. and even with both sub departments firing on all systems. we very nearly did!

  Jellicoe brought with him two commanders, one Richard L Nicholson RN (for W/T duties) and Alexander Riall Wadham Woods RN ( a specialist German interpreter - for V/S duties), Captain RM Francis W Home to replace Capt RM Gardiner (both for W/T duties). All other communicators listed above remained.

  Jellicoe showed his appreciation to the communicators in his dispatches recommending honours and awards. He tasked his subordinate admirals, commodores and senior captains to do the same.

  Quite surprisingly the old and bold Flag Lt, Herbert Fitzherbert, stayed on board the Iron Duke albeit with a sideways move from Flag Lt to Flag Lt for the 'war services' department and was promoted in-situ to Lt Cdr (S), but unlike so many of his peers, finished Jutland with a “Commendation for his Services”. Others, as you will read, were given high honours and awards.

  The new communications crew resulted in a major shift having two Commanders in charge, one for V/S and one for W/T. Their names respectively were Commander Alexander Riall Wadham Woods RN and Commander Richard Lindsay Nicholson RN. Admiral Jellicoe rewarded each with a DSO saying that each had with great coolness and most marked efficiency reaped the rewards that the organisations they were in charge of richly deserved.

  This of course can only mean that the staff/flag and ship did fully use the W/T systems on board, almost contrary to what history tells us!

  There were many very senior officers embarked in Iron Duke, but equally many umpteen more in the British Fleet. Jellicoe was most generous in thanking all, tasking each subordinate flag officer to put forward recommendations for honours and awards, and the following list shows how the communicators were rewarded after the 1st June 1916.

  In no specific order they were:-
  Lt Cdr Henry Ruthven Moore (S) Flag Lt DSO via Commodore James R P Hawkesley
  Lt Cdr James Buller Kitson (S) DSO Flag Lt Admiral Sir Cecil Burney
  Lt Cdr Ralph Frederick Seymour (S) DSO Flag Lt to Admiral Beatty
  Lt Arthur Malcolm Peters (S) DSC on Admiral Beatty’s recommendation
  Lt Cdr David Norman Walter Joel (S) Flag Lt - Commendation for his services
  Lt Cdr Alfred Englefield Evans (S) Flag Lt – Commendation for his services
  Lt Cdr Martin Edward Scobell Boissier (S) Flag Lt - Commendation for his services.
  Lt Cdr Philip Acheson Warre (S) Flag Lt – Commendation for his services
  Lt Thefton Humphrey Legge (S) Flag Lt – Commendation for his services
  Lt Stewart Dykes Spicer (S) Flag Lt – Commendation for his services

  Officers recommended for early promotion - Ralph Frederick Seymour

  Many of the fleets, chief warrant officers and warrant officers were rewarded for their services in the Battle, largely being given promotions to lieutenant or early promotion when available to the next rank/rating. This was extended to the lower deck down to as far as petty officers, some of whom were granted rapid promotion to either WO or even direct to the Mate rank, a sub lieutenant , thereby fast tracked to what we later called the general list.

  There were no MID’s at that time although the commendation was recorded and considered the same type of reward for war service.

  Additionally were:
  Captain Richmond Campbell Shakespear Waller, R.M.L.I. upon whom Vice-Admiral Sir Doveton Sturdee reports:
  " This officer has served continuously in the Home and Grand Fleet from April, 1913, and has been in charge of the wireless organisation of a Battle Squadron since the commencement of hostilities. This squadron was composed of new ships of various types which had been hurriedly completed and the work entailed in bringing the wireless installations of ships designed for foreign powers' into effective working order was carried out entirely satisfactorily. His unceasing endeavours to improve the wireless of the squadron, has been of valuable assistance since I have been in command; an excellent Marine Officer."

  Indicative that W/T was used, again contrary to several reports otherwise!

  Lieutenant Harold Marsland Franks, R.M.A.upon whom Vice-Admiral Sir David Beatty reports:
W/T Officer on my Staff. Showed great skill and resource in maintaining the vitally important wireless communications throughout the action, despite the fact that aerials were shot away and required constant repair. An officer of high technical skill."

