After some interference by real life (I was surprised I still had one) now presenting:
Thiarian Submarines of the Second World War:
1. Political conditions
The Treaty of Norfolk stipulated a complete ban on the possession of submarines for the Thiarian Navy. All existing units had to be handed over to the Allies. Unlike the German submarine arm, Thiaria’s Silent Service had never been a significant menace for the Allies; their boats had followed the French lead into all kinds of bizarre technical dead ends, and their doctrine to use the submarine fleet as an auxiliary force for the main battlefleet, to be employed against enemy warships only, was fundamentally faulty. Thus the loss of the submarine force was not considered crippling, especially as the surface fleet was treated a lot more kindly than the German one and was allowed to retain several high-end battleships and cruisers. During the early 1920s, little if any thought was wasted on a possible revival, and the Navy actively strove to get rid of former submariners in order to retain more experienced surface ship personnel. By 1928, Thiaria’s submarine fleet was well and truly dead. But when the world economic crisis allowed for rapid payment of the remaining reparations to Brazil and Patagonia, Thiaria suddenly faced the prospect of re-emerging as a fully accepted member of the international Naval Powers club, especially as the country was less affected by the depression than virtually anyone else and threatened to launch an uncontested building programme unless it was integrated in the international Naval Treaty system. When the Thiarians finally signed LNT 1 in 1930, they were allowed to rebuild a submarine force under the same restrictions that applied to anyone else; the treaty ruled out subs of more than 2.000 tons displacement, but made no provisions about numbers of smaller ships. Early in the following year, construction of a large, modern naval submarine yard was started at An Trionaid, which also became home of the submarine school, and all established naval bases received submarine repair facilities.
2. Searching for the ideal types
The future submarine requirements of Thiaria were already formulated before the treaty was signed. The Admiralty had identified a requirement for three basic types: Coastal submarines of 500 - 700 tons, submarine minelayers of 750 – 900 tons and cruiser submarines of 1400 – 1600 tons. The cruiser submarines were to be employed primarily against soft targets – meaning enemy merchant shipping – in the South Atlantic, the South Pacific and the Indian Ocean; the minelayers were to attack enemy bases in the South Atlantic; and the coastal submarines were for training and home defence. Interestingly, the Thiarians initially were not interested in medium-sized oceangoing submarines. 20 of each type were to be acquired as a minimum. As Thiaria had no recent experience in submarine construction, foreign samples were to be procured in order to find an ideal combination of capabilities for the development of home-grown submarines.
To quickly establish a submarine training routine – there was virtually no one in the Thiarian Navy with submarine operations experience more recent than a dozen years in 1930 – negotiations with the USA for the acquisition of two used S-class submarines were opened late in 1930. As the Americans were about to get rid of some of their technically less satisfying subs at that time, they happily offered four ‘Government-type’ S-class boats, the S3, S6, S8 and S9, which were due to be retired in 1931 anyway, for sale. They had seen little strenuous use, but were considered inferior to the ‘Electric-Boat-type’ and phased out by the USN to ensure full commonality of all remaining S-boats. They were transferred to the Thiarian Navy in late 1931 and commissioned as LT Caladbolg, LT Claiomh Solais, LT Arcadbhar and LT Gae Assail; these were the names of magic weapons of Celtic mythology.
These boats were only employed for training. They were generally considered as rather shabby pieces of workmanship (a view shared by the USN about the Lake- and Government-type S-boats) and frequently broke down. They were however invaluable in providing the Thiarian navy with a new generation of submariners. Their 533mm tubes were used till the supply of US-sourced 533mm training fish was depleted; they were then converted to 450mm tubes in 1937/8, which were good enough for training. Claiomh Solais and Gae Assail were converted to underwater targets in 1939; the latter was torpedoed and sunk during an exercise in 1941, the former remained in service in this role till 1943, when she vanished during a routine dive without enemy contact. The wreck was found in 1963 during offshore oil surveys, salvaged and scrapped. Caladbolg and Arcadbhar soldiered on as training vessels throughout the war; both were among the first Thiarian ships to join the rebellion against the Murchada regime. Caladbolg was scrapped in 1947 and Arcadhbar in 1949.
