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Ted Arnold

WSTG 1964-1970: The Underwater Group “U” Section

This is a brief account of a short period of WSTG’s Underwater Section’s history.  It only covers the Surface Sonar’s.  Detailed descriptions of the Weapons side of underwater warfare, such as Sonar 170, Mortar Mk 10, and STWS 2 etc have not been given.  Submarine Sonar’s or Torpedo weapon Systems, have also been left out as I had no experience in that field.  Perhaps WSTG members who worked in these areas might like to contribute an article for the web site.

I first became aware of the existence of WSTG when Michael (Mick) Lawson visited HM Dockyard Chatham in 1962.  I was an Inspector of Electrical fitters (afloat) looking after the Chatham based squadron of Coastal Minesweepers (CMS).  Several were undergoing conversion of the main engines and generators, from Mirlees to Deltic diesel engines.  As the ship’s magnetic fields were altered by the change, additional Degaussing coils were added to overcome the changes to the ships magnetic signature.  On completion of their conversion they were taken to the degaussing range where the current through their degaussing coils was adjusted to give a minimum magnetic signature.

HMS Bronington a CMS had arrived one Friday afternoon and was immediately docked and a large canvas screen placed around the ship.  We were told that this was a bit of a hush hush job. I subsequently found out that HMS Bronington had been fitted with an early production model of the mine hunting Sonar 193.  She had a problem with her active rudders and leaks in one or more of her sonar cables from the hull outfit to the cabinets in the Sonar Control room.  Mick had been sent up to examine the problem and provide a solution.

He was soon making soothing noises to the captain who was desperate to get the equipment fixed and be on his way to a NATO exercise.  We discussed the problems and the available time scale to repair the active rudder.  A new electric motor was required to replace the defective one and Mike ordered one up from the stores held in Portland.  As Mick had arrived from Portland, I had assumed that he was a scientist, but he soon explained that he was a Grade B Technical Officer with WSTG.  This was hard to believe as he was actually getting his hands dirty as a senior Foreman!  In the 60’s foremen (Technical Grade 1) lived in big offices and were to be respected and here was a senior foreman actually at the coal face.

By 1964 I had moved from refits on Destroyers, Daring class, Battle class etc and had been transferred to the newly created Planning Department.  My job was to take the refit plan, containing the Defect lists and Alterations and Additions (A’s and A’s) and produce work sheets giving details of all the cost centres involved in the task, to ensure that the future refits on Destroyers would be completed to time and cost.

A few months into this task I was a little bit bored as this was my first introduction to large amounts of paper work, miles away from the front end of any action.  I am the first to admit that I was quite young and lacking in the desire to become familiar with Management Techniques.

During the summer several vacancies for Technical Grade 1 officers with WSTG were promulgated in Admiralty Fleet Orders (AFO’s.)  So I duly applied for a post and was successful.  In September of that year I left HM Dockyard Chatham for HM Dockyard Portsmouth, Staff Officers Mess, and WSTG’s temporary offices.

During my National Service with REME I had been trained in Radar techniques and became a Radar Instructor and so naturally assumed that I would be allocated to the Radar section.  Wrong, I was seconded to the underwater group, under Don Warren.

Periods of training followed at RNSD Copenacre where the Production Department’s test group set to work (STW) equipment prior to installation at the Shipyards.  John Mills was my mentor on sonar 170.  This was the attack sonar that controlled the Mortar Mk 10 at the stern of the numerous classes of anti submarine Frigates.  The sonar was able to give both bearing and depth of a target, to an analogue computer for the deployment of the mortars, which would then fire a pattern of three mortar rounds which straddled the target before exploding at different depths.

