Ships of the Nationalist and Republican Navies during the Spanish Civil War: Mar-Class Armed Merchant Cruisers

Both Mar Cantabrico and Mar Negro were freighters that were used by the Republicans to try to break the Nationalist blockade. The Mar Cantabrico was captured on 8th March 1937, and the Mar Negro was taken on the 1st September 1937. They were then extensively reconstructed at El Ferrol to become Armed Merchant Cruisers that were taken into service by the Nationalist Navy.

The Mar Cantabrico as a merchant ship.

The Mar Negro after conversion into an Armed Merchant Cruiser.

Ships' characteristics:

• Displacement: 6,632 tons
• Dimensions:
• Length: 421’ 7” (128.5m)
• Beam: 53’ 10” (16.4m)
• Draught: 34’ 2” (10.4m)
• Maximum Speed : 15 knots
• Armament: 4 x 5.9" (150mm) (4 x 1); 4 x 3.5" (88mm) (4 x 1); 2 x 2.25" (57 mm) (2 x 1) [Mar Cantabrico only]; 4 x 3" (76mm) (4 x 1) [Mar Negro only]; 3 x 0.79" (20mm) (3 x 1) [Mar Negro only]
• Complement: Unknown

Mar Cantabrico survived the Civil War and was re-converted to a freighter after the war. She was lost as a result of a fire in 1962.
Mar Negro survived the Civil War and was re-converted to a freighter after the war. Her fate after 1973 is unclear.