18-in Mark VII Torpedo (UK): Difference between revisions

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[[File:ARTS1908Plate12.jpg|thumb|600px|'''18-in R.G.F. Mark VII Torpedo'''{{ARTS1908|Plate 12}}]]
[[File:ARTS1890Plate1.jpg|thumb|600px|'''Short 18-in Torpedoes, 1890'''{{ARTS1890|Plate 1}}]]
[[File:ARTS1909Plate2.jpg|thumb|600px|'''18-in R.G.F. Mark VII* Torpedo (bottom)'''{{ARTS1909|Plate 2}}]]
[[File:ARTS1891Plate5.jpg|thumb|600px|'''18-in R.G.F. Torpedo Tail, 1891'''{{ARTS1891|Plate 5}}]]
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The '''18-in R.G.F. Mark VII Torpedo''' was a British torpedo developed at the [[Royal Gun Factory]] and first ordered for service in 1908 in its VII* variant.{{FC}}
The '''18-in R.G.F. Mark VII Torpedo''' was a British torpedo developed at the [[Royal Gun Factory]] and first ordered for service in 1908 in its VII* variant.{{FC}}
Unlike the {{Torp|Mark VI|UK}}es, there were heater torpedoes by nature, and so are never qualified by a "H.".


==Development and History==
==Development and History==
Ovalling gear was being trialled at sea in 1917.{{ARTS1917|p. 25}}
==Particulars==
It was hoped that these might deliver more than 41 knots, but depth-keeping issues observed above 43 knots caused them to be rated at lower speed.{{ARTS1909|p. 12}}
Its overall length including 4.5-in long pistol was 17 feet, 7.4 inches (see Plate).{{ARTS1908|p. 18}}
In its Mark VIII S.L. version, it achieved 29-31 knots to 5,500 yards and 40.5-41.5 to 3,00 yards.
==Manufacture and Use==
===Mark VII===
The raw Mark VII torpedo was first ordered in 1910-1911; oddly, this is after the Mark VII* and Mark VII** variants in 1908-1909.  More careful reading is required.
In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:{{ARTS1917|pp 25-26}}
* 35 knots to 4,500 yards
* 29 knots to 6,000 yards
===Mark VII*===
Forty S.L. torpedoes were ordered in 1908-1909, but were somehow only reported the following year.{{ARTS1909|p. 7}}
These contained more fuel and water but less air than the raw Mark VII, yielding an increase in range, at least under the low speed setting: 29-31 knots to 6,500 yards and 40.5-41.5 over 3,000 yards.{{ARTS1909|pp. 11-2}}
In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:{{ARTS1917|pp 25-26}}
* 35 knots to 4,500 yards
* 29 knots to 6,500 yards


===Particulars===
===Mark VII**===
<!--
Some 53 Hook Bracket and 143 Side Lug specimens were ordered or given heaters in 1908-1909 &ndash; the source needs to be read more carefully.{{CN}}
The final design's characteristics are detailed in the ''Annual Report of the Torpedo School, 1901''.{{ARTS1901|pp. 36-7}}
The construction was very similar in materials to the 14-in Mark IX torpedo.


* Diameter: 17.71 inches
In 1914, however, these are referred to as "new" torpedoes, with rectified threads throughout, B<sub><small>2</small></sub> generators and air vessel pressures increased to 2,200 psi to deliver 29 knots to 7,00 yards.{{ARTS1914|p. 8}}
* Length: 16 feet, 7.4 inches
* Weight with pistol, without air: 1,156 pounds
* Metacentric height: at least .575 inches
* C.G. distance from tip of shaft, no air: 114.175 inches
* C.G. distance from tip of shaft, 60 pounds air: 114.35 inches
* Warhead:  200 pounds wet guncotton
It carried a charge of 170 pounds, 15 ounces &ndash; the same as in the [[18-in R.G.F. Mark III Torpedo|Mark III torpedo]].


