Bjørgvin-class coastal defence ship

The Bjørgvin-class coastal battleships were ordered by Norway in 1912 to supplement the older Eidsvold and Tordenskjold-class coastal defence ships. The two ships laid down were compulsorily purchased by the British government for the Royal Navy when World War I broke out, and classified as monitors. The British government paid Norway £370,000 as compensation for each ship.

Bjørgvin as HMS Glatton
Class overview
Operators	Royal Navy
Preceded by	Eidsvold class
Succeeded by	None
Built	1912–1914
In commission	1914–1928
Completed	2
Lost	1
General characteristics
Type	Coastal defence ship
Displacement	4,900 long tons (4,979 t)
Length	94 m (308 ft 5 in)
Beam	16.8 m (55 ft 1 in)
Draught	5.4 m (17 ft 9 in)
Propulsion	Coal-fired reciprocating steam engines, 4,000 shp (2,983 kW)
Speed	15 knots (17 mph; 28 km/h)
Complement	305
Armament	2 × 24 cm (9.4 in) guns 4 × 15 cm (5.9 in) guns 6 × 10 cm (3.9 in) guns 2 × submerged torpedo tubes
Armour	Belt: 7 in (180 mm) Bulkheads: 4 in (100 mm) Barbettes: 8 in (200 mm) Turrets: 8 in (200 mm) Decks: 2.5 in (64 mm) Conning tower: 8 in (200 mm)

Ships in class

• Bjørgvin (1912) - Compulsorily purchased by the British government and renamed HMS Glatton, blew up in a September 1918 accident.
• Nidaros (1912) - Compulsorily purchased by the British government and renamed HMS Gorgon.

Description

The Bjørgvin class would be significantly more heavily armed than the previous Eidsvold class:

• Two 24 cm/50 guns, which in British service were relined to use standard British ammunition and became 9.2"/51.^[1] These were considered among the longest-ranged guns in the world in 1918. As designed, they would have fired a 190 kg (420 lb) projectile with a muzzle velocity of 884 m/s (2,900 ft/s), capable of penetrating 22.2 cm (8.7 in) of face-hardened armour at a range of 7,000 m (7,700 yd).
• Four 15 cm/50 in single turrets - one aft, one fore, two midships (one on either side). In British service they were relined to take standard 6 inches (15 cm) ammunition.^[2]
• Six 10 cm (3.9 in) guns.
• Two submerged torpedo tubes.

In addition to the heavier armament, the two ships of the Bjørgvin class were also significantly better armoured, with her armour better distributed:

• 7 inches (18 cm) thick armour in the belt
• 8 inches (20 cm) thick armour on the turrets
• 8 inches (20 cm) thick armour in the barbettes
• 2.5 inches (6.4 cm) thick armoured deck
• 8 inches (20 cm) thick armour on the conning tower
• 4 inches (10 cm) thick armoured bulkheads