In November the whole of the Underwater team were sent to Yarrows Shipyard in Glasgow, to HMS Naiad, (Batch 1 Leander).  I was given the task, as part of a team to STW Sonar177 the Search sonar and having looked at some of the appropriate BR’s prior to the trip, became familiar with the real equipment.  I was grateful to be able to call on the experience of Bill Hole, Colin Hare and others during this makie learnie period.  The underwater team also set to work the following equipments:-

Sonar Outfits

1.162, Sideways looking sonar for submarine classification

2.170, Attack sonar associated with the Mortar Mk 10

3.176, Hydrophone Effect sonar for classifying targets and sonar bearings

4.177, Main search and detection sonar

5.765, Echo sounder to provide depth below the ship

6.185   Underwater telephone

The sonar equipments were housed in different locations, the Hull Outfits, the Sonar Instrument space (SIS), the Sonar Control room (SCR), the Operations room (OR) and the Bridge.

The transducers for the main sonar’s were housed in two Hull outfits HO 18 and 19.  The hull outfits were made from stainless steel and were mounted forward of the Sonar Instrument space.  They were free flooding and this allowed the sonar beams created in the transducer, to pass through the structures to the sea with minimum loss of power.  There was also a monitor transducer ahead of both HO’s to enable the power from the transducers to be monitored and beam patterns emanating from the system to be taken for evaluation.

In Type 177 the transfer of energy by the transducer was known as magnetostriction, as the transducer was constructed from a large number of individual laminated elements.  Transducers convert electrical energy into mechanical (kinetic) energy which then propagates through the water as a longitudinal Sound pressure wave. This process is known as acoustic transduction, and is a two-way process.  The Transmitter converts electrical energy to mechanical energy via the transducer and a longitudinal pressure wave is produced and emitted.  If the sound wave strikes a target, sound energy is reflected back to the transducer and the reverse process takes place.  Mechanical energy is converted to electrical energy and processed by the receivers in the electronic equipment.  The time taken from transmission of the pulse to its reception can be interpolated to give the range of the target.  The range could be read directly on a Range Recorder fitted in the SCR.  Adjacent CRT’s could also confirm the range and if the target was moving the Doppler Display would give its speed and direction.  The Sector display would indicate the bearing of the target.  This information was given to the Sonar 170 and if the sonar controller considered the target a threat, action would commence.

The main problem with the sonar 177 equipment was the large rectangular transducers (approximately 2 tons in weight) which occasionally broke down. This was caused by the breakdown in the electrical cable insulation, within an individual transducer element.  As the cables were subjected to several thousand volts via the transmitter and were totally immersed in sea water, the HT fuses would blow and the transmitter would have to be shut down. Urgent action was required to repair the damage.  The Hull Outfit’s dome had to be sealed to the ships hull, to ensure it was watertight.  The large cover plate then had to be removed placed to one side and then the transducer was raised by a winch for repair.  Changing a defective element once it had been located, took quite a long time, as the spare transducer had to be soaked overnight in a trough of clean water before the coil insulation could be HV tested for any electrical defects prior to being fitted.  The new transducer element or elements were fitted within the stack and numerous cables were then resealed.  This process used a special portable heat gun to melt the cable’s insulation and cover the joint with additional melted polythene type insulation.  The transducer was then retested prior to being lowered into the HO and the cover plate replaced.

This was probably the worst task that had to be performed on the whole equipment as besides being labour intensive, all sorts of unpleasant sewerage came up with the transducer. The environment has improved over the last forty years, due to the European Union rules and regulations, therefore working on transducers in Portsmouth harbour, I am sure would not be so unpleasant, or unhygienic!

Several more trips to STW at the shipyard followed before the Ship sailed to a southern port after a Final Installation Inspection (FII) for further periods of STW and final tuning before trials were undertaken on the equipment, by an independent Group of Naval Officers from Captain Weapons Trials (CWT).

 After Harbour Acceptance Trials (H A T’s) carried out by (CWT), Sea Acceptance Trials (S A T’s) followed.  Normally the team were on board very early as the ship had to travel some distance off the Isle of Wight or down to Portland to pick up a target submarine, if we were lucky.