  Yet again a leading protagonist of the battle salutes the W/T department ! Signal Boatswains. Ernest Albert Dunk Collins upon whom Admiral Sir Cecil Burney reports: —
Rendered excellent service during the action in charge of the signal staff, and also, after the transfer of my flag, reorganised the signal staff very quickly into one suitable for a flagship.

  Warrant Telegraphist. Samuel Lewington. Was in charge of the auxiliary W/T cabinet during the whole, operations, and carried out his work with conspicuous coolness and ability.

  Lieutenant RNVR William F Cleveland Stevens. For good organisation of W/T department.

  Signal Boatswain Harry Albert Pitt, Signal Boatswain Ernest Albert Dunk Collins, Signal Boatswain John Joseph Gowen and Warrant Telegraphist Samuel Lewington all received high recommends.

  Promotions to be made on the strength of Jutland service - Signal Boatswain Harry Albert Pitt - Signal Boatswain Ernest Albert Dunk Collins - Signal Boatswain John Joseph Gowen - Warrant Telegraphist Samuel Lewington.

  The President of the French Republic has bestowed the " Medaille Militaire," with the approval of His Majesty the King, on the undermentioned Commissioned Warrant Officers, Warrant Officers, Petty Officers and Men in recognition of their services during the war: —
  Signal Boatswain George Hollister, R.N.
  Warrant Telegraphist (Act.) 'Wilfred Smallr. R.N.
  Warrant Telegraphist (tempy.) George Ackroyd, R.N.R.
  Chief Yeoman of Signals Frank Rogerson, O.N. 204082.
  Chief Yeoman of Signals Samuel Alfred Brooks, O.N. 202192.
  Chief Yeoman of Signals Robert W. Garon, R.F.R., O.N. 140347.
  Chief Petty Officer Telegraphist John Cox,. O.N. 196852.
  Chief Petty Officer Telegraphist Patrick McEvoy, O.N. 173198.
  Petty Officer Telegraphist Robert Taylor, O.N, 239893.
  Leading Signalman Charles H. King, O.N. J.4428.
  Leading Signalman Albert Edward Martin (R.F.R.), O.N. 205596, R.F.R. (B) 1773 Portsmouth.
  Yeoman of Signals William Henry White, O.N. 224985.

   Returning to the picture above 1912-1916 W/T staff - as for the black arm band, a sign of national mourning, I cannot find a Royal high profile death in this period. With sarcasm as my lead, he might have been lamenting that he wasn't in on the major Marconi scandal of 1912 at a time when he could have become rich.

  The Marconi scandal was a British political scandal that broke in the summer of 1912. It centred on allegations that highly placed members of the Liberal government, under H. H. Asquith as Prime Minister, had profited by improper use of information about the Government's intentions with respect to the Marconi Company: knowing that the government was about to issue a lucrative contract to the British Marconi company for the Imperial Wireless Chain, they had bought shares in an American subsidiary.

  The political consequences were in fact slight, but the group around the New Witness drew conclusions about corruption in British politics, which were to resonate for 25 years.

  This picture dates from 1918-1919 and it too has an oddity? Note all the lower deck personnel wearing their WW1 medals but not the two commissioned officers - strange! However, they are both leaning on sticks (walking sticks) instead of on swords so they were clearly not in their ceremonial rig. Note the badge of the PO seated right middle row. He wears crossed torpedoes which was the badge at that time of what became our "greenies", our equipment maintainers. Again, a Marines officer in charge.

  Where that was the case, a small letter 'S' would shown alongside his name. Were the officer to become a deep specialist in communications he would be shown in the seniority columns of the Navy List with a larger bold letter S within a circle. It was usual that a Lieutenant R.N., (S) was a specialist in (at that time) signalling of yore, and not in wireless telegraphy. He was therefore an expert in fleet dispositions, manoeuvres, flag-signalling, semaphore, flashing light, heliographs and was the captains right hand man in the preparation for a shooting match. His fame was to come four years later at the Battle of Jutland and the famous signal "Equal Speed Charlie London". Come the end of WW1, and in the light of the conduct of the war, the officers system changed. A couple of years after the system below was adopted, RM officers were no longer appointed to ships although the practice continued to appoint to shore wireless stations. However, that too was to peter out in the years that followed, when the SWS (Shore Wireless Service) and the SSS (Shore Signal Service) were inaugurated in late 1925.