Two coastal submarines were ordered in the Netherlands under the 1931 estimates; these were closely fashioned on the O12-type which was just commissioned into the Dutch Navy. They however lacked the one feature their Dutch demi-sisters were particularly well known for, the retractable 40mm AA guns; Thiarian subs were expected to operate under poor weather conditions in the open sea and the air threat to them was considered negligible – an attitude which would prevail for years until painfully proven wrong by the advent of large numbers of allied escort carriers. Instead, they were fitted with a LA 75mm gun in front of the CT, mostly for training purposes. At this time, the limitation of AA capabilities to a single 13mm MG was not considered a disadvantage given expected operating conditions for these subs; they were also considered more stable than the Dutch originals. They were built by the De Schelde yard between 1931 and 1932 and delivered late that year and early in 1933, respectively. They were named Beansi (Gaelic: Banshee) and Puca (Gaelic: Imp), continuing the WW1 tradition of naming submarines after mythological creatures. They established their unsuitability for South Atlantic conditions as early as on their delivery cruise; Puca nearly sank in a severe storm, and Beansi also suffered considerable sea and weather damage.
On the other hand, both subs proved mechanically reliable, were very quick divers and featured many innovative detail solutions. They were used as training boats throughout their careers. Both were commissioned without hydrophones, but were retrofitted with them in 1937/8, when they had their bow rebuilt to provide better seakeeping; in late 1941, they also received ASDIC in a retractable pod amidships.
Neither ever went on a combat cruise. Both survived the war, but were pretty much used up; they were scrapped in 1947 and 1953, respectively.
Under the 1931 estimates, two further coastal submarines were ordered from the Normand Yard in France in order to compare French to Dutch design practice. The boats were identical to the French Diane-Class (630-tonnes type) and received the names Siofra (Elf) and Siog (Fairy). They were delivered late 1934 and early 1935, respectively, and much larger than the Dutch boats; their surface speed was higher, the submerged speed was less. They were also considered less reliable and – having been designed primarily for use in the Mediterranean Sea – were no better as sea boats; as with the Dutch boats, this was mostly a result of their limited size.
They were however found quite habitable, and the Thiarians also liked their relatively high submerged speed, which partly resulted from their carefully streamlined CTs, which the Thiarians would adopt for virtually all their home-built submarines. Their French-style rotating twin torpedo set aft was however soon considered useless in service and removed from both in 1940, when they received hydrophones. ASDIC and a passive radar warning antenna were retrofitted in 1942, and radar late in 1943.
Like the other 1930 and 1931 boats, the Siofra-class was used exclusively for training; their low surface speed and short range made them unsuitable for the far-ranged operations of the Thiarian submarine force. They also had a rather long crash dive time for their size (45 secs), which became a particular liability with the sharp increase of the air threat after 1942. Both survived the war and were used as floating generator stations till the late 1950s, then scrapped in 1959 and 1961, respectively.
2.4. Meadail-class (Batch 1)
These submarine minelayers were the first Thiarian submarine class which was not an off-the-shelf foreign design, although the first two of this four-ship class was ordered abroad. When the Thiarians had to decide upon their first minelayer type in 1931, the French had just commissioned their first Saphir-class minelayer, which was widely regarded as a particularly good design; as neither the USA nor the Netherlands offered any minelayers at that time, the Thiarians had little choice (Germany was not yet building submarines, Japan was not exporting any and Italian submarine technology was considered inferior). As the Saphir-class was doubtlessly very slow (12/7 knots), the Thiarians did not adopt it as it was, but ordered two units of a lengthened version at the Schneider Yard at Chalon-sur-Saone; these had considerably stronger engines for a speed of 16/9 knots and also somewhat longer range (8.000 nm at economic speed). Their bow section was modified to take four rather than just two torpedo tubes. They carried 32 mines in 8 vertical tubes along their sides and ten torpedoes (two of them in the external mount aft; they also had a 75mm gun and two 13mm AAMGs. Diving depth was only 75m, but due to the very nature of their mission, these minelayers would usually operate in shallow waters, so 75m was deemed enough. They were delivered in mid-1935 and early 1936, respectively, and named LT Meadail (Starfish) and Cuan Mara (Sea Urchin). They were the first Thiarian submarines with passive hydrophones on completion.
