Taksin class cruiser (1939)

Thai Light Cruisers (1938-43): HTMS Taskin, Naruesan.

Thailand Day ! A first post about very special cruisers…
The Taksin class are an interesting “what if” in WW2 naval history. In the interwar Thailand started its own naval programme in order to become a regional power, and this comprised monitors, torpedo boats, submarines, sloops, minelayers, and even light cruisers. The latter were ordered in Italy in 1938 at CNT as the Taksin class. HTMS Taksin and Naresuan, were by far the most ambitious of the Siamese naval plan, destined each to lead their own battle group. They were started in 1939 in Trieste, but following the outbreak of the war construction stopped in 1941 (they should have been delivered by then and would have been likely involved in the battle of Koh Chang against the French, possibly even change the outcome). Instead, they were finally requisitioned by the Italian government to strengthen the Regia Marina. Renamed Etna and Vesuvio, they were practically in service when the armistice of November 1943 occurred. Thus, they remained certainly the most interesting “what-if” of that era.

The launch of Taksin of 28 May 1942.

Development

Context

Thailand in the 1930s went through very important events that impacted the naval side: The 1932 Siamese Revolution was by far the most important event of the decade. A group called the People’s Party carried out a bloodless coup that ended absolute monarchy and introduced a constitutional monarchy. King Rama VII (Prajadhipok) accepted the constitution but later abdicated in 1935, partly due to conflicts with the new political elite. King Rama VIII (Ananda Mahidol) became king at a young age and lived mostly abroad, so real power rested with military and civilian leaders. The decade saw frequent coups, unstable governments, and growing military influence, especially from figures like Plaek Phibunsongkhram.

The sole major cruiser of the Siamese Navy, Maha Chakri, until then.

In the society at large, there was a push toward modernization and nationalism with Western-style education and bureaucracy expanded, National identity became more emphasized over royal tradition. Social hierarchy began shifting away from strict royal dominance, though elites still held power. Urban Bangkok modernized faster than rural areas, which remained largely agrarian. Thailand remained however largely agricultural, with rice as its main export. The Great Depression affected Siam with falling rice prices hurting farmers, government revenue declined and economic nationalism began to grow toward the end of the decade, laying groundwork for later state-led development.

Foreign Relations saw a maintained independence unlike most of Southeast Asia with balanced relations between Western colonial powers, Britain and nearvy France but by the late 1930s, leadership increasingly admired authoritarian and nationalist models abroad, especially Japan. By 1939, the country officially changed its name from Siam to Thailand. The political tone shifted toward militarism, nationalism, and centralized control, setting the stage for Thailand’s role in World War II. With the arrival of Phibun as prime minister in December 1938 indeed, the regime became openly militaristic, and developed some fascist characteristics.

Towards a modern Thai Navy

The Monitor HTMS Sukhotai colorized by Irootoko Jr.

In 1925 the Siamese Navy, which only so far had a 1890s cruiser acting as Royal Yacht, Maha Chakri. A single destroyer was in service, Phra Ruang acquired in 1921 from Britain and receiving some modernization. There was also a gunboat, Chow Phraya, acquired in 1923 and the 1908 coast guard vessel Sriya Monton. But renewal started in 1925 with an order for two monitors to Japan to defend the coastline. The Ratanakosindra class was deliveredin 1929 and played an important role in 1941. More important were the Trad/Puket class Torpedo Boats ordered in 1934 to the Adriatic shipyards in Italy as the Kantan class Torpedo Boats, two Minelayers, as part of a giant contract with Italy. Of course the last ordered were the Taksin class cruiser at CNT. In addition in 1935 four submarines were ordered from Japan, the Sinsamudar class and two sloops (Tachin class), as well as torpedo motor crafts to Britain. Italy also formed personal in Thailand and enabled Bangkok DYd through a partnership with Montfalcone to build locally the Sarasindu class fishery protection vessels. Later the same yacht will start a serie of launches in 1941.

Order of the Taksin class

By far the largest and most ambitious of this modernization and expansion of the fleet, now officially the “Royal Thai Navy” to break with the Siamese dynasty traditions, was a pair of light cruisers that would be used as command ships of needed. Non-Japanese cruisers in Asia were not rare, except Colonial Powers. China, embroiled in a war from 1937, where most of its fleet was decimated, had before the largest cruiser fleet outside Japan, albeit ironically only two were modern a japanese-built. The remainder were pre-1911 revolution ships in various state of maintenance and preservation.

