Dian Cécht-class battleship

Class overview
Name:	Dian Cécht-class battleship
Operators:	Royal Ossorian Navy
Preceded by:	Luchtaine-class
Succeeded by:	Arduinna-class
In commission:	1920 - 1949
Planned:	6
Completed:	6
Retired:	6
General characteristics (1937 refit)
Type:	Battleship
Displacement:	33,143 t standard 36,137 t full load
Length:	192 meters
Beam:	27 meters
Draught:	10 meters
Propulsion:	18 x oil-fired boilers 4 x geared turbines 2 x screws
Speed:	21 kts
Range:	7,000 nm at 10 kts
Complement:	1,327
Armament:	8 x dual 380 mm/45 caliber guns 14 x twin 150 mm/45 caliber casemate guns 32 x quad 40 mm/55 caliber anti-aircraft guns 30 x single 20 mm/70 caliber anti-aircraft guns 6 x submerged 533 mm broadside torpedo tubes
Armor:	Belt: 300 mm Deck: 150 mm Gun: 250 mm Barbette: 250 mm Bulkhead: 200 mm Conning tower: 200 mm

The Dian Cécht-class was a class of six battleships built for the Royal Ossorian Navy starting in 1916. The class comprised of the ships Dian Cécht, Cernunnos, Airmid, Mórrígan, Epona, and Rosmerta. A variant of the Dian Cécht design was ultimately used as the basis for the Areadbhar-class battlecruisers built a few years later.

Design

General characteristics

The Dian Cécht-class ships were 192 metres long overall, had a beam of 27 m and a draught of 10 m with a normal displacement of 30,539 t. The ships were powered by two screws powered by four turbines driven by steam provided by 18 oil-fired boilers. The engines were rated at 40,000 shaft horsepower and delivered a top speed of 21 knots. Dian Cécht and her sisters were capable of a maximum range of 7,000 nautical miles at a cruising speed of 10 knots.

Armament

The Dian Cécht-class ships mounted a main battery of eight 38 cm breach-loading guns mounted in four two-gun turrets placed in two superfiring pairs fore and aft of the superstructure ("Beith" and "Luis" turrets forward and "Saille" and "Nion" turrets aft). The gun housings allowed for the guns to depress to −5° and elevate to 30°, and while capable of being loaded at any angle, the guncrews typically returned them to +5 degrees, as the guns could be cleared faster at that elevation. The gun turrets could train 150° in either direction from the centreline. The guns could fire 875 kg shells at a rate of approximately 1.6 rounds per minute, and were capable of firing a variety of shells. At their maximum elevation of 30°, the guns had a range of approximately 30,000 m.

The secondary battery consisted of twelve 15 cm guns mounted in casemates in the hull around the upper superstructure. This placement was selected to limit the flooding problems seen with both the Taranis-class and Luchtaine-class battleships. These guns fired 45 kg shells at a rate of approximately 5–7 per minute. The guns could elevate to 15°, which enabled a maximum range of 12,400 m.

Armor

The Dian Cécht-class ships had a main armor belt that was 300 mm thick in the central area of the ship (covering the ammunition magazines, machinery spaces, and other vital parts of the ship). The belt tapered down to 150 mm towards the bow and stern. The main gun turrets were 250 mm on the sides and 75 mm on the rear, where shells were less likely to hit. The barbettes in which the turrets sat were 250 mm thick. The ships' armored deck was 125 mm thick.

Ships

Ship	Namesake	Builder	Laid down	Launched	Commissioned	Fate
Dian Cécht	God of Healing	HRM Dockyard, Gabhrán	1920	1921	1924
Cernunnos	God of Wilderness	HRM Dockyard, Thiar	1920	1921	1924
Airmid	Goddess of Medicine	HRM Dockyard, Cléire	1920	1921	1924
Mórrígan	Goddess of Warfare	HRM Dockyard, Thiar	1921	1922	1925
Epona	Goddess of Animals	HRM Dockyard, Gabhrán	1921	1922	1925
Rosmerta	Goddess of Fertility	HRM Dockyard, Cléire	1921	1922	1925