History
United Kingdom
Name	HMS M30
Builder	Harland & Wolff, Belfast
Yard number	486
Laid down	March 1915
Launched	23 June 1915
Completed	9 July 1915
Fate	Sunk by shore batteries Gulf of Smyrna 14 May 1916
General characteristics
Class and type	M29 class monitor
Displacement	580 tons deep load
Length	177 ft 3 in (54.03 m)
Beam	31 ft (9.4 m)
Draught	5 ft 11 in (1.80 m)
Propulsion	Triple expansion. Twin screws. Yarrow oil fuel 45 tons boilers. 400 hp (300 kW)
Speed	10 knots (19 km/h)
Complement	72
Armament	2 × BL 6-inch (152.4 mm) Mk XII guns 1 × 6-pounder AA
Armour	6 in on gun shield

HMS M30 was a Royal Navy M29-class monitor of the First World War.

The availability of ten 6 inch Mk XII guns from the Queen Elizabeth-class battleships in 1915 prompted the Admiralty to order five scaled down versions of the M15-class monitors, which had been designed to use 9.2 inch guns. HMS M30 and her sisters were ordered from Harland & Wolff, Belfast in March 1915. Launched on 23 June 1915, she was completed in July 1915.

Upon completion, HMS M30 was sent to the Mediterranean. Whilst enforcing the Allied blockade in the Gulf of Smyrna, HMS M30 came under fire from the Austro-Hungarian howitzer battery 36 supporting the Turkish, and was sunk on 14 May 1916.

• Dittmar, F. J. & Colledge, J. J., "British Warships 1914-1919", (Ian Allan, London, 1972), ISBN 0-7110-0380-7
• Gray, Randal (ed), "Conway's All the World's Fighting Ships 1906–1921", (Conway Maritime Press, London, 1985), ISBN 0-85177-245-5