Thus, ordering two cruiser for Siam at the time was a bold move, destined to gain local naval parity. One potential adversary was France nearby in Indochina, with a fleet that was limited to a single light cruiser usually. The Thai Monitors, TBs, minelayers and submarines were mostly a way to counter agressions in home waters in a typical green water navy stance common to Scandinavian countries, but having cruiser would allow offensice cruises, notably a war on trade against colonial powers if needed. In 1934 the political orientation of the Government led to a rapprochement with Italy, and also for pragmatic cost reasons, looked for procurement there as local naval construction was quite limited. There was a modest shipyard at Bangkok that needed funding and expansion to produce warships, so a construction in Italy was the only way especially for a ship as large as a cruiser.

After the main order for small ships was passed in 1934 concerning 22 combat vessels, the largest procurement in Siamese History, in 1938 the new government under the PM Phibun decided to built ships that would give much stronger capabilities to the Navy and to lead if needed combat squadrons for various offensive operations. Planned to be delivered in 1941, they would be a game changer for the Nation, but also were a colossal investment. Ordered by the Siamese Navy from CRDA of Trieste after a review of proposals, and inspired by the British Arethusa class cruiser, they had the following initial characteristics: Total Length 153.8 meters, a beam of 14.47 meters, draught of 5.25 meters. Propulsion setup comprised three Boilers and two Parsons reduction geared steam turbine groups for 45,000 shp and 30 knots. It was to be armed with six OTO 152mm main guns in turrets, six 76 mm OTO DP guns and eiht 13.2mm HMG and well as six 533mm TTs and two aircraft, one catapult for a large array of operations. Protection was a bit above standard for a light cruiser at the time, 35 mm for the deck, 60 mm for the belt.

Design of the class

It was the first time CNT made export cruisers, but there was a precedent at Odero-Terni-Orlando (OTO Melara SpA later). That example was the pair of light cruiser for Argentina, the 21 de Mayo class. It can be argued as well as the Soviet Kirov class cruiser were largey an Italian design made in USSR largely inspired by the Duca d’Aosta-class. The 21 de May class were essentially “mini-trento” in design, and were armed by six twin 152 mm turrets, so about the same design.

However the Thai design was far more modern and included a taller, roomier hull. It was essentially a shrinked down Monteccuoli-class, loosing a whlole section aft plus turret, without the aft funnel and with torpedo tubes placed on the main deck forward sector, abreast turret no.1 to fired through two bulwark openings in the forecastle. This was a compromise for a serie of reasons, notably due to the location of the machinery combined with a shorter aft section.

Hull and general design

Taksin and Naresuan were named after historical Siamese warrior kings. The hull was as tall and wide as a Montecuccoli, had almost the same forecastle in proportions (albeit it was shorter), but lost about 30 meters of overall lenght amidship. It’s like the whole amidship section with its funnel was lost. Also, given the new proportions, stability concerns brough an easy choice for the three twin turrets: Only one would be on deck forward of the bridge and two aft, superfiring. Bith were constructed with a steel hull utilizing high-tensile steel for better durability and structural integrity.

The prow had a refined form but was straight down to the waterline, with a strong sheer above. The hull ended in a rounded and raked clipper stern reminiscent of contemporary Italian designs. Compared to other Condottieri-class cruisers, the Taksin-class was lighter and more compact, with a standard displacement half that of the Zara class and prioritized speed over protection, better suited for a trade war or to lead fleets of torpedo boats.

The final hull displaced 5,900 long tons (6,000 t) standard for an approximative 6,533 tonnes fully loaded, definitively light cruiser territory. The hull measured 153.8 m (504 ft 7 in) overall, 141 meters between parallel for a beam of 14.47 m (47 ft 6 in) and a mean draught of 5.95 m (19 ft 6 in). The ships had a planned complement of 580 officers and ratings.

