14-in Mark IX Torpedo (UK)
The 14-in Mark IX Torpedo was a British torpedo manufactured by the Royal Gun Factory at Woolwich.
It was to enjoy an uncommonly long stint as the Royal Navy's 14-in torpedo, from 1896 to 1898.
Development and History
The design was submitted and agreed to after changes were applied in December 1891. An overarching goal of the design was to incorporate lessons taken from manufacture of the new 18-in models. The body shape was the same as in the Mark VIII model, but the tail fins were to be like those of the new 18-in long R.G.F. model which could better pass through nets. Overall, its design was described as being different in 10 points from the Mark VIII's, and a pound lighter when charged (705 versus 706 pounds).
The Admiralty stressed there was no hurry to have this new torpedo, as the coming year's small order could just be more of the Mark VIII design. They also asked that the idea of enlarging the warhead by fitting a bluffer head be considered, as these were proving the better shape anyway. It was understood that this might increase weight to about 750 pounds.
They provided sketches of a model with these features with a warhead of 112 pounds. Order and manufacture of two articles was made in 1892.
Tests conducted at the end of 1893 were deemed unsatisfactory, requiring further testing and a further report after altering the side lugs. Phosphor bronze afterbodies proved too delicate and collapsed after above-water firings. Steel afterbodies and three-bladed propellors were mandated for further testing, resulting in a satisfactory report in May, 1894 in which the torpedo was judged to improve upon the Mark VIII in many ways:
- faster by 2 knots
- warhead 11 pounds more dry guncotton (actually, 90 vs 76 pounds with wet guncotton)
- steadier in direction
- greatly superior depth keeping, particularly when used from drop collars
- a tail and propellors better shaped to avoid being caught up in nets
The report also expressed the conclusion that the new three-bladed propellors passed through nets cleanly enough that Fiume tails should not be employed.
Indeed, in 1894, after some refinements were applied by Whitehead to the two 14-in Fiume Mark V torpedoes being evaluated, follow-up testing of the two specimens at Portland proved so unsuccessful that Mr. Whitehead deemed them defective and personally withdrew them from trial. The Admiralty subsequently decided to have Portland switch over and manufacture the superior Mark IX weapon, which was to become universal for the Royal Navy for torpedoes of this size, until they were supplanted by the 14-in Mark X torpedo in 1898.
At the end of 1895, the Mark IXs were just ready to come into service.
In 1894, it was reported that the fully charged torpedo weighed 722 pounds.
The final design is extensively laid out in the Annual Report of the Torpedo School, 1895.
The diameter was precisely 14 inches, but the specification allowed 14.015 inches, uncharged, as a maximum. It carried a charge of 79 pounds dry guncotton, 90 when wetted.
With pistol but without air: weight 696 pounds, metacentric height 0.5 inches and C.G. 99.52 inches from end of screw shaft. When charged with 28.5 pounds of air, C.G. is 100.43 inches from end of screw shaft. The pistol projected 4.35 inches with a left-handed fan which was 5 inches tip-to-tip. The warhead was cissoid shaped, 26.1 inches long, of sheet phosphor bronze, and weighed 122 pounds with its 90 pound wet guncotton charge. An exercise head of the same shape, weight and metacentric height of 0.7 inches. It could receive the same Holmes light as the R.G.F. Mark VIII weapons.
Uncharged with pistol, it had a buoyancy of 11 pounds in fresh water. When charged with 28.5 pounds of air with pistol, it was ballasted and adjusted to float horizontally and upright in salt water at a density of 1.026, at 60° F.
The engines 40.884 H.P., delivering 1006 R.P.M. over a 600 yard run. The top fin was 0.148 inches thick, the bottom 0.18 and the sides 0.155. The two steel three-bladed propellors had increasing pitch, mean pitch of 36 inches.
The proof and passing tests were six runs when charged to 1,350 psi:
- two runs from a submerged frame at target 600 yards distant
- two runs from an A.W. tube at least four feet above the water at a target 300 yards away
- one run above water at target 600 yards away
- one run from submerged frame at target 600 yards away
The limits of deviation permitted were:
- lateral deviation from the submerged frame must be less than 9 yards either way throughout run
- from A.W. tube, lateral deviation of 6 yards at 300 yards or 18 yards at 600 yards
- deviation from set depth not to exceed +/- 18 inches
The speeds required were:
- not less than 27 knots in 60° and warmer
- not less than 26.5 knots in 50-60°
- at least 26 knots in water colder than 50°
Endurance was tested in just one torpedo in a batch of twenty, after passing the above tests:
- make six short runs from above water gun 10 feet or more above water
- be fired from submerged frame and pass within 10 yards of target at 600 yards
- it must then "shew no signs of weakness or distortion"
Lastly, one torpedo of every ten was to be tested for interchangeability.
Manufacture and Use
Horsea adjusted the first 69 torpedoes in 1896. They averaged 27.21 knots at 600 yards in 44.7 degree water.
Whitehead-made specimens were passed at Weymouth in three groups, delivering the following average speeds to 600 yards:
- thirty-six torpedoes averaged 27.55 knots in 52.3 degree water.
- thirteen torpedoes averaged 27.90 knots in 57.7 degree water.
- twelve torpedoes averaged 27.31 knots in 48.6 degree water.
Eighty are ordered and are under manufacture at Woolwich.
By 1915, at least, these were noted as having 1,600 psi air vessels and a setting of 23 knots to 1,00 yards.
In 1916, it was decided that the warhead of 14-inch torpedoes should be filled with Amatol. The Mark IXs were to have 110 pounds of this explosive.
180 of 326 remaining torpedoes were broken up in 1918.
- Annual Report of the Torpedo School, 1893. portion of Plate 10.
- Annual Report of the Torpedo School, 1892. pp. 20-21.
- Annual Report of the Torpedo School, 1892. p. 22.
- Annual Report of the Torpedo School, 1892. pp. 20-24.
- Annual Report of the Torpedo School, 1894. pp. 51-3.
- Annual Report of the Torpedo School, 1894. pp. 58, 62-3. (Admiralty Letter, G. 5476/7433, 19 Oct 1894).
- Annual Report of the Torpedo School, 1898. pp. vi-vii.
- Annual Report of the Torpedo School, 1894. p. 53.
- Annual Report of the Torpedo School, 1895. pp. 30-37, Plates 2-6.
- Annual Report of the Torpedo School, 1896. pp. 42.
- Annual Report of the Torpedo School, 1896. p. 43.
- Annual Report of the Torpedo School, 1897. p. 18.
- Annual Report of the Torpedo School, 1915. p. 31.
- Annual Report of the Torpedo School, 1916. p. 47.
- Annual Report of the Torpedo School, 1918. p. 10. (G. 8472/18).
- Annual Report of the Torpedo School, 1919. p. 11.
- 18-in Mark IV torpedo, its contemporary