The M29-class comprised five monitors of the Royal Navy, all built and launched during 1915.

The ships of this class were ordered in March, 1915, as part of the Emergency War Programme of ship construction. The contract for construction was granted to Harland & Wolff, Belfast, who sub-contracted the construction of the M29 and M31 to Workman Clark Limited.

Ships of the Class

• M29 - Launched May 22, 1915 and later renamed HMS Medusa , she was sold in 1946.
• M30 - Launched June 23, 1915 and sunk on May 14, 1916.
• M31 - Launched June 24, 1915 and broken up for scrap in 1948.
• M32 - Launched May 22, 1915 and sold in January, 1920.
• M33 - Launched May 22, 1915, she is one of only two World War I-era warships in existence today and is located in dry-dock near HMS Victory at Portsmouth Naval Base.

M29 class statistics

• Displacement: 535 tons
• Length: 170 ft (52 m)
• Beam: 31 ft (9.4 m)
• Draught: 6.75 ft (2.1 m)
• Complement: 75
• Armament:
  • 2 x 6 in (152 mm) guns
  • 1 x 6 pdr (3 kg) AA
  • 1 x 3 inch (76 mm) AA. for M31 and M33
• Speed: 10 knots (19 km/h)
• Propulsion: Triple expansion. Twin screws. Yarrow oil fuel 45 tons boilers. 400 hp (300 kW)