The SWS and the SSS badge had an equivalent RN rating and officer structure. This table shows only the SWS system, but it applied to the SSS also. Their titles were as per the left hand column. When with the navy they were saluted and called 'sir' as though they were naval officers proper. From 1949 until 1956 officers stripes were, from top to bottom right hand column 1 x ¼" stripe; 1 x ½" stripe and 2 x ½" stripes.

RN Shore Wireless Service

Rank		Relative Naval Rank
Chief Officer		Commissioned Officer (Branch List)
Senior Chief Officer		Senior Commissioned Officer (Branch List)
Lieutenant (Shore Wireless Service)		Lieutenant (Branch List)

  The SWS manned and controlled major W/T communication centres relieving regular W/T operators for sea duty. In the same vein, regular signalmen, who hitherto had manned shore MSO's (Main Signals Offices) usually found in the main dockyards where ships alongside sent the ship's duty signalman ashore to get the hand messages at times throughout the day, and V/S port services (voice, semaphore, flags and flashing light) were relieved by signal men from the SSS. Both the SWS and the SSS had ex WRENS (and other females) and a high profile on-line, manifest with this lovely page RNSSS and this Peoples War.

  In 1943, the first of naval/SWS telegraphists operators arrived at the GPO station Burnham W/T from the RN station at Flowerdown to help cope with the huge influx of W/T traffic from ships at sea. Their numbers increased and were the back-bone of naval traffic being passed to the Admiralty through this civilian station. For most of my career (1953-1983) I worked Portishead radio from many foreign stations, from submarines and ships, an organisation which included the Commonwealth ship-shore organisation including all the worlds major W/T receiving stations including Malta, Simons Town, Halifax, Vancouver, Welisara, Canberra, Darwin, Sydney, Irrirangi, Awarua, Hong Kong, Singapore, Vishakhapatnam, Chittagong, Mauritius, Karachi and Bombay.

  When the SWS/SSS system was withdrawn, all appointments to shore W/T stations were given to the RN radio electrical branch officers, and for shore communication centres, to the RN communications branch officers virtually always a Branch/Special Duties List officer.

(d) (i) - In came the dagger which symbolised a high achiever in course results, and S in brackets with two daggers meant an officer qualified in both V/S and W/T on the highest pay.
(d) (ii) - An S in brackets with one dagger meant qualified in both V/S and W/T.
(d) (iii) - In a ship - an S in brackets means an officer qualified in V/S and W/T performing those duties in that ship.
(d) (iv) - An S not in brackets means a Mate (a sub lieutenant) qualified in V/S.
(d) (v) - A W/T not in brackets means a Mate (a sub lieutenant) qualified in W/T

(S††)		In the Seniority List an Officer who is qualified in both Signalling and Wireless Telegraphy Duties and who is qualified to receive the highest rate of pay under the terms of Weekly Order 1685/1918.
(S†)		In the Seniority List an Officer who is qualified in both Signalling and Wireless Telegraphy Duties.
(S)		In a ship, an Officer qualified as above who is performing thes Duties.
S		In the Seniority List a Mate who is specially qualified in Signalling Duties. In a ship, a Mate qualified as above who is performing these Duties.
W/T		In the Seniority List a Mate who is pecially qualified in Wireless Telegraphy Duties. In a ship, a Mate qualified as above who is performing these Duties.

  In the 1930's some of that changed again and we entered WW2 with the following ranks. These remained extant until 1949.
d (vi) - Lieutenant Telegraphist
d (vii) - Signal Lieutenant

  WW2 continued a practice used in WW1 of each Fleet having embarked in its flagship a FWO and FSO (Fleet Wireless Officer) and (Fleet Signals Officer) both commanders, when the C-in-C was an admiral, and lieutenant commanders when not, and they were in the thick of it at battles like North Cape, Bismarck, Prince of Wales/Repulse, Atlantic, Admiral Cunningham in the Mediterranean, Denmark Strait, Normandy and others. Then yet another major change when the duties of the FWO and FSO were combined in the rank of commander and he became shore-bound with the overall C-in-C of that theatre/command, known as the FCO (Fleet Communications Officer) - in later days Far East Fleet where the C-in-C was called COMFEF (Commander Far East Fleet) and the Home or Western Fleet with a full-blown C-in-C WF (1967) and before that C-in-C HF (Home Fleet) . Seagoing admirals, now usually a rear admiral and exceptionally a vice admiral, still had a signals officer appointed to his staff as the flag lieutenant and much later on became known as SWO(C) - Staff Warfare Officer (Communications) and always a lieutenant commander. The ship in which the Flag was embarked had its own communication officers and rarely did the flag lieutenant interfere with his opposite number running the flagships communication.