The contract included all plans and a production license, and two sister ships were ordered under the 1933 estimates from the CTS yard, which had established a good working relationship with Schneider. They were identical with the French originals and delivered in 1937 under the names LT Natalas (Nautilus) and Scuid (Squid). At slightly over five years, they had the longest construction time of all Thiarian submarines. The delays were due to the yard’s lack of experience, as these boats were the first Thiarian-built submarines since 1918. They were however well received by the Navy and did not significantly differ in performance from their French sisters; crash-dive time was 45 seconds, slightly slower than the smaller Saphir-class. The only difference between the French- and domestic built boats was the more modern and effective wireless rig of the domestically built boats; this was however retrofitted to the French-built units by 1939.
Although the class was not up-gunned during the war, the surviving units had received radar, a passive radar warning set, and IFF and ECM antennae by 1943; ASDIC was mounted since 1941/2.
The domestically built boats were used mostly for training and experiments. Both survived the war and even remained on the active list till their retirement without replacement in 1953 and 1954, respectively. The French-built boats, which were generally more reliable, went on active duty, at first along the Patagonian coast, later mostly against Brazilian ports. Cuan Mara was damaged by gunfire from two Brazilian sub chasers in 1943 and had to be scuttled; Meadail survived the war, but sank at her moorings through negligence during the civil war. She was salvaged in 1947 and scrapped.
2.5. Dragun-class (Batch 1A)
The 1932 estimates included funds for two 1.500-ton cruiser submarines, which were ordered from the Loire yard in Nantes to the plans of the third batch of France’s Redoutable-class ‘Grand Patrol Submarine’. Upon delivery in early and mid-1936 – they were built unusually fast by French standards, in half the time of the French originals because of their higher price and Thiaria’s more regular and reliable rate payment, which made them the yard’s top priority – they were named LT Dragun (Dragon) and Nathair (Serpent). They differed in having more streamlined CTs than the French originals and one less trainable TT mount; instead, they boasted a second 100mm gun aft of the CT. Two 13mm MGs were available for the most basic air defence. Although they were none too maneuverable and needed almost a minute to dive, they were considered most satisfactory by the Thiarians; they were very good sea boats for submarines, had robust and tough double hulls, were habitable and reliable, and their speed of 20 knots surfaced and 10 knots submerged was world class, as was (at that time) their range of 12.000 nm at cruising speed – more than on the French boats because of more modern and efficient engines and slightly larger bunkers. Diving depth was 100 meters, and crash dive time however was a sluggish 60 seconds.
Both were in active service when the war started. Dragun became an early war loss in mid-1940 when she ran into a defensive minefield off Durban. Nathair was mostly employed in the Indian Ocean all the way to the Persian Gulf, although her kill tally was not really impressive. She was waterbombed and sunk by a Recherchean destroyer in May 1942. By that time she had received a newer wireless rig and ASDIC.
Although not very successful themselves, these boats were the ancestors of every large Thiarian submarine of the war.
By late 1933, it had become clear that the classical European coastal submarine, exemplified by the Beansi- and Siofra-classes, had no place in the Thiarian fleet. The smallest submarine that could operate effectively in the South Atlantic had to displace at least 1.000 tons surfaced, preferably 1.200, to achieve the necessary minimum of resistance against the prevailing weather conditions. Thus the 1934 estimates called for four such medium-sized oceangoing submarines. Two were ordered in the Netherlands, two in the USA from the Electric Boat Co. The latter were the last off-the-shelf submarines for the Thiarian navy; they were closely modeled after USS Cuttlefish, although they had a smaller CT. and a much stronger gun armament of two 100mm LA pieces. They were delivered in 1936 and named LT Nimfeach (Nymph) and LT Maighdean Mara (Mermaid).