During the winter periods many a good breakfast or lunch went over the side due to rough weather.  Mal de mer seemed to affect some of the team members worse than others.  Different varieties of sick sickness tablets were tried but the most effective ones left you fairly drowsy and that was not very helpful if you had to adjust Doppler filters in the SIS, or the Power Amplifiers for the transducer.  It seemed worse if you could not see the horizon to obtain some stabilization.  A metal waste paper basket was always helpful, whilst the trials officer asked you to tweak a filter up or down.

At a suitable time the ship would head back to base to return the trials team to shore.

Frequently the Ships Captain would save time and fuel by not going back into harbour overnight and would send for a liberty boat.  Transfer at sea to a trawler size Port Auxiliary Service craft (MFV) after a day at sea, was another experience.  Each individual team member had to climb down a Jacobs’s ladder flung over the side of the ship.  This was late at night, in the dark and you had to step off the ladder onto the heaving deck of the MFV.  Needless to say this required excellent timing, before you let go of the ladder.  If the sea was really rough, (Force 6 +), the PAS boat frequently passed you on the way up, as you were clinging to the ladder, on the way down.

The following morning the team would assemble early in the Dockyard for a repeat performance, when the teams were returned to the trials ship via the MFV (Motorised Fishing Vessel?).  This was expected of all the members of WSTG trials teams’ wither on Radar, Gunnery, Communications or Sonar.  Health and Safety conditions had not yet been applied to this section of the Civil Service!

This process would continue until the CWT team was satisfied that the equipment was operating satisfactorily.  A Wash up meeting chaired by CWT with Ships staff and WSTG representatives in attendance would then take place on board. During the meeting CWT raised and listed any problems that needed explanation or rectification, before the equipment was officially handed over to the ships staff to maintain.

Setting to work was undertaken all over the country as the number of Leander Class Frigates was quite large, 26 in total, divided into Batch 1’s, Batch 2,s and Batch 3’s. There were also another two built for the Royal New Zealand Navy, HMNZS Waikato and HMNZS Canterbury.  The County Class Destroyers HMS Fife Glamorgan, Kent etc also needed their Weapon equipments attended to and so the teams were kept busy, with STW and trials on the original equipments, modifications in the Royal Dockyards and assisting with the fitting of new underwater outfits such as:-

1.Sonar 184 Search Sonar To replace Sonar 177

2.Sonar 199 Variable Depth Sonar and Towed vehicle

3.Sonar Type 182 Towed Decoys

4.IKARA Anti Submarine Missile System

5.On board Training Aids

Another task allocated to WSTG was the responsibility for the First Fit of any weapon equipment in any of the Royal Dockyards, including Gibraltar.  WSTG also assisted D/Sales with the Installations, STW etc of weapon equipment sold to a Commonwealth or foreign Government.

My first encounter with foreign sales was the STW and Trials on six Peruvian Patrol boats built in Vosper’s in Portchester. They were fitted with Sonar 147/163 developed during WW2 to track and destroy enemy submarines.  The equipment was fitted into a small rack in a compartment and Electrical power was fed to a circular Quartz Transducer which was lowered by rope from within the sonar room, when the ship was underway.  If you have seen the film the Cruel Sea, this was the equipment that provided the Ping and referred to as ASDIC. (Anti Submarine Detection Investigation Committee).

The equipment was a thermionic valve system and was quite easy to tune, once you had established the resonant frequency of the transducer.  The only difficulty was to try to explain to the Peruvians, that the transducers each had different frequencies.  The Vosper shipyard was in old Portsmouth, where some very expensive housing now stands.  When the tide went out the harbour was just silt and the ships rested on the mud.  So every night before low tide the crew had to recover the transducers, by lowering them out of the ship, then raising them on to the deck, by rope, which was in the form of a large loop and place them on the dockside.  The next morning the transducer that was closest to their particular ship would be fitted, since they all looked alike.  It was sometimes necessary to retune the system using several different frequencies until the system responded. This caught out CWT’s officers who were not aware of the swapping of the transducers and intended to fail the SAT until the set was retuned.  We had to indelibly mark the individual transducer with the ships name, before the Peruvians responded.

