Thiaria signed the second London Naval Treaty in 1936 which lifted numerical restrictions on light cruisers, but stipulated a total ban on new construction of heavy cruisers for the signatories (except for the USN which had not even built its 180.000 tons from the first LNT). They immediately laid down two additional Oirirceas-class light cruisers. Approval of the Oireachtas for four further vessels - officially called 'improved Oirirceas-class' - was given in 1937, but at that time, the Thiarian government estimated that things were inevitably developing towards war. Abiding to treaties at such a time was considered naive, and the Thiarians sincerely expected no other signatory to do so either. The decision to revert to the construction of heavy cruisers was made as early as April 1937, and the design process was to be sped up by basing the new heavy cruiser upon the plans of the Oirirceas-class, of which the first ship was nearing completion. Three different pre-designs were prepared with varying degrees of similarity to Oirirceas; one of them was a straightforward upscale with virtually the same appearance, another one a flush-decked variant, and the third one reverted to two funnels. The decision to go with the single-funneled flush-decker was made in March 1938. The first two were laid down at the same yards that had just delivered Oirirceas and Ardcheim in May and August 1938, respectively; the CSCA order was named LT Caitriona (named for the battle where the Thiarians virtually annihilated the Brazilian fleet in 1917) and the ship laid down at the Nuatearman Naval yard was named LT Trionaid (named for a battle in 1807 in the middle of the Bauaine where seven ex-Spanish ships of the line, which had earlier been captured by Thiarian insurgents under Conaire himself, surprised a slightly smaller British squadron and soundly defeated it; this was the first ever naval engagement featuring an all-Thiarian fleet under Thiarian command). The second group was laid down in 1939, LT Noyalo (named for the Alamo-like defence of the French-built fortress at the seaside of the capital Carriolar against the British in 1807, conducted by the crews of the same ships that had won the battle of Trionaid a few weeks before) at the Boldisaire yard in Carriolar and LT Corcaigh (named for an engagement in 1815 where Thiarian privateers set seven British warships afire with fireships) at the Abernenui Naval Yard. The new cruisers thoroughly disregarded the WNT size limit for heavy cruiser in order to achieve a truly balanced ship; standard displacement as designed was 13.500ts, and even this generous figure was handsomely exceeded as completed. Their hulls - shaped as the Oirirceas-class, with bow bulbs, transom sterns and elaborate hydrodynamic lines - contained a three-shaft plant of 120.000hp, whose arrangement mirrored that of the Conlan-class battleships: one unit (a turbine set and three boilers) aft for the center shaft and two identical units for the wing shafts forward en echelon (with the port turbine in front of the boilers and the starboard turbine behind them); piping was provided for cross-feeding in case one of the units lost steam, and all uptakes were trunked together. Design speed was 33,5 knots, a conservative figure which was achieved in service even with dirty hulls; a continuous sea speed of 31 knots was easily secured. Three rudders were provided, one behind each propeller; their tactical diameter was rather large at 1.000 meters, though, a common fault with Thiarian ships, whose design never prioritized maneuverability. A complete 140mm belt (inclined 15°) and an armoured deck of 70mm over vitals (thinning to 30mm at the ends) provided protection against 203mm shells for the first time in Thiarian cruiser design; like the Oirirceas-class, they had no conning tower. The turrets had 180mm shields, 60mm roofs and 140mm upper barbettes, tapering to 80mm behind the belt. No torpedo bulkhead was provided (due to insufficient expansion space, such were considered useless on cruisers), but thorough internal compartmentalization. For the main armament, a new model 195mm gun of 60 calibers was introduced, which could fire a new type of shell 20% heavier than the original ones. At 126 kilograms, they were as destructive as any foreign 203mm shell, and the new gun had outstanding ballistic properties. As they used the same wedge breech than their predecessor model, they had the same excellent sustained ROF of one shell every 15 seconds (a burst rate of one shell every 10 seconds per gun could be kept up for a minute with a well trained crew). These guns bridged the firepower gap to every foreign 203mm gun except the US Mk.15, which had a super heavy shell of its own, weighing 152 kilograms, and clearly outperformed the Thiarian gun. Secondary armament consisted of ten 100mm DP guns of a new 60-caliber type which outperformed the old 45-caliber piece in every respect; these guns were second only to the Japanese 100/65 in performance, and the margin was rather slight. Six 37mm quads with half again the ammunition allowance as on the Oirirceas-class were installed, as were twenty 20mm cannon and eight 559mm torpedo tubes. The flight and boat deck arrangements