18-in Mark VII Torpedo (UK)
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
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.
Mark VII*
Forty S.L. torpedoes were ordered in 1908-1909, but were somehow only reported the following year.[6]
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.[7]
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.[8]
Mark VII***
Introduced in 1914, these combined some additional small improvements to those of the VII**.[9]
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:[10]
- Tail of H.B. 1/S.L. 1 type
- Wider gyroscope rudders
- strengthening rings in afterbody
Mark VII*****
Introduced in 1917, these were almost identical to the VI****, but had small improvements in constructions and could withstand 100 psi pressures.[11]
Footnotes
- ↑ Annual Report of the Torpedo School, 1908. Plate 12.
- ↑ Annual Report of the Torpedo School, 1909. Plate 2.
- ↑ Annual Report of the Torpedo School, 1917. p. 25.
- ↑ Annual Report of the Torpedo School, 1909. p. 12.
- ↑ Annual Report of the Torpedo School, 1908. p. 18.
- ↑ Annual Report of the Torpedo School, 1909. p. 7.
- ↑ Annual Report of the Torpedo School, 1909. pp. 11-2.
- ↑ Annual Report of the Torpedo School, 1914. p. 8.
- ↑ Annual Report of the Torpedo School, 1914. p. 8.
- ↑ Annual Report of the Torpedo School, 1916. p. 39.
- ↑ Annual Report of the Torpedo School, 1917. p. 27.
Bibliography