My next trip with D/Sales was to Kiel to set to work Sonar 162 in a German Minelayer!  I won’t go into the journey to Kiel but the assurance by my bosses that everyone in Germany spoke English was a slight exaggeration.  Using the Hamburg underground was another new experience as I had to get to Altona Main railway station from the city centre.  Taxis were frowned upon, so public transport was the order of the day.  Eventually arriving in Kiel, I was met at the hotel and taken to the shipyard to do an installation inspection, prior to STW.

I was asked to examine the equipment and to install the three transducers in their respective housings.  One was keel mounted and the other two were fitted on the starboard and port side of the ship below the water line.  The three strip transducers can be switched to produce a fan shaped sonar beam to the starboard or port side of the ship.  This produces contours of the sea bed immediately below and to the side of the ship.

The Type 162 operates at 50 kHz and is designed to detect submarines or other debris on the ocean floor.  A shadow type picture of the sea bed was produced on chemically treated paper, by the recorder which was fitted on the bridge, alongside their Echo sounder.  The recorder also acts as a switching unit for the system.

The ship sailed down the Kiel Canal on her way to Wilhelmshaven.  This water way joins the Baltic Sea to the North Sea without having to sail around Denmark.  The 162 gave excellent contours of the canal but the Captain insisted on going to Heligoland for a few days prior to sailing for Wilhelmshaven.  He seemed quite happy with the equipment and their representatives accepted the system.  I eventually caught a train back to Hamburg and a flight home.

Visits to several Shipbuilders over the next few years to set to work had some significance, as the ships were to be the last built in that yard.  J Samuel White in the Isle of Wight at Cowes saw an urgent need by the shipbuilder, to move the ship before the new Employment law came into effect.  The law forced employers to pay redundancy pay to their employees, based on their time served with the company. Needless to say there were some delays experienced by all our groups, but finally HMS Arethusa, not quite finished was brought into HM Naval Base Portsmouth to finish off the outstanding items, both in the weapons and ship fitting areas. I don’t remember if any compensation was paid to their employees!

We also experienced something similar in Hawthorne Leslie at Hebburn on the Tyne.  HMS Argonaut was finished without too long a delay in the Sonar area. (from memory).  Another Shipyard was Alexander Stephens on the Clyde.  This yard used a fitting out berth very close to the Glasgow Sewage works and at certain states of the tide and without any off shore winds the smell was incredibly pungent.  You had to run to the ship, HMS Hermione from the car park, otherwise you would be ill.  It is strange what memories are etched into your mind.  The ship was delayed several times with boiler trouble and other serious mechanical problems.  Incidentally she was also the last ship to leave HM Dockyard Chatham in 1982 when she was converted to take GWS 25 Sea wolf.

There were several little rush jobs that had to be undertaken by everyone; sometimes you drew the short straw.  I was rushed over to Belfast to the Harland and Wolff shipyard as HMS Fearless was due to go on Contractors Sea Trials (CST’s) and needed her echo sounder sonar 765 and a Radar outfit 1006.  This was a mandatory requirement by the Board of Trade, before any ship was allowed to go to sea.  I was told that WSTG had only 24 hours to clear the problem as she had to go on CST’s.  This was all very well but I was not familiar with Sonar 765.  The aircraft took off from HMS Daedalus, Lee on Solent, so I read the handbook or rather I tried to, on the way.  The weather was blowing a gale and raining, so I took a dim view of my first trip to Belfast.  The date was the 11th July so on the 12th July 1965 which was a Friday, after eating a “Belfast Fry” under the landlady’s beady eye; I was taken to the shipyard through the marching bands.  The problem was an incorrectly connected mains transformer supplying power to the set.  The ship sailed on time and the ship was put through its paces.  I was eventually dropped off at the tail of the bank in Scotland at midnight and managed to hitch a lift with a contractor and eventually found a hotel in Glasgow.  I flew back to London the following morning.

