[3] The NS class airship was developed in response to the increasing requirement of the RNAS to carry out long-range anti-submarine patrols and convoy escort duties off the west coast of Great Britain, though its name came from the fact that the type was intended to work in collaboration with the Grand Fleet which mainly operated in the North Sea east of the British Isles.

[1] Similar to the Coastal and C-Star classes, the "North Seas" employed a tri-lobe envelope based on the Astra-Torres design principles.

[5][8] In addition to the radio equipment, the wireless operators' compartment carried Aldis lamps as well as international maritime signal flags.

[8] The type was initially fitted with a pair of 250 hp (190 kW) Rolls-Royce Eagle engines mounted one either side of the power car in streamlined enclosures.

Similar to the Coastal and C-Star class airships, one gun was mounted on a platform on top of the envelope which was reached through a climbing shaft.

Minor snags encountered during flights over the next few weeks were ironed out, and it was then decided to carry out a full-scale endurance test taking place on 5 June.

N.S.5 set off for East Fortune on 12 December, but both engines failed within sight of her destination, and she drifted with the wind for about 10 miles (16 km) before they could be restarted.

[1] Mainly due to the lack of a suitable alternative, official interest continued in the NS class despite the early reliability problems and the loss of two examples during their first months of service, and a further six were subsequently ordered in November 1917.

[1] Under the continuing command of Captain Wheelwright and with Admiralty officials on board, N.S.3 successfully completed test flights on 11 March 1918, and the following day she undertook an eight-hour trial whilst maintaining a speed in excess of 60 mph (97 km/h).

Subsequently, numerous requests to start operational duties were submitted to the Admiralty, and on 3 April permission was granted for a three-quarters power duration flight over land.

N.S.3 flew from Longside to Kingsnorth and back to East Fortune; a journey of 816 miles (1,313 km) in 22 hours which at the time constituted a record for British airships.

During a flight on the night of 31 May / 1 June whilst participating in the testing of the anti-aircraft capabilities of the Grand Fleet and shore batteries near Rosyth, N.S.3 achieved a height of 10,000 ft (3,000 m) – another record for the type.

The tests were initially successful reaching speeds of almost 20 knots (37 km/h), and on the final run N.S.3 touched down on the sea to exchange two officers from Vectis for two of N.S.3′s crew.

[3][9] Under the command of Captain W. K. Warnford N.S.11 set an early endurance record of 61 h 30 min, and accompanied by N.S.12 made the first airship journey to Norway.

In the early hours of 15 July on what was officially supposed to be a mine-hunting patrol, she was seen to fly beneath a long "greasy black cloud" off Cley next the Sea on the Norfolk coast and a massive explosion was heard shortly after.

[14] The extended endurance flights and records broken were simply the result of normal operational flying routine while escorting convoys, hunting for submarines and performing other duties with the Fleet, and due to their success in modified form they were regarded as being probably the best large non-rigid airship that had been produced by any country.