Their novel features included a fully welded double hull – a feature which would become common for all wartime Thiarian submarines – and improvements in habitability, mostly by providing freshwater showers for the crew, air conditioning and unusally well laid out berthing and mess spaces. The early Torpedo Fire Control Computer fitted to the US original was however not part of the package; Thiaria would later develop a similar analogous system, but never catch up with the USN’s technical lead. At 10.000 nm, range of these boats was perfectly within specifications, but their speed (16 knots surfaced, 7 knots submerged) was considered insufficient, as was their crash dive time of 50 seconds. They also gave considerable maintenance troubles due to unnecessarily tight double hulls and unreliable diesels. Despite their doubtless strengths, they were not repeated for the Thiarian fleet. By 1940, both had been retrofitted with passive hydrophones and painted in Raider Blue, which was standardized for the submarine arm in 1938.
Both actively served in the war, mostly in the central Atlantic; Nimfeach racked up a kill tally of 87.000 GRT, making her the third most successful Thiarian submarine of the war. Both received the usual upgrades with ASDIC, ECM, IFF and active and passive radar.
Due to continuing engine troubles on both boats, Maighdean Mara was laid up in 1942 to be cannibalized in order to keep her sister running. Nimfeach survived the war, but was worn out in 1945 and nearly instantly scrapped.
The last foreign submarines delivered to the Thiarian navy were also ordered under the 1934 estimates from the Dutch De Schelde yard. They were modeled upon the Dutch O16, but received a larger diameter pressure hull, which was also slightly lengthened to retain the necessary length-width-ratio for high speed. Displacement was 1.150 tons surfaced / 1.500 tons submerged. The boats were delivered in 1937 and named LT Leipreachan (Leprechaun) and Clobhairceann (Clurichaun, another creature from Celtic mythology). They were as fine an example for the excellence of Dutch submarine design in the 1930s as any; the Thiarian Navy considered them the best medium submarine type worldwide, and they directly influenced the Dutch follow-on O19-class. Like the Beansi-class, these two much larger subs had a simplified turret compared with the Dutch original and two 100mm guns and two 13mm AAMGs instead of the 40mm AA guns on O16. Torpedo armament was less than on the Dutch boats: Four 559mm TTs forward and two aft, with two reloads for each forward tube and one for each aft tube (16 torpedoes total). The Thiarian boats also lacked a snorkel, which the Thiarians considered useless under South Atlantic conditions, where waves were nearly always so high that the engines would constantly get choked. They were reasonably good sea boats and attained nearly the same speed as the Redoutables: 19 knots on the surface and 10 knots submerged. Despite their greater power, their engines were much more reliable than those on the Nimfeachs. Range was the same 10.000 nm, but at a higher travel speed of 12 knots. They were quite maneuverable both above and below the surface and could crash dive in 35 seconds – not a world class figure, but still a lot faster than the Nimfeachs. At 120 meters, their test depth was considerably better than the 75 meters of the Nimfeachs. They were rated as habitable, although they lacked the extraordinary amenities of the Nimfeachs. They had passive sonar upon completion.
Unfortunately, Leipreachan became Thiaria’s very first submarine loss of the war; even more unfortunately, she sank by accident, rammed and cut in half by the minelayer LT Dibheirg. Clobhairceann received ASDIC and a more capable wireless rig early in 1941; she was mostly employed by the Thiarian Navy’s Special Forces for clandestine missions against Patagonia and later Brazil. During one such mission she stranded on an uncharted rock near Recife and had to be blown up to avoid capture. Her crew, remarkably, managed to board a Brazilian fishing trawler from their life rafts and get it to New Portugal.
Despite their early loss, these boats were immensely successful; it was they upon which Thiaria’s largest wartime submarine class was based, which in turn was considered one of the finest examples of the classical submersible prior to the advent of the true submarine in the shape of the German Type XXI.
Wartime series production to follow