Weymouth's Errant Torpedoes

By Ed Cumming

What with the Navy and the Whitehead Torpedo Works at Wyke testing torpedoes in Portland Harbour & Weymouth Bay a percentage were bound (and did) go astray, despite the fitting of a 'Blowing Head' to ensure they would be recovered.  To my knowledge the number of torpedoes which have come to light in recent years must now be approaching twenty.  Most of these are currently in the Nothe Fort.  The earliest manufacture a 14" MK8 (1887) and the latest manufactured; a MK10 c.1944.  They generally tend to be found by divers or dredged up by trawlers and, so far, because they have been test torpedoes, they have not posed a serious danger to the finder.

Most torpedoes are simply encased in a thin steel tube and have four main compartments; the head, the forebody, the afterbody and the tail.  The sections are coupled together at the various bulkhead positions when the torpedo is assembled, this is achieved by body screws which are slightly inclined towards the centre line of the torpedo to enable easy access.  After a period of time in the salt water the steel shell soon starts to rot away leaving the non-ferrous components laying on the seabed like an animal skeleton devoid of its organic matter.  However on several occasions I have noticed that components of the 'forebody' i.e. the high quality nickel steel air cylinder and the balance chamber have been missing.  Following a recent incident I am now convinced there is a mechanism of decay which accounts for this.

This detail is taken from the Dorset Echo on 30th October 2006

"SKIPPER Edgar Moxam towed an unexploded torpedo he found in the sea off Portland into Weymouth Harbour. An emergency plan was put into operation and Weymouth's harbourside sealed off as experts arrived to deal with the device. Mr Moxam, 27, and his crew on the fishing boat Mojo thought the device - two feet in diameter and 15 feet long - was a telegraph pole or wooden pier pile. They brought it in amid concerns for shipping after finding it floating off the Grove on the east coast of the island. They discovered it was a Second World War British torpedo after alerting coastguards and arriving back in Weymouth at 11am. The harbour was sealed off and bomb disposal experts from the Royal Navy's Explosives and Ordnance Division (EOD) called in. They arrived at 6.15pm and found the torpedo was missing its warhead after diving into the harbour to examine the device. Police reopened the harbourside at 7.15pm after experts told officials the torpedo was missing its warhead and consisted of an air cylinder and part of a motor."

A week later:

Here the story could have ended but I just happened to be in Weymouth a week later!  An enquiry during my visit established that the errant torpedo was still in the secure area of the harbour. It had been Captain David Stabler (Weymouth's Harbourmaster) intention to have it removed for scrap but although it had been declared safe by the RNEOD, when scrap man arrived he declined to take it because there may have been residual compressed air in the air cylinder.

 

The piece of Torpedo towed in by Edgar Moxam.  The Depth Mechanism in the foreground.

Inspection of the torpedo not only confirmed that the head (probably a test head ) was indeed missing but also missing was the 'afterboy' (which housed the engine room and the buoyancy chamber) and the 'tail' section.

So following my previous observation that several of the torpedoes found on the seabed were missing this significant section, my theory for why this is, is as follows:

Once the torpedo is lost, it is not long before the thin steel shell starts to rust away.  My guess is that in most cases the 'head' rots away first.  If it is a warhead then the steel and several hundred pounds (as much as 800 pounds) of explosive soon disperses.  In the more likely event (certainly the losses around Weymouth & Portland) that it is a test head, the lead ballast added to the  head to replace the explosive, falls away from the torpedo.  In both scenarios the buoyancy of the remaining sections is significantly increased; particularly around the air cylinder.  The torpedo remains firmly seated on the seabed anchored by the significant weight of the engine room (which is normally free flooded), the buoyancy chamber and the tail section.  Perhaps due to the fact that the steel shell of the engine room is rusting from both inside and out, it is at this position that the next break occurs.  The considerable buoyancy of the air cylinder causes the forebody to finally break away from the afterbody/tail and float to the surface.  If you look at the picture above you can see that the air cylinder survived very well and was certainly still sealed and very buoyant  The balance chamber has certainly not survived as well but I know from the MK8/MK9 specification that this section was significantly stronger than the engine room and is much less likely to break away at this position.
To quote the MK8/9/10 Manuals:
"The balance chamber door is made of steel slightly doomed and secured by studs and nuts to the balance chamber bulkhead.  The door is tested to 250psi.  The door will withstand a pressure equivalent to a 300 feet head of sea water."