Powerplant

The cruiser was given an “Italian” style steam powerplant with two shaft connected to Parsons geared turbines and three Yarrow boilers for a total output of 40,000 hp (29,800 kW). This was designed for a top speed of 28 knots (52 km/h; 32 mph). It seems that even through construction started practcally as the war erupted in August and September 1939, Italy was not at war with Britain or France before June 1940, so the machinery was delivered and the contract honored. Final top speed was re-evaluated from 30 to 28 knots (52 km/h; 32 mph). Despite having only one funnel, its machinery had en echelon arrangement, from a bow aft ward there were No.1 and 2 boiler rooms, No.1 engine room, No.3 boiler room and No.2 engine room).

Protection

The cruiser had a light protection given its size and status. The main deck above the machinery space just above the waterline had a steel plating with 35mm (1.4 inches) in thickness, that was located between the inner longitudinal splinter bulkheads. There was 20mm (0.8 inches) plating also between these bulkheads and the belt. The latter was the strongest part of the design, 60 mm (2.4 in) in thickness, extended from the front of N°1 barbette and the rear of N°3 barbette aft. Outer this belt the ship was completely unprotected. Between the Belt and armour deck there was thus an internal “box” protecting the essentials. Like the machinery, the ammunitions storage magazines were also inside this box. It is unknown if the wells up to the barbettes were also protected. There was no conning tower however it seems the fire control director atop the bridge had 60 mm armour according to some sources.

Armament

The original armament asked in the specifications was to be composed of three elements:

Six OTO 152 mm/57 Modello 1929(mod)

All in twin turrets, same as a Montecuccoli class cruiser. See the latter for more. In short, 7.22 t, with 6.682 m long barrel. The semi-armor piercing shells 50 kg (AP model 1926), or 47.5 kg (Mod. 1929 AP) and 44.3 kg for the high explosive (HE). Muzzle velocity 1000 m/s, max range 24.6 km (HE) or 22.6 km (m1929 AP) at +45° elevation.

Six 76 mm/40

Like the same Ansaldo M1917 found on Italian destroyers, sponsoned on three position per broadside amidship on deck. Not ideal fire arc to say the least.

Eight 13.2mm/76

These were set in two twin mounts Breda mounted on either the side of the bridge, two on deck at its foot and sponsoned and two higher up at on the rear platform mid-way to the bridge, close to the funnel. The arc of fire was better. Some sources suggested they could have been upgraded by 20 mm AA guns, also Breda.

Six 533mm TT

The quirkiest aspect of the design was the very unusual location of the torpedo tubes in two triple banks, in alcoves either side of the forward barbette, a very unlikely place. It is not known how much they could traverse nor their exact model and spare torpedoes carried. Taking a guess they could well be the Silurante 270/533.4 x 7.2 “M” Type (1930) by Napoli’s Silurificio Italiano. Weight: 3,748 lbs. (1,700 kg). Overall Length: 23 ft. 7 in. (7.200 m)Explosive Charge: 595 lbs. (270 kg)Range/Speed (3 settings):
4,400 yards (4,000 m)/46 knots
8,750 yards (8,000 m)/35 knots
13,100 yards (12,000 m)/29 knots

Air Group

Another oddity is the nature of the seaplanes that would have been mounted on the Taksin class cruiser. Rare drawings shows a CANT type biplane flying boat, like the CANT Z.504. In any case, the catapult was a large one located between the funnel and mainmast aft, with these aircraft recovered by the boom crane.

Old author’s illustration of the Conway’s reconstruction for the class from original blueprints or sketch (lost). The details of the bridge are shaky based on these, showing apparently a number of open wings.

⚙ Taksin class specifications
Displacement	5,900 long tons (6,000 t) standard
Dimensions	153.8 x 14.47 x 5.95m (504 ft 7 in x 47 ft 6 in x 19 ft 6 in)
Propulsion	2 shaft geared turbines, 3 boilers 40,000 hp (29,800 kW)
Speed	28 knots (30 knots planned)
Range	Estimated 5000 nm.
Armament	3×2 152mm/50 OTO, 3x 76 mm DP, 4×2 12.7 mm Breda AAn 2×3 533mm TTs
Protection	Belt 60 mm (2.4 in), Deck 20–35 mm (0.8–1.4 in)
Air Group	2 Floatplane (unknown)
Crew	580

Fate of the Taskin class

Taksin in construction a CNT on slip close to launch in 1942.