were very similar to Oirirceas, but they had two aircraft cranes and the catapult on the centerline. Three planes were embarked. Caitriona was built in 40 months, Trionaid in 44, Noyalo in 50 and Corcaigh in 47. When Caitriona was completed in November 1941, she attained 33,7 knots on 121.000 hp (no forced flank power trials were run); Trionaid made 33,8 knots on 126.000 hp on her trials in May 1942. Caitriona had her action debut during the invasion of Uruguay, accompanying the Thiarian carriers. During the advance of the Thiarian army into Brazil, Caitriona repeatedly went close to the shore and shelled enemy positions at Cricriuma, Porto Allegre and Florianopolis. She came under air attack four times, but had fighter cover, and her powerful radar-guided flak accounted for ten enemy planes. She was joined by Trionaid in July. The first group looked like this upon completion:
After an unsuccessful venture into the central Atlantic, hunting for enemy shipping, which brought them nearly a thousand miles north of the equator and almost into the fangs of the British battleship HMS Africa, both accompanied the fleet on the Capetown raid, staying close to the carriers; they got no opportunity to engage the enemy. Britain's answer came swiftly in the Battle of Meanhchiorcal; Trionaid and Caitriona were present, but were no priority targets and got no enemies into their sights too. In October, both departed for the pacific and took part in the famous Panama raid. During the single engagement against a virtually undefended US convoy, Trionaid sank the escort flagship, an old coast guard cutter which put up a gallant, if ineffective fight (the distress call mentioned an attack by 'Japs'). Trionaid then proceeded to sink a transport, and her sister sank two of them. On the return leg, Trionaid fired her main guns at a submarine sighting, which was subsequently declared false; the USN however revealed in 1946 that USS Hoe actually went missing in that area at around that time. Ironically, these two kills would remain the only ones in Trionaid's career. During the raid, for which she had received eight additional 20mm cannon and updated communications gear, she looked like this:
After their return, both took part in the battle of Faoigabhar. In the initial phase of the battle, Caitriona ended a destroyer skirmish where three big Free French destroyers threatened to get the upper hand over their Thiarian adversaries; her 195mm guns sank Audacieux and damaged Malin. In the second half of the engagement, the Thiarians furiously attacked half a dozen large British ships which were still re-grouping after having hunted down and sunk two dozen Thiarian transports. Caitriona and four destroyers engaged the British light cruiser HMS Nigeria and sank her; Trionaid heavily damaged the heavy cruiser HMS Fife, which was finished off by Thiarian destroyers. Fife gave a furious fight, and Trionaid suffered fourteen 203mm hits, which pretty much wrecked her aft superstructure. While Trionaid was under repair, Caitriona took part in the last large Thiarian raid into the Indian ocean together with two older cruisers. They intercepted the enemy convoy as planned, and LT Ogleidhras managed to sink an escort carrier with gunfire, but the remaining British close escort group, although outnumbered and outgunned, gave the Thiarians a desperate fight. Caitriona damaged the light cruiser HMS Phoebe, which was then sank by Thiarian destroyer torpedoes, but was herself torpedoed by HMS Kingston, which was subsequently sunk by the Thiarian destroyer LT Praitinniuil. While this fight went on, the British convoy scattered, and all transports escaped. Caitriona then underwent repairs. While Caitriona and Trionaid were in dockyard hands, the third unit of the class, LT Corcaigh, joined the fleet in October 1943. Noyalo as the last unit of her class followed in December. They differed from their sisters by having an additional 37mm quad aft, and re-located 20mm cannon. They also were fitted with Kokoan-designed fast reload racks for their 559mm quad torpedo tubes (not visible, but the tubes had to be relocated forward), used 1943 pattern oxygene torpedoes and had a new generation of radars. During their repairs, Caitriona and Trionaid were refitted to the same standard (minus the fast torpedo reload racks). On her very first mission, Corcaigh accompanied a convoy to New Portugal and was critically damaged by British carrier planes, putting her out of service for half a year. Trionaid came back to service a few days after and joined the Thiarian carrier strike force. She took part in a naval air battle against a strong British fleet trying to pave the way for a tactical invasion behind Thiarian lines in Brazil in December 1943. A week after the battle, Caitriona was repaired, and in January, for the first time three of the class were simultaneously available. The second group looked like this when completed:
