HMS Velox (1902)

HMS Velox was a turbine-powered torpedo boat destroyer (or "TBD") of the British Royal Navy in 1899 by Hawthorn Leslie and Company at Hebburn on the River Tyne. Velox was built speculatively by Hawthorn Leslie and Company with machinery by Parsons Marine, being launched in 1902, and was purchased by the Royal Navy, entering service in 1904. Velox served in the First World War, being sunk by striking a mine in 1915.

Design and construction
The British Admiralty, eager to investigate the use of steam turbines in warships, ordered the experimental destroyer HMS Viper (1899) from Parsons Marine in 1898, and purchased HMS Cobra (1899), also turbine-powered, built as a private venture by Armstrong Whitworth, in 1900. Both ships were quickly lost however, with Viper running aground off Alderney on 3 August 1901, and Cobra broke in half while on her delivery voyage on 19 September 1901. The Admiralty was still keen to adopt turbines, and so decided to buy a turbine-powered destroyer that was being built as a private venture by Parsons, the Python.

Python had been laid down at Hawthorn Leslie and Company's Hebburn, Tyneside shipyard (as for Viper, Parsons had sub-contracted build of the hull to Hawthorn Leslie, with the ship's machinery to be provided by Parsons) on 10 April 1901 and launched on 11 February 1902.

The ship was powered by two sets of compound steam turbines, each consisting of a high-pressure and low-pressure turbine driving a separate propeller shaft, with the high-pressure turbines driving the outer shafts and the low-pressure turbines the inner shafts giving four shafts in all. Two propellers were fitted to each shaft. A new feature was that a pair of small triple expansion engines (rated at 150 ihp each) that could be coupled to the inner, low-pressure turbine shafts for efficient cruising. Parsons were prepared to guarantee that the ship could reach a speed of 32 kn forward and 12 kn astern during sea trials, but hoped for speeds of 33+3/4 kn and 16 kn respectively.

The ship was 215 ft long overall and 210 ft between perpendiculars, with a beam of 21 ft and a draught of 5 ft. Displacement was 400 LT normal and 462 LT deep load. As well as the normal rudder at the ship's stern, a retractable rudder was fitted forward to aid manoeuvrability when running astern. Three funnels were fitted, while the ship's crew consisted of 63 officers and men. Armament was the standard for the thirty-knotters, i.e. a QF 12 pounder 12 cwt (3 in calibre) gun on a platform on the ship's conning tower (in practice the platform was also used as the ship's bridge), with a secondary armament of five 6-pounder guns, and two 18-inch (450 mm) torpedo tubes.

The Admiralty signed a contract for Python in May 1902, renaming the ship HMS Velox. As experience with earlier destroyers had shown that the speeds achieved in sea trials, which were ran lightly loaded, were not representative of speeds in service, it was specified by the Admiralty that trials should instead be carried out fully loaded. Velox was the first destroyer to be affected by this policy, which caused Parsons to cut the guaranteed speed to 27 kn.

Sea trials showed that Velox was as fast as hoped, reaching a speed of 34.5 kn at light load, and when fully loaded as according to contract requirements, making 27.249 kn over the measured mile and an average speed of 27.142 kn. Fuel consumption was significantly higher than expected, however, being up to 80% higher than the normal thirty knotters. Velox was commissioned in February 1902.

Service
Velox was not a success in service, partly due to the very high fuel consumption. This was not helped by the fact that the cruising engines could only drive the ship at 10.35 kn which was less than the cruising speed of the fleet. Other problems included slow astern speeds (about 5 kn only) together with an inability to quickly change the engines to run astern and problems associated with the location of the condensers. The cruising engines were replaced by cruising turbines in 1907.

In May 1909, Velox was passing Lands End when her port engines failed and heavy rolling caused a loss of feedwater supply to her condensers. This almost caused a complete loss of power off a dangerous lee shore. After this incident, Velox was transferred from normal flotilla duty to be attached to HMS Vernon, the Royal Navy's torpedo establishment as a training vessel. As such, Velox would not need to operate in poor weather which could cause a similar failure.

On 30 August 1912 the Admiralty directed all destroyers were to be grouped into classes designated by letters based on contract speed and appearance. As a three-funneled destroyer, Velox was assigned to the C Class.

Velox remained attached to HMS Vernon on the outbreak of the First World War in August 1914. In January 1915, Velox was assigned to the local patrol flotilla at Portsmouth.

On 25 October 1915, Velox was on patrol with the destroyer HMS Conflict (1894) when condenser problems forced Velox to seek calmer waters near the Isle of Wight. Velox struck a mine laid by the German submarine SM UC-5 off the Nab Lightship, killing four crewmen and badly damaging the ship's stern. Attempts to tow Velox to safety were unsuccessful, and Velox sunk.