It is impossible to predict when this final break occurs but I am sure there will be more incidents like the one above in the very near future.

horizontal rule

I have support for this sequence of events, particularly with 21 inch MK8 & MK10 torpedoes from two other incidents which occurred in and around Portland Harbour.

The first in the late sixties involved a 21 inch, 1944, MK10 recovered from the Portland Breakwater.  Here the afterbody and tail fell away as the torpedo was lifted and were recovered. The only remains of the head was a bronze pistol and the lead ballast, the steel shell having long rotted away.  Only two components of this torpedo survive, the gyro and the counter assembly, and these are in the Nothe Fort. The forebody, which subsequently flooded, was in fact raised in 1972 by a team from the British Sub Aqua Club who gave it to the Welwyn & Hatfield Sea Cadet Corps.

The second in May 2000 involved a 1944 21" MK8, unfortunately I was unable to retrieve any components to identify its number.  This is however another very interesting saga.

Local professional divers were in Portland Harbour renewing moorings when they came across a large steel pillar sticking out of the muddy seabed.  There was little doubt that it had been there for years and also little doubt that at low spring tides it was a hazard to navigation.  The divers decided to remove it by attaching a rope to it and giving it a tug.  It was reported to me that it came away quite easily and was eventually hauled aboard their diving boat.  Their plan was to drop it well away in deep water outside the harbour. However, it was not long before the divers noticed oil leaking from it and on closer inspection felt it may be part of a torpedo.  The coastguard was informed and they were instructed to take it to Bincleaves Pier. To cut a long story short the Royal Navy's Explosives and Ordnance Division were called in and confirmed it was a torpedo.  The head & afterbody/tail were missing.

A some stage I believe this torpedo was lost from the Whitehead Pier (which used to be near Ferrybridge).  Its blowing/test head may not have had enough air for it to have floated as it was designed to do after a test run.  The torpedo, upright, sank to the seabed.  I guess the twin contra-rotating propellers may still have been turning and the torpedo dug itself a hole keeping it upright all those years.  When the divers pulled on the torpedo the afterbody and tail remained in the mud of the seabed.

The LUNAR Society rescue a little more of Weymouth's Torpedo history:

Having inspected the remaining section it was obvious that there were rare components that justified being rescued.  Firstly the depth keeping mechanism and secondly an example of a lead ballast support unit called a 'Heavy Door'.  A call to Ron Howse and David Carter resulted in the offer of assistance but we could do nothing without the permission of the Harbourmaster.  After a call to David Stabler a deal was struck.  "You can have the parts you want if you can ensure (and demonstrate) that there is no air in the cylinder so I can get the scrap yard to take it away".  Not a problem to the LUNAR team; although the air valve to the engine was in fact open, we drilled a tiny hole in the air cylinder to ensure it was indeed empty.

The Lead 'Ballast' Hatch before the clean.  This was used to identify the Torpedo

 

The writing says;

"HEAVY DOOR FOR USE WITH 'LOWING' & WAR HEADS"

For some reason the 'B' is missing from BLOWING?

[Cleaned & Photographed by Ron Howse]

 

 

The Depth Mechanism straddles the diameter of the balance chamber from top to bottom.

At the top is depth setting adjuster.  This is shown cleaned to the right.

The mechanism at the bottom is a combination of hydrostatic valve and pendulum.  The pendulum, dependant on gravity acts as a damper on the hydrostatic valve to stop the Torpedo 'Porpoising'. 

Depth Setting Control.
 

It is said that when this mechanism was invented by Robert Whitehead c. 1870 that the depth control of the torpedo was improved from ± 6 feet to ± 6 inches!

This torpedo had been set to 34 feet

[Cleaned & Photographed by Ron Howse]

 

 

Specification of the 21" MK lX & MK lX** (This if you look carefully above is a MK lX**).  It first appeared in 1930 and was considerably improved by 1939.