Noyalo's career was however almost cut short by the Brazilian submarine Arpao on February 25th with two torpedoes which ripped out her port shaft, cracked her keel (fortunately very far aft) and created nearly 2.000 tons of flooding. If she had not been close enough to the port of An Thuaidh to be towed inshore and beached, she would certainly have been lost. Corcaigh made it back into service just prior to the battle of Anfa Caolas. There Caitriona and Trionaid damaged USS Boise with gunfire, but had to let her escape when the Brazilian battleship Aquidaban came to her assistance after sinking the battlecruiser LT Conlan. Corcaigh accompanied the battleship LT Tirghra during her epic battle with USS Iowa and escorted the crippled battleship to Montevideo after Iowa had been sunk by LT Athartha. While the rest of the fleet returned to Thiaria, Corcaigh remained in Montevideo and was attacked by US and Brazilian airplanes five times, but determined fighter resistance and precise AA fire prevented damage. She embarked eight army-type 37mm single mounts for additional protection during her stay in Montevideo. After Tirghra had been patched up, Corcaigh escorted her back to Thiaria in July. Half way back, they came under attack by a Recherchean submarine, and Corcaigh was torpedoed thrice and sunk; 600 of her crew were rescued by Tirghra while two Thiarian destroyers chased the submarine off. This is what Corcaigh looked like at the time of her loss; she had been the first of her class to replace her air search radar with a more modern type:
In late July, Caitriona and Trionaid sortied against a major Recherchean sweep into Thiarian waters, which was repulsed; neither engaged enemy surface ships. Both cruisers remained inactive during the initial phase of the Thiarian civil war. Their crews did not join the rebelllion, but Commodore Eachthiarn, their division commander, kept finding excuses for not committing any of his men against the insurgents. After the loyalist attempt to board the mutinous battleship Tirghra ended in a bloody massacre, nearly all major units of the fleet went over to the rebels, including Caitriona and Trionaid. Noyalo was still docked and undergoing repairs; these ground to a halt after the armistice, and when a co-belligerent fleet for the pacific was assembled in 1945, only Caitriona and Trionaid were available. They received a similar refit as the other co-belligerent Thiarian vessels, including upgraded radars and a part replacement of 24 of her 20mm cannon by 12 additional 37mm guns, bringing the number of the latter to 44. They arrived in the pacific just in time for the battle of the Philippine Sea, where the surface fleets of both sides made no contact. This drastically changed in the battle of the Leyte Gulf in October; at that time, Caitriona and Trionaid looked like this:
During the clash between TF38.2, to which the Thiarian contingent was attached, and Kurita's center task force, Caitriona and Trionaid found themselves in the middle of a battleship slugfest, which would certainly have resulted in the loss of the Thiarian flagship Athartha if the Thiarians had not charged the Japanese and Kokoans with their entire cruiser and destroyer force, eventually succeeding in torpedoing the Kokoan flagship Nakamori and allowing Athartha to escape. To free the way for the destroyers, Caitriona, Trionaid and the heavy US cruiser St.Paul engaged five Japanese and Kokoan heavy cruisers. Although the wrath of the Japanese and Kokoans was primarily directed at St.Paul, which was sunk by 34 203mm shells and five torpedoes from Suzuya, Chokai and Maya, Trionaid was also quite shot up by the Kokoan Nintoku and Fujiwara. Her return fire damaged Fujiwara, which was subsequently finished off by planes from US escort carriers. Only Caitriona came out of that inferno with relatively few bruises, and her own precise fire damaged Maya so badly that the latter had to retreat and sank during the night. Caitriona also damaged the Japanese destroyer Murakaze, which was beached and later blown up by US carrier planes. Fortunately for the Thiarians, another US carrier battlegroup then hit the Japanese and sank or damaged so many of them that the battered remnants of TF 38.2's surface component could disengage. Trionaid and Athartha then returned to Hawaii, after both had taken very severe punishment; Caitriona was granted the right to represent Thiaria in Tokyo Bay for the Japanese surrender together with the battlecruiser Caithreim. After their return to Thiaria, both heavy cruisers were laid up awaiting their fate. The peace of 1948 left only light cruisers to the Thiarian fleet, and all three Caitriona-class vessels became allied prizes. Noyalo, still unrepaired, was ceded to the USA and expended during the nuclear tests in the Bikini atoll. Caitriona went to the British and was scrapped in 1951 after some trials. Trionaid was awarded to the Soviet Union and transferred to Vladivostok in August 1949 under her own power to be refurbished in the Dalzavod yard and become flagship of the Soviet Pacific fleet. Her damage from Leyte had not been thoroughly repaired, and her watertight integrity was only threadbare; her inexperienced Soviet crew had only received a short crash course in operating her. To nobody's surprise - especially not the American supervisors who had looked away when Thiarian yard personnel had sabotaged her leak pumps - Trionaid came only as far as Cape Hoorn and sank in a severe southern hemispheric winter storm.