This article is a start at cataloguing the German torpedoes as I have done for the British.
The British learned about German torpedoes by the occasional discovery and capture of one that was lost in battle or found on an enemy ship.
The British recorded particulars of "two early types" — a 45cm (~17.8-in) bronze one and a 45cm steel one from Emden which they surmised was the first German heater. The Germans also purchased and used 21-in Schwartzkopf torpedoes.
The British studied
- three more 45cm bronze torpedoes
- a 45cm steel Fiume torpedo (No. 11582, originally ordered for Brazil)
- a 50cm (~19.7-in) steel dry heater torpedoes No 5955 from captured U.B. 26
- another, No. 7460 from the sea off Haddingtonshire
- a 45cm Fiume ex-Italian torpedo was recovered off Fiume by the French
- a 45cm example courtesy of the Russians, similar to the 50cm model
- a fragment of a torpedo indicating it was from a wet heater
By mid-1017, these discoveries brought the present understanding of German types to the following.
|diam||Type||Date||Heater||Range (m)||Est. Knots||Warhead||Notes|
|1895-1898||None||2,400||18||250 lb wet G.C.||Similar to 18-in Mark IV w/ heavier head|
|Emden||1907||Dry||4,000||24-25||300 lb wet G.C.||like 18-in F III** H, set to lower speed/greater range|
|—||Dry||—||—||—||like 18-in Weymouth I*|
|Fiume||1913||Dry||4,000||29||361 lb Hexonite||No. 11582, ordered for Brazil, picked up by trawler Cornet and given to Laburnum|
|?Italy||Wet||6,000||—||—||manufactured for Italy|
|Swartzkopf||Recent||Steam||4,000||30||255 lbs TNT|
|357 lbs Hexonite||like 21-in Mark I w/ heavier head, lower speed, same range|
No. 5955 from UB 26
|397 lbs TNT||like 21-in Weymouth II|
It was otherwise assumed that the latest German torpedoes would be at least as good as a British Mark II***. That the German range at Eckernforde was known to be 14,000 yards was taken as implication that the normal range for a German torpedo might be 12,000 metres. Some torpedoes sighted at Jutland had been estimated to be making 20 knots, a speed at which it was estimated the 197.-in designs might reach 12,000m.
Torpedo No 11582 seemed to have been damaged badly by the explosion of another torpedo, and had been at the bottom of the sea for perhaps over a year. It was 45cm with no net cutter, a four bladed prop and Fiume tail and counter marked to 4,000 metres and air=spun, angled gyro, with estimated data of 17 feet overall, 2100 psi for 11.5 cubic feet, 1,500 pounds uncharged, 488.5 lbs head with 351 lbs explosive. The Fiume inertia pistol was designed to be safe for just 25 yards
Torpedo No 5955 was removed complete with net cutter from salved U.B. 26 by the French.
Torpedo No 7460 had seemingly been lost on a practice run and offered the following data. Length oa 19ft 4 in, 160 kgs/sq cm (2375 psi) for 19 cubic feet. 1570 lbs uncharged, head 433 lbs 3 oz with 357 lbs 1 oz hexonite. Top suspension, 6,000m marked on counter, at estimated 30 knots. 3 bladed prop with Woolwich tail and air-driven, angled gyro. The net cutter was explosive.
The understanding of German broadside tubes was based solely on the fittings of the 18-in Emden torpedo. It was estimated that the German torpedo would slew 3.75 degrees vertically and 2.75 degrees in the tube, as opposed to 9 and 9.5 degrees for the British 18-in G.S. 1 torpedo. Inferences were made as to the tube design (possibly side-loading) and that the torpedo would deflect 20 degrees with an ejection velocity of 50 fps.
The U.B. 26 tube and torpedo were fitted with gyro angling gear able to go 90 degrees either side in coarse 15 degree increments "which would not be at all easy to manage." The firing buttons were on the deck below the conning tower, and a voicepipe from the upper conning tower ran direct to the tubes. Interlocking gear was "elaborate and complete." Gyro angles could be applied to torpedoes in the tube by pulling a knob out and then turning it to either side through keyed detent positions.