  By the time of our last two battles involving thousands of men in many vessels which included requisitioned vessels, were fought (Suez in 1956 and Falklands in 1982) the Flag of the admiral in sea command, a vice admiral and a rear admiral respectively, things were changing with the C-in-C ashore much more aware of what was happening at sea and in regular touch with the admiral at sea. I can speak with authority about HMS Tyne at Suez which was the unique flagship for three three-star officers all embarked in the ship for the duration, the direct equivalents of three Flags. However, since we are navy talking on a naval subject, I will mention the naval Flag, that of Vice Admiral Sir Robin Durnford-Slater who was second in command of the overall operation and the naval C-in-C afloat. In full command of the operation in the Canal Zone was a lieutenant general and in command of the air forces was an air marshal. Ashore in London was a general, the full C-in-C of the war/crisis whatever one wants to call it, although to me, if just one man dies it is a war, but here there were many.

  Incidentally, in Paris sat the French supremo and in the canal zone area were other French commanders/senior officers, oh, and not to mention a big and only battleship, the Jean Bart! I assume that Admiral Durnford-Slater had a Flag Lt and that in the normal manner he was a communicator? I don't remember his name and we in the massive communications branches on board (RN, RM, RAF, ROYAL SIGNALS, WAR CORRESPONDENTS, FRENCH NAVY AND FRENCH ARMY signallers never met or even saw him doing walk-abouts. I, and therefore I must assume many others too, saw the admirals Flag Captain, a smashing officer called Captain Charles Mills RN. Before I finish this paragraph I need to tell you that the two wars I have mentioned, Suez and Falklands, were so vastly different that there can be few comparisons.

  Having said that, the Falklands was a proper war, brilliantly executed despite the tragic losses of at least six important vessels and over 250 men, and as much as anything it was an outstanding logistic exercise which if only for the distance it covered, will probably always remain unique. It is a war we are fiercely proud of for every reason possibly. On the other hand Suez was a failure, not a military failure but a political failure engineered by the Americans, chiefly Dean Rusk Secretary of State to President Eisenhower, and supported in that endeavour by our enemies including 75% of the UK population. We came back with our tails between our legs as the Falkland boys, rightly came home as heroes. The number of ships, of all kinds was roughly three times as many as those involved in the Falklands, and again brilliantly supported but over a shorter distance by our bases in Gibraltar, Malta and Cyprus.

  The manpower was mind boggling. Not only did we have a large and strong navy in the mid-50's, but we stopped all personnel from leaving the navy (including time expired national servicemen) routinely returning to civilian life; we called up all the reservists; we even had the support in-situ of a New Zealand cruiser to add to our many cruisers present plus French cruisers- HMNZS Royalist); it was the last time that the skies over enemy territory was blackened by British paratroops - they haven't dropped since 1956; we imprisoned several high ranking Egyptian officers in Tyne's cells used normally for our own erring sailors; we acted as a major clearing station/hospital for our troops on the ground ashore who were killed or injured; and to wander around our communications compartments and offices was like being in star wars such were their sizes and complexities; and, just as at the Falklands, one of our cruisers, the Newfoundland which was patrolling the Red Sea end of the Bitter Lakes, sank an Egyptian frigate with gunfire. It is almost unbelievable therefore, when we remember that all the communications commitment the Tyne had (think of 12 war correspondents wanting their newspaper front page sent immediately and by Morse code before that of their competitor correspondents and that's before we even send one of the thousands of naval signals) was on the shoulders of one general list lieutenant (Lt Hugh Dickens RN) and 4 branch officers commissioned from the lower deck) 3 x CCO's (Commissioned Communication Officers each with 1 x ¼" stripe) and 1 x SCCO (Senior Commissioned Communications Officer with 1 x ½" stripe).

