fighting ships of the world



M29 monitors (1915)

M29 1915

Name No Yard No Builder Laid down Launched Comp Fate
M29, 12/1925 - Medusa   485 Harland & Wolff, Belfast 3/1915 22/5/1915 6/1915 minelayer 1/1925, repair ship Talbot 9/1941
M30   486 Harland & Wolff, Belfast 3/1915 23/6/1915 7/1915 sunk 14/5/1916
M31, 12/1925 - Melpomene   487 Harland & Wolff, Belfast 3/1915 24/6/1915 7/1915 minelayer 1/1921, torpedo instruction vessel 9/1939
M32   488 Workman Clark, Belfast 3/1915 22/5/1915 6/1915 sold 1/1920
M33, 12/1925 - Minerva   489 Workman Clark, Belfast 3/1915 22/5/1915 6/1915 minelayer 2/1925, boom defence workshop 11/1943


Displacement normal, t


Displacement full, t


Length, m


Breadth, m


Draught, m

1.80 deep

No of shafts



2 VTE, 2 boilers

Power, h. p.


Max speed, kts


Fuel, t

45 oil
Endurance, nm(kts) 1440(8)

Armour, mm

gun shields: 152


2 x 1 - 152/45 BL Mk XII, 1 x 1 - 57/40 6pdr Hotchkiss Mk I



Ship project history: Just after the 234mm monitors had been ordered, Queen Elizabeth class were instructed to land their main deck 152mm guns. As only two could be resiled in each ship there were 10 Mk.XII guns available, so a slightly modified version of the M15 design was drawn up, armed with 2 single 152mm guns. The 7t gun could range to 13.4km at 17.5 elevation, and the total weight of gun, mounting and ammunition came to only 62t as against 100t for the 234mm guns. Using these approximate figures it was unwisely assumed that both displacement and draught could be scaled down by 18%, as compared with the M15 hull. This was unfortunate as the designers had overlooked the need to provide sufficient deck area for two guns, and if the deck area could not be reduced the hull dimensions could not be reduced either. The result was a ship which bore no relation to her legend displacement of 355t and designed draught of 1.2m. However, this alarming discrepancy did not affect them too badly, apart from a tendency to trim by the head which made steering difficult. Although the ex-Queen Elizabeth class guns were the basis for the design the guns actually allocated to the monitors turned out to be new construction mountings from COW and most barrels came from Vickers.

Protection: Only guns had armoured shields.

Modernizations: 1919, M31, M33: - 1 x 1 - 57/40; + 1 x 1 - 76/45 20cwt QF Mk I

1/1921, Portsmouth DYd, M31; (9/1923-1/1925, Devonport DYd), M29, (5/1924-2/1925, Pembroke DYd), M33: as minelayers without artillery, can carry 44 mines.

Naval service: M30 was sunk by Turkish coastal batteries off Smyrna 14/5/1916.

Many thanks to Wolfgang Stöhr for additional information on this page.

M29 1915


Ivan Gogin, 2008-14