I was tasked with STW HMS Sirius Sonar 184 in Portsmouth Naval Base in 1966.  This was a first fit of the sonar in the base.  The sonar differed from the Sonar 177 as it had a circular transducer and could also produce a ripple mode when transmitting.  The Type 184 has a circular 1.2m diameter 32-stave transducer and operated at low frequencies.  This produces up to four beams, creating a 45 degree "searchlight arc" and the display system, which had a torpedo-warning capability, and could automatically track two targets at once.

The transducer was easier to repair as it did not involve melting the polythene type cable, but simply inserting a plug with a lead at the top end of the individual transducer stave. The transducer used quartz as the elements in 32 stainless steel staves.  We were also asked to prove the accuracy of the handbooks and feed the errors to the Technical Publications officers for rectification.  There were quite a few in the draft copies originally supplied so these were marked up and forwarded to the Technical Publications section and Graseby’s.

All seemed to go well until the beam patterns were taken and a large unknown peak appeared in the records.  We contacted Portland for advice and we were told that an investigation would have to take place in Portland Naval Base.  The ship sailed to Portland and after some detailed investigation with the dome removed, the scientists found that there was a reflection within the dome at the sonar’s particular frequency. The ship returned to Portsmouth on a Friday afternoon for SAT’s on Monday morning.  Unfortunately as everything had been tweaked during the investigation, it meant the weekend was spent on board with ship’s staff, retuning the system. The ship passed her acceptance trials and we were invited back for cocktails!  Incidentally I met a young apprentice on board HMS Sirius who seemed quite keen.  He later joined WSTG and is now your Web Master, Adrian

 Shortly after this we were asked to go to Belfast, as the next ship the HMNZS Waikato (another D/Sales commission) was nearly ready to commence her (II) at Harland and Wolff.  So the team went over and checked the Installation and started STW the Sonar systems.  The ship was fitted with sonar 177M as the main search sonar, so it was back to some transducer problems.  The rest of the equipments were similar to a standard Leander.

It was slightly strange setting to work in Harland and Wolff, as the ship seemed to have two individual teams of electricians, one forward and one aft.  They did not appear to communicate very well, we decided not to rock the boat, so when there was a problem with ships wiring, we asked the team involved in that area of the ship.

 We worked well with the New Zealand crew and met socially.  Unfortunately the sonar CPO was killed on Eastern Road just before Christmas 1966.  The transducer true to form had to be raised when the ship came to Portsmouth to undergo her acceptance trials.  These were successful although the Mortar team were flooded out when the ship went full astern with the sonar and mortar room doors open.  My first introduction to the properties of WD 40!

 There were other ships requiring our time and we assisted other team leaders with STW and trials on HMS Juno built in John Thornycroft’s shipyard in Southampton.

I was then asked to go to STW HMS Kepple in Gibraltar in March 1967.  This was a conversion of a Type 14 Frigate to install Sonar 177M.

 This was a really enjoyable trip with warm sunny periods and meeting up with old friends from Chatham.  They arranged trips into Spain and Tangiers and later on an organised trip to the Alhambra.  The hotels on the main road were extremely noisy especially when cruise liners came to visit.  When the tourists arrived the price of all the goods in the shops went up, but miraculously came down after they had left!

 The Straights of Gibraltar proved to be amazing with Thermo clines that had to be seen to be believed.  The ship had a disposable bathythermograph which was released via a tube over the ships side and measured the sea temperature on the way down to the bottom.  This was fed to a recorder to give sonar conditions for the day.  We went out on SAT’s and had a submarine available but with the bad conditions due to the thermo clines we could not track the sub at any great distance.  By the afternoon conditions had changed and the sonar was tracked at over 10 000 yards. So the CWT team were happy and the sonar was accepted.