Bjørgvin-class coastal defence ship

WW1 Royal Navy monitors originally built for Norway

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 Royal Navy when World War I broke out, and classified as monitors. The British government paid Norway £370,000 as compensation for each ship.

Ships in class

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

Notes

1. British 9.2"/51 (23.4 cm) Mark XII, updated 8 April 2005, retrieved 9 December 2005
2. British 6"/49 (15.2 cm) BL Mark XVIII, updated 1 April 2005, retrieved 9 December 2005

References

• Model of KNM Bjørgnvin Archived 21 April 2005 at the Wayback Machine, from the website of the Norwegian Armed Forces Museum, retrieved 9 December 2005
• On guns, see Notes.
• Naval History via Flix: KNM Nidaros, retrieved 11 December 2005
• Naval History via Flix: Technical Details of Ship HMS Gorgon, retrieved 9 December 2005

External links

• Model of KNM Bjørgnvin^{[permanent dead link]}, head on view
• Details of the forecastle Archived 29 September 2004 at the Wayback Machine and details of bridge Archived 14 July 2004 at the Wayback Machine.
• The loss of the HMS Glatton, an "interesting little ship", retrieved 15 January 2007