The British could offer more insights into the German weaponry by the end of 1918.
They had picked up one K III (No. 10242), two G 6 A.V.** and three G 7** types during 1918 – none had been recovered before – as well as G 6 A.V.* or K IV torpedoes from the salved UB 110. it was surmised that the Germans had nearly run out of their stocks of older types. By early 1918, the K III, G 6 A.V. and G 7** torpedoes were assumed to be the majority of those in service.
No K, K I or K II torpedoes had ever been seen, but were presumed to be dry heaters similar to the G 6 A.V. but more coarsely made and having poor depth-keeping.
K III torpedoes were introduced in March 1917 and did not require much maintenance but they had short range which made them less useful if escorts could prevent a close approach. A K IV type may also have existed, but not all torpedoes had types stamped on them. The numbers stamped on those recovered were all over 11,000, which prompted the assumption that production was very high.
Six Fiume torpedoes of G/125 type were found on one of the Orkney islands, seemingly jettisoned from a U-boat which had tried to lighten ship after running aground. G 6 A.V.** No 9346 was found with its head off, apparently knocked off by the propellers of the target this torpedo had been observed passing under. The engine of another such weapon, No 9496 was found with some damage.
The G 6 A.V.** was 50-cm, 20 feet overall. it had no hook brackets or sinking valve. The air vessel working pressure was 2,375 psi in 18.75 cubic feet. Total weight was 2,425 pounds.
The G 7** was 22 feet, 11.625 inches overall (head 36.125 inches, air vessel 10 feet 11.75 inches, water bottle 1 foot 5.75 inches, afterbody 6 feet 11.5 inches). It weighed 2,915 pounds, approximately, and varied from 360 pounds negative buoyancy to 55 pounds positive. It had three bladed propellers. Charging pressure was 2,275 psi in 22 cubic feet. Fuel was 312 fluid ounces. The engine was bronze and had four cylinders. The double gyro could be angled in 15 degree steps "by the method used in all German torpedoes." All G 7 types used the same "Type II" double gyro.
|50-cm||G 6 A.V.||6,020 yards at 27 knots
2,400 yards at 38 knots
|G 6 A.V.*||5,468 yards at 26 knots
2,187 yards at 38 knots
|G 6 A.V.**||5,468 yards at 27 knots|
2,187 yards at 40 knots
|G 7||8.968 yards at 28.5 knots
4,046 yards at 35 knots
|G 7*||10,061 yards at 28.5 knots|
4,921 yards at 35 knots
|G 7**||11,264 yards at 28.5 knots
5,468 yards at 35 knots
|G 7***||11,701 yards at 28.5 knots
5,468 yards at 35 knots
|K III||1,300 yards at 31 knots
1,600 yards at reduced speed
In May, 1917, part of a magnetic firing pistol was found inside a torpedoed oiler, but its significance was not recognized. Interviews of captured Germans later in 1917 brought news that they were using such fuzes, and it was thought that perhaps this accounted for German torpedoes that seemed to detonate without hitting anything. Late in 1918, when UB 110 was salvaged, these devices were found. They were fitted onto the nose of a regular torpedo head and had a small, separate priming charge they would trigger which would, in turn, strike the contact fuze of the torpedo head.
A K III torpedo, No. 10,242 was fired at a French steamer Champlain. The torpedo broke surface and Champlain fired on it, miraculously hitting it and destroying its head. It was later salved by the trawler Lark and examined. Its cheapness in manufacture was notable. Somehow the British determined that all K III torpedoes are numbered over 10,000. They are 50-cm, 13.25 feet in length (without head) and the one recovered had no heater. Two bladed props, three cylinder engine and top suspension for discharge. No sinking gear was fitted, leading to the assumption that the warhead was a heavy one. It weighed 1,275 pounds empty without its head. The air vessel was about 12.5 cubic feet and could be charged to 2,125 psi.