It had a Brotherhood engine of 3.25x3 inches.
In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:{{ARTS1917|pp 25-26}}
* 35 knots to 5,000 yards
* 29 knots to 7,000 yards


Mean pitch of propellors was 40 inches.  When charged with air, the torpedo must pass through a gauge 9 inches long and 17.725 inches internal diameter.
Conversion of Marks VII** to VII***** to E.R. 3 was undertaken in 1917, but by year's end, only 21 had been converted.   


With pistol and charged with 60 pounds of air was ballasted and adjusted to float horizontally and upright in salt water at a density of 1.026 and 60 degree temperature. In fresh water, with pistol and no air, it had a buoyancy of 31 pounds.  
==Mark VII***==
Introduced in 1914, these combined some additional small improvements to those of the VII**.{{ARTS1914|p. 8}}


The proof and passing tests were six runs when charged to 1,350 psi:
In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:{{ARTS1917|pp 25-26}}
* two runs from a submerged frame at target 800 yards distant
* 35 knots to 5,000 yards  
* two runs from an A.W. tube at least four feet above the water at a target 400 yards away
* 29 knots to 7,000 yards  
* one run above water at target 800 yards away
* one run from submerged frame at target 800 yards away


The limits of deviation permitted were:
==Mark VII****==
* lateral deviation from the submerged frame must be less than 12 yards either way throughout run
Introduced in 1916, these had interchangeable warheads with earlier Mark VII torpedoes and combined some 18 additional small improvements to those of the VII***, including:{{ARTS1916|p. 39}}
* from A.W. tube, lateral deviation of 8 yards at 400 yards or 24 yards at 600 yards
* Tail of H.B. 1/S.L. 1 type
* deviation from set depth not to exceed +/- 18 inches
* Wider gyroscope rudders
* strengthening rings in afterbody


The speeds required were:
In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:{{ARTS1917|pp 25-26}}
* not less than 30 knots to 600 yards and 29 knots to 800 yards in 60 degrees and warmer
* 35 knots to 5,000 yards  
* not less than 29.5 knots to 600 yards and 28.5 to 800 yards in 50-60 degrees
* 29 knots to 7,000 yards  
* at least 29 knots to 600 yards and 28 knots to 800 yards in water colder than 50 degrees


Endurance was tested in just one torpedo in a batch of twenty, after passing the above tests:
==Mark VII*****==
# make six short runs from above water gun 10 feet or more above water
[[File:ARTS1918Plate76.jpg|thumb|300px|'''Depth-taking Test from submarine launch'''{{ARTS1918|Plate 76}}]]
# be fired from submerged frame and pass within 14 yards of target at 800 yards
Introduced in 1917, these were almost identical to the VI****, but had small improvements in constructions and could withstand 100 psi pressures.{{ARTS1917|p. 27}}
# it must then "shew no signs of weakness or distortion"
 
-->
In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:{{ARTS1917|pp 25-26}}
==Manufacture and Use==
* 35 knots to 5,000 yards
I've not found an indication that the raw Mark VII torpedo was ever ordered; only the Mark VII*, first in 1908-1909.
* 29 knots to 7,000 yards


==Mark VII*==
Forty were ordered in 1908-1909.{{CN}}
==Footnotes==
==Footnotes==
{{reflist}}
{{reflist}}

Latest revision as of 17:19, 3 July 2018

18-in R.G.F. Mark VII Torpedo[1]
18-in R.G.F. Mark VII* Torpedo (bottom)[2]

The 18-in R.G.F. Mark VII Torpedo was a British torpedo developed at the Royal Gun Factory and first ordered for service in 1908 in its VII* variant.[Fact Check]

Unlike the Mark VI torpedoes, there were heater torpedoes by nature, and so are never qualified by a "H.".

Development and History

Ovalling gear was being trialled at sea in 1917.[3]

Particulars

It was hoped that these might deliver more than 41 knots, but depth-keeping issues observed above 43 knots caused them to be rated at lower speed.[4] Its overall length including 4.5-in long pistol was 17 feet, 7.4 inches (see Plate).[5]

In its Mark VIII S.L. version, it achieved 29-31 knots to 5,500 yards and 40.5-41.5 to 3,00 yards.

