LR Úrnua (IAC 1)

Class overview
Name:	LB Úrnua
Operators:	Royal Ossorian Navy
Succeeded by:	LB Nuálach
In commission:	1917 - 1944
Planned:	1
Completed:	1
Lost:	1
General characteristics
Type:	Aircraft carrier
Displacement:	20,000 t standard
Length:	240 meters
Beam:	27 meters
Draught:	8 meters
Propulsion:	18 x boilers 4 x geared turbines 4 x screws
Speed:	30 kts
Range:	5,000 nm at 15 kts
Complement:	737
Armament:	8 x 150 mm/50 caliber guns 6 x 100 mm/45 caliber guns
Armor:	Belt: 80 mm Deck: 40 mm Bulkhead: 100 mm
Aircraft carried:	10

LB Úrnua was the first aircraft carrier built by the Royal Ossorian Navy. She was converted from a battlecruiser while under construction towards the end of the Fourth Arzell War. Úrnua participated in comparative trials alongside the carriers Nuálach and Spreagtha to determine the optimum layout for aircraft carriers going forward, helping to influence RON design trends for the new type through the modern day.

Design

General characteristics

Úrnua had an overall length of 240 m, a beam of 27 m, and a draught of 8 m. She displaced 20,000 t at standard load. Each of the ship's four sets of geared steam turbines drove one 3-bladed propeller and were powered by 12 small-tube boilers and were rated at 90,000 shaft horsepower. This gave Úrnua a speed of approximately 30 knots. She had a range of 3,600 nautical miles at 10 knots.

Flight deck and hangar

The ship had two flight decks on either side of the superstructure; a forward flying-off deck and an aft landing deck. The flying-off deck was angled downwards slightly on the theory that this would help increase the speed of the aircraft, aiding it in taking off. Aircraft would traverse a narrow strip of decking around the superstructure and funnel to move between the fore and aft flight decks. The turbulence generated by the funnel and superstructure was so severe that only three successful landing attempts were made with the ship in this configuration. A series of crashes, with nine fatalities, prompted the Admiralty to forbid further landing attempts and the ship was ultimately retrofitted with a full-length flight deck. Aircraft were stored below the forward deck, and a crane was used to transfer aircraft between the flight deck and the storage area. The ship's aircraft capacity was 10 aircraft. The ship's crew totaled 737 officers and ratings.

Armament

For self-defense against enemy warships, Úrnua had eight 150 mm guns with each gun being allocated 150 rounds, and six 100 mm anti-aircraft guns with 200 rounds each.

Ships

Ship	Translation	Hull Number	Builder	Laid down	Launched	Commissioned	Fate
Úrnua	"Original"	IAC 1	HRM Dockyard, Cléire	1915	1916	1917	Sunk