In 1919, the British reported on the Fore Bridge Firing Gear and Director and a "decidedly crude" tube-mounted director from German destroyers.
The former was on a conical pedestal and contained the director and telescopic sight as well as magneto firing gear for the tubes. The one examined supported one S.R. tube and two D.R. tubes fanned 12 degrees apart in the customary German manner. The instrument was fashioned entirely of brass and was on the "three-bar principle". A beveled base plate with a semi-circular arc was marked 0 to 180 degrees for training of the tube. This meant that a separate device was needed for port and for starboard. The base plate had notches at 20, 55, 75, 80, 95, 110 and 125 degrees, corresponding to the locking positions of the various tubes, the numbers of which were also stamped on the base plate.
A spring trigger allowed the torpedo bar (the end of which formed a hand-grip) to be locked into the baseplate at any of these notches. A milled screw allowed torpedo speeds from 28 to 45 knots to be selected. The enemy bar could be set from 0 to 40 knots, the slider being locked down by a milled screw. There was no rack and pinion for this slider as on some British sights; one had to push the slider along by hand. Enemy heading was set by "track angle" as read off a scale mounted under the pivot; there was no means of expressing the enemy heading in terms of Inclination as on many contemporary British sights. The sight bar carried "possible shot" strips on each side, the ones inspected being a pair for two settings on the G 7*** torpedo, one for 35 knots to 500m and the other 28.5 knots to 10,700m. The sights were simply vertical wires in frames. A bracket on top of the director permitted the telescopic sight to be fitted.
The telescopic sight was a monocular affair made by Voigtlander with a dummy second eye piece on a swivelling bracket, to permit the operator to choose either eye for the effective eye piece. The eyepieces had rubber guards and the effective one also had a protective cap. A pair of objective glasses offered a plain view in the lower position and a 6-diameters magnified view through the upper one. A milled head on the right hand side allowed the operator to choose between these objectives, and focussing arrangements were provided. Open sights were provided on top of the telescope assembly. The firing magneto was clockwork powered. When fully wound, an indicator read "Schuss". When the firing handle was worked, the clockwork would spin the magneto and generate the firing current.
The german tube-mounted director examined was very simple. The torpedo bar could record speeds from 22 to 45 knots and the enemy bar could record 0 to 40 knots. Enemy heading was again recorded only by track angle without support for inclination. The backsight could swivel and the foresight was a simple pin sight. There was no means of correcting the alignment of the sight.
- Annual Report of the Torpedo School, 1916, p. 110. alluding to reference in ARTS, 1915
- Annual Report of the Torpedo School, 1916, p. 110.
- Annual Report of the Torpedo School, 1916, p. 110.
- Annual Report of the Torpedo School, 1916, p. 111.
- Annual Report of the Torpedo School, 1916. p. 111. Plates 36-7, pistol in Plates 38-39.
- Annual Report of the Torpedo School, 1916. p. 113. Servo motor depicted Plate 41. Photo of parted torpedo in Plate 42.
- Annual Report of the Torpedo School, 1916, p. 114. Net cutter in Plate 40.
- Annual Report of the Torpedo School, 1916. p. 114-115.
- Annual Report of the Torpedo School, 1916. p. 116. Gyro angle setting assembly diagrammed on p. 116, air discharge arrangements in Plate 43, depth-keeping mechanism in Plate 44.
- Annual Report of the Torpedo School, 1918. Plate 106.
- Annual Report of the Torpedo School, 1918. pp. 137-150.
- Annual Report of the Torpedo School, 1918. Plate 88.
- Annual Report of the Torpedo School, 1919. Plate 92.
- Annual Report of the Torpedo School, 1919. pp. 207, 208.
- Annual Report of the Torpedo School, 1919. Plate 93.
- Annual Report of the Torpedo School, 1919. Plate 94.
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