21-in Mark II Torpedo (UK)

R.G.F. Torpedoes Mark I and II, 1909

The 21-in R.G.F. Mark II Torpedo was a British torpedo developed at the Royal Gun Factory and first ordered for service in 1909-1910.^{[Citation needed]}

Development and History

It was developed in parallel with the Mark I torpedo, which was shorter at 18.5 feet.

Mark II

In 1909-1910, 4 hook bracket torpedoes were ordered.^{[Citation needed]}

Mark II*

Introduced in 1914, these featured rectified threads throughout, air vessel pressures of 2,350 psi for 10,750 yard range and two other improvements.

Mark II**

Introduced in 1914, these included the improvements of the II** and added three other small features.

Mark II***

In 1915, Commander-in-Chief Home Fleet wanted a proportion of torpedoes able to reach the greatest possible range. By year's end, trials of a torpedo with a projected range of 18,000 yards at 19-20 knots were anticipated.