Date of Design

1928

Date in Service

1930

Weight

3732 lbs. (1693kg)

Overall Length 

23 ft 10.5 in (7.277 m)

Negative Buoyancy

732 lbs. (332 kg)

Explosive Charge

750 lbs. (340 kg) TNT

Engine

Burner-cycle

Power

264 hp @ 41 knots

MKlX

10,500 yards (9600 m)

36knots

13,500 yards (12,350 m

30 knots

 MKlX*  

11,000 yards (10,050 m)

36 knots

14,000 yards (12,800 m)

30 knots

MKlX** - Explosive Charge - Originally:  722 lbs. (327 kg) TNT - Later:  805 lbs. (365 kg) Torpex

11,000 yards (10,050 m)

41 knots

15,000 yards (13,700 m)

35 knots

                  
Ship Class Used On Leander (8 - bank of four 21" torpedo tubes on each beam) HMS Leander, Achilles, Neptune, Orion, Amphion, Apollo and Phaeton and later cruisers, "A" and later destroyer classes. Also replaced the old Mark VII in some 8" (20.3 cm) cruisers during the war

NOTES:

With the continued demand for more torpedoes, further schemes for increasing output were submitted to the Admiralty and eventually additional machine tools were purchased and installed. The total personnel gradually increased, until the Weymouth workforce reached 1,667 and production once again achieved twenty torpedoes per week. G. J. Kirby in his "History of the Torpedo" notes that the Whitehead Works produced the following torpedo types up to 1944:

MKVlll - 1394
MKlX - 109

horizontal rule

The Experimental Firing of a Torpedo
 Off Portland from HMS Thunderer in 1878

 By Ed Cumming

We present some illustrations of the recent practices off Portland on board HMS Thunderer, with this extraordinary weapon of Naval Warfare.  The general arrangement of the Whitehead "fish" torpedo may be described in a few words, it is a long cigar-shaped case of thin steel built in sections well screwed together.   Those recently on view at Woolwich Arsenal were about 17ft long from end to end, and each section was 15in wide in its widest part, and the steel about a sixteenth in thickness.  The first compartment, at the head, contains the charge of gun-cotton, to be fired by the forcing of a roughened pin into a cap of fulminate, on the torpedo coming into contact with anything after it has set in motion.  The second compartment contains Mr Whitehead’s great secret contrivance, which gives the operator control over the machine, so that he can make it run at any required depth under water.  The next section of the torpedo is the reservoir for compressed air, the motive power by which it runs along under water; then comes the machinery; and last of all the screw and rudders.  The screw is four-bladed, in appearance exactly like that of a steamer; but of the rudders there are two, one placed horizontally and the other vertically.  It is the horizontal rudder which submerges the torpedo and keeps it at the required depth until, its force being spent, it rises to the surface or sinks to the bottom, as may have been arranged in the manufacture.  Outside the case nothing is to be seen but a smooth, polished surface, with a small trigger on the upper part of the air chamber, and a few screws recessed for the reception of keys.  One of these, at the side of the second section, has an index attached, marked in feet, and this has merely to be turned to the required number for setting the torpedo to submerge itself and proceed along at the depth indicated.  The trigger above mentioned is merely a lever for opening the air- valve; and this is either done by hand when the torpedo is merely launched from a boat, or it is drawn back by a catch at a muzzle when it is shot out of a tube.   In order to prevent accidents there are two safety pins, which will not allow the fuse to act. The one is drawn at starting, but the other can be so arranged as to remain in its place until a certain number of revolutions of the screw have been made, by which the torpedo is carried to a safe distance.  The preparation and use of the Whitehead "fish" torpedo on board ship may now be described.

 