  At the end of the day, Hugh Dickens did not even get an MBE although he did get a skeletal frame (weight loss) such was the sheer stress the man lived under: in today's hand-outs he would have certainly got an OBE. Many years later when he was a commander (training commander) and I was a warrant officer (1976) we were together in the Signal School at HMS MERCURY, and we used to relive those days occasionally. I admired this man tremendously and hated the navy for not rewarding him. Mind you, because we all came out of it under a cloud , needlessly and involuntarily bowing our heads, there were no rewards for the privations suffered, the countless hours on watch, the stresses and strains and the dangers we tolerated. I end by telling you that the two men who could have met the flagship HMS Tyne on her arrival home alongside SRJ (South Railway Jetty) Portsmouth 7th January 1957 to tells us that we personally should be proud of our involvement and that we should suffer no shame, didn't bother. It was too much trouble for their comfortable lives. They of course were the First Lord of the Admiralty The Lord Hailsham and the First Sea Lord, Admiral Mountbatten.

  (e). Note the "re-qualifying" courses. Everybody in the navy, after a specified period of absence from a school (in this case a signal school), had to return to prove his skills were still relevant. It was possible to be reverted if one failed a refresher!

  (f). Short courses are self evident and were mainly acquaints to add to the overall navy/ship knowledge of officers who would not be called upon to carry out communication tasks.

  (g). Likewise courses for senior officers where a detailed acquaint and a thorough operational understanding of 1912 fleet communications was an imperative especially for commanding officers.

  (h). Scout courses were for very small ships when it would be the case that there would be only one of his specialisation on board.

  (i). Note the pairing of the Qualifying Gunner (T) and the Qualifying Warrant Telegraphists. They, in their own ways were both protagonists in the skills of wireless telegraphy, although the Gunner was a hands-on Warrant Officer with so many in the fleet, and the WO Telegraphist (with a great deal fewer in the fleet) was a manager leaving the hands-on bit to the CPO Telegraphist. He would have been appointed to large ships only, or to shore staffs.

  (j). The "other warrant officers" would have applied to the executive branches (blue jackets) = seamen, and not to engineers or the civil branches, which were much later on called the S&S Branches.

  (k). The signal schools were also responsible for teaching pure electrical skills (heavy electrics) to those deemed to be wholly electrical or pure gunnery (that is when their rate did not carry either the suffix (T) or (G).

  (l). It is probable that the two RAN course places were given to crew members of the Australian submarines AE1 and AE2 being built in the UK.

  (m). Note under training in 'Defiance' the Gunner (T) and the Gunner (G). Yes another strange rank the (G) meaning gunnery. The word Gunner simply means a warrant officer. The rationale was that guns were used much more often than torpedoes, and the electrics of gunnery were that much more complicated, huge in scale and involved than for a torpedo and its launcher, so the Gunner (T) took the extra work load of other parts of the ship in addition to torpedoes, leaving Gunner (G) to his own devices.

  (n). ST or S/T meant Sound Telegraphy (as opposed to wireless telegraphy) and was used by W/T operators to send Morse code under the sea to dived submarines or passing ships suitably fitted with transducers. Later on it was called SST. Instead of their Morse key being connected to a radio transmitter and thus to a wireless aerial array with an associated radio receiver being utilised for an incoming answer, the key was connected to the hull transducer and its aerial the diaphragm, which also acts as the receiver for the audio S/T sounds waves. Today we fully accept the concept of sound waves being used for navigation (echo sounders) for Sonar to find a dived submarine whether it be a fixed array in a prosecuting ship/submarine target, a buoy or a listening device dangling from a helicopter in the hover into the sea below, or for UWT (underwater telephony) over which normal voice communications takes place. This little diagram show the principle of using a diaphragm attached to a vessels side.

  The two sets of blocks (centre of picture) each with black strapping represent the ships side into which a hole has been cut in between them. Into that hole, offered from inside the ship on the left, the diaphragm is placed (the red device), which (with the pink coloured bolts) is then offered into the hole in the ships side and bolted taut together to form a watertight joint.

  Any man-made or natural noises (whales, dolphins etc) hits the diaphragm now perfectly flush with the rest of the ships side, which the transducer amplifies and filters out (as far as possible) other unwanted noises, passing the wanted signal to the wireless telegraphy office (silent cabinet in a pre WW1 warship) for demodulating and recording.

SWS Handbook 1927