HMS Derby (J90)

HMS Derby was a Hunt-class minesweeper of the Aberdare sub-class built for the Royal Navy during World War I. She was not finished in time to participate in the First World War and survived the Second World War to be sold for scrap in 1946.

Design and description
The Aberdare sub-class were enlarged versions of the original Hunt-class ships with a more powerful armament. The ships displaced 800 LT at normal load. They had a length between perpendiculars of 220 ft and measured 231 ft long overall. The Aberdares had a beam of 26 ft and a draught of 7 ft. The ships' complement consisted of 74 officers and ratings.

The ships had two vertical triple-expansion steam engines, each driving one shaft, using steam provided by two Yarrow boilers. The engines produced a total of 2200 ihp and gave a maximum speed of 16 kn. They carried a maximum of 185 LT of coal which gave them a range of 1500 nmi at 15 kn.

The Aberdare sub-class was armed with a quick-firing (QF) 4 in gun forward of the bridge and a QF twelve-pounder (76.2 mm) anti-aircraft gun aft. Some ships were fitted with six- or three-pounder guns in lieu of the twelve-pounder. Ships that served in the Second World War initially had two machine guns installed in the bridge wings. Later the four-inch gun was replaced by another twelve-pounder and the machine guns were replaced by Oerlikon 20 mm cannon. Later still another pair of Oerlikons was mounted in the stern.

Construction and career
She was originally to be named Dawlish, but was renamed before launch to avoid possible misunderstandings of having vessels named after coastal locations.