The sections of the torpedo are put together below, outside the torpedo-room, and it is run along the flats on a small truck until it is beneath a hatchway in nearly the centre of the battery deck, or citadel; through this it is hoisted by means of two Western tackles and one rope tackle, and placed in a light iron framework carriage, in which it is run from the hatchway to the torpedo-tube; here the carriage is placed so that the nose of the torpedo is pointed into the tub, and the tail is close  to  the  torpedo-charging  column.    The torpedo crew consists of six men, No 6 being stationed at the torpedo magazine below, the remaining five men with the torpedo.  Now, the torpedo being in its place, it is charged with compressed air by means of a small copper pipe, one end being screwed to he charging column, the other to a small hole in the left side of the torpedo, No 1 of the torpedo crew opening the valves in the charging-column to admit 750 lb of compressed air; this is the amount usually used for practice, 1000 lb to 1200 lb being the amount that the torpedo would be charged with for actual warfare.  On the gauge showing 750 lb No 1 shuts off his valves and unscrews the charging-pipe, and then proceed to set the wheel for the number of teeth ordered by the officer, the little wheel in the stern regulating the distance the "fish" is required to go, as it runs forty yards for every tooth.  This wheel also pulls out a safety wedge when the torpedo has gone eighty yards from the ship.  The depth having been set, and the amount of pressure in atmosphere for the required speed (which works up to twelve knots and a half an hour), the pistol, or firing apparatus, is screwed in, the safety-pin is withdrawn, and the torpedo is run into the tube.  The impulse tube is then put on, and the torpedo is reported, through a tube to the pilot tower, to be ready for firing.  The impulse tube is an affair very much resembling a telescope in form, which is forced out by compressed air, and pushing the tail of the fish, gives it a good start on its journey clear of the ship, the compressed air afterwards forcing the telescope in again.  As the torpedo is forced out, a small projection on the top of the inside of the tube catches a small lever on the top of the torpedo and throws it back.  This action opens the air-valve, and admits the air from the air chamber to the engines, and so sets the screws going.  For practice, a boat is sent out about 200 or 300 yards from the ship, either to pull past her or remain stationary, and a shot is taken at the boat, the torpedo being set to a sufficient depth to pass under her.  The effectiveness of the shot requires at present very good judgment on the part of the officer firing the torpedo; but then Commander Wilson’s torpedo-director is supplied to ships generally, the correctness of the shot will be almost a certainty. When the torpedo has finished its run, it rises to and floats on the surface of the water, and the boat then attaches a line to its nose and tows it back to the ship.  Brought alongside, a pair of tongs is lowered over the side and placed over the centre of the fish, and when fairly placed the catch that keeps the tongs open is pulled up, and the tongs close firmly round the body of the fish, the safety-pin having previously been put in over the air- lever, so that by any accident the engines should not be again started and the fish run away with its tongs.  When the tongs are firmly secured, the torpedo is pulled inboard, and is either taken to pieces or stowed away, or put together again and treated with another run.

 

The order for the new torpedo-vessels for the Royal Navy has been distributed among various shipbuilders, principally upon the Thames.  One, which is on the stocks at the works of Messrs Yarrow, at Poplar, has a length of 76ft by 10in beam, and a depth of 6ft 6in.  She is built entirely of steel on very fine lines, with a curved deck, and will be fitted with a pair of high- pressure compound engines of not less than 400-horse power indicated.  Being divided into a number of water-tight compartments, it will be difficult to sink one of these boats; and the electrician, steersman, engineer and stoker, who will be the only persons on board, will be all under cover, a small cowl on deck supplying fresh air both to them and the furnaces.  The Sartorius, armoured torpedo ram, to be built in Chatham Dockyard, will be constructed of steel, and will be propelled by twin screws.  Her length will be 250ft, her weight 2500 tons, and she will draw 20ft of water aft.  She is estimated to realize a speed of seventeen knots.  She will not be rigged, but will be built so as to carry a large supply of coals.  The outline sections of the vessel show that she will to a great extent resemble the American cigar-ship, the principal difference being that the lower part is fashioned to form a keel for grounding upon, and that the upper part, which is in the form of a cylindrical crown, runs nearly parallel to the water.  The crown is 4ft 6in above the water; but above this will be a flying deck of a similar character to those of the Devastation and the Thunderer, but of much lighter construction.  This flying or hurricane deck will be 6ft above the water.  The crown will not be fitted as a deck except at the ends of the vessel.  There will be a platform forward to bring the anchors in upon, while aft there will be a deck to provide accommodation for the officers.  The fore end of the ship is shaped into a powerful ram.  The ship will carry no guns, but from each side of her ram she will be able to discharge the new "Laboratory" torpedo from her bow compartment.  She will also be able to discharge these terrible weapons from a chamber amidships, between the boiler and engine compartments.

horizontal rule