Manufacture and Use

Mark VII

The raw Mark VII torpedo was first ordered in 1910-1911; oddly, this is after the Mark VII* and Mark VII** variants in 1908-1909. More careful reading is required.

In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:[6]

  • 35 knots to 4,500 yards
  • 29 knots to 6,000 yards

Mark VII*

Forty S.L. torpedoes were ordered in 1908-1909, but were somehow only reported the following year.[7]

These contained more fuel and water but less air than the raw Mark VII, yielding an increase in range, at least under the low speed setting: 29-31 knots to 6,500 yards and 40.5-41.5 over 3,000 yards.[8]

In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:[9]

  • 35 knots to 4,500 yards
  • 29 knots to 6,500 yards

Mark VII**

Some 53 Hook Bracket and 143 Side Lug specimens were ordered or given heaters in 1908-1909 – the source needs to be read more carefully.[Citation needed]

In 1914, however, these are referred to as "new" torpedoes, with rectified threads throughout, B2 generators and air vessel pressures increased to 2,200 psi to deliver 29 knots to 7,00 yards.[10]

In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:[11]

  • 35 knots to 5,000 yards
  • 29 knots to 7,000 yards

Conversion of Marks VII** to VII***** to E.R. 3 was undertaken in 1917, but by year's end, only 21 had been converted.

Mark VII***

Introduced in 1914, these combined some additional small improvements to those of the VII**.[12]

In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:[13]

  • 35 knots to 5,000 yards
  • 29 knots to 7,000 yards

Mark VII****

Introduced in 1916, these had interchangeable warheads with earlier Mark VII torpedoes and combined some 18 additional small improvements to those of the VII***, including:[14]

  • Tail of H.B. 1/S.L. 1 type
  • Wider gyroscope rudders
  • strengthening rings in afterbody

In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:[15]

  • 35 knots to 5,000 yards
  • 29 knots to 7,000 yards

Mark VII*****

Depth-taking Test from submarine launch[16]

Introduced in 1917, these were almost identical to the VI****, but had small improvements in constructions and could withstand 100 psi pressures.[17]

In submarine use (at least), in 1917 it was decided that they were to be altered to deliver:[18]

  • 35 knots to 5,000 yards
  • 29 knots to 7,000 yards

Footnotes

  1. ↑ Annual Report of the Torpedo School, 1908. Plate 12.
  2. ↑ Annual Report of the Torpedo School, 1909. Plate 2.
  3. ↑ Annual Report of the Torpedo School, 1917. p. 25.
  4. ↑ Annual Report of the Torpedo School, 1909. p. 12.
  5. ↑ Annual Report of the Torpedo School, 1908. p. 18.
  6. ↑ Annual Report of the Torpedo School, 1917. pp 25-26.
  7. ↑ Annual Report of the Torpedo School, 1909. p. 7.
  8. ↑ Annual Report of the Torpedo School, 1909. pp. 11-2.
  9. ↑ Annual Report of the Torpedo School, 1917. pp 25-26.
  10. ↑ Annual Report of the Torpedo School, 1914. p. 8.
  11. ↑ Annual Report of the Torpedo School, 1917. pp 25-26.
  12. ↑ Annual Report of the Torpedo School, 1914. p. 8.
  13. ↑ Annual Report of the Torpedo School, 1917. pp 25-26.
  14. ↑ Annual Report of the Torpedo School, 1916. p. 39.
  15. ↑ Annual Report of the Torpedo School, 1917. pp 25-26.
  16. ↑ Annual Report of the Torpedo School, 1918. Plate 76.
  17. ↑ Annual Report of the Torpedo School, 1917. p. 27.
  18. ↑ Annual Report of the Torpedo School, 1917. pp 25-26.

Bibliography

See Also

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