Taskin and Naresuan were laid down at Cantieri Riuniti dell’Adriatico in Trieste on 23 September and 26 August 1938, respectively and during construction by June 1940, Italy joined the war against the allies. By late 1941, close to launch for the cruisers, British aviation crippled merchants and escorts to North Africa so convoy escort soon concentrated focus of the Regia Marina. The need for dedicated AA cruiser became paramount just as the ASW protection was assumed by newly built corvettes. Thus, by December 1941, the Italian government requisitioned the two ships.

shipbucket profile, with the original green hull. Note the size of the original turrets.

This decision put an end to the contract and sums were reimbursed. But for Thailand this was a mild disaster. They obviously lacked during the battle of Koh Chang against the Vichy French Navy in April 1941. Two cruisers against one, Lamotte-Picquet could have completely returned the tables and end in a victory for the Thai Navy. Lost at sea, the battle was however won on land, and Thailand aligned itself strongly with Japan, which after December 1941 de facto occupied the country after it did with Indochina. In 1942-43 both cruisers might had been requisitioned by the IJN and put to their standards and likely sunk in 1944-45 by allied aviation anyway. In short, the dream of gaining local naval dominance was shatterred by WW2. Thailand will never have a new cruiser, but in the 1980s gained a better asset, its first aircraft carrier. Today, the Taksin class remains one of the most interesting “what-if” class of WW2. There is a model at the National Musem in Bangkok and numerous photos.

HTMS Taksin (ตากสิน)

Keel laying was on 23 September 1939 at CRDA Trieste. She was launched on 28 May 1942 and confiscated on 6 August 1942. Redesign led to a long completion time.

HTMS Naruesan (พระนเรศวรมหาราช)

Keel laying in 28 August 1939 at CRDA Trieste. She was launched much earlier than her sister on 6 August 1941, and confiscated on 6 August 1942. Redesign led to a long completion time.

The Italian Etna class

Graphic rendition of the Etna class as designed in 1942, with cutaway. Gli Incrociatori Italiani (Reddit)

As both had been launched, the first in August 1941, there was a long delay before the decision to takle them over was sanctions, and a lot of work already had been done. So, there was not much that the Italian designers could change. The torpedoes and catapult however were removed to make room for the new storage space as she was intended as an AA defence ship in convoy and transport herself. The large main guns were swapped for the much smaller, light, but more useful as a quick firing fual purpose, 13.5 cm (5.3 in)/45 modello 1938. They were located at the exact same barbettes and same arrangement.

The Anti-aircraft armament was completely modernized. It was fixed at ten single 6.5 cm (2.6 in)/64, all under shields, located on both decks on either broadside, two pairs on the forecastle abaft the deck structure and three pairs aft of the foredeck cut. The funnel shape was changed and the bridge completely remodelled with a new Italian fire control system topped by a Gudo radar. Instead of the mainmast aft there was a small pole mast immediately aft of the bridge, with wireles radio cables hanging to the low mini-mast immediately aft of N° superfiring turret. The superstructure freed from mast, boats and the catapult supported now four of the ten twin 2.0 cm (0.79 in) Breda guns. The remaining mounts were located in the bridge and two forward abaft N°1 turret.

The new deckhouse replacing catapult and hangar was now used as a deckhouse for troop accommodations. Indeed in total the Etna class were supposed to carry 1,000 soldiers. Four cargo holds near each gun could carry about of ammunition that were served by collapsible cranes. It was planned indeed to rebuild them as anti-air cruisers while their large hull would be redesigned to also carry cargo to Africa. Indeed, there were provisions for four cargo holds, a total of 600 cubic metres (21,000 ft3) in other sources, 450 cubic meters, notably with ammunition, integrated near the main armament positions, with large hatches and collapsible crane derricks to load supplies or personnel. This feature was quite unique to the Etna class after redesign.

⚙ Etna class specifications
Armament	3×2 135 mm/45 OTO M1938, 10× 65 mm/64 Terni, 10×2 20 mm/65 Breda
Crew	580+

Etna (ex-Taksin)

Vesuvio, originally ordered as Naresuan, was the first to enter construction at CRDA shipyard in Trieste, laid down on 26 August 1939, but yard priorities and rising wartime pressure saw a faster progression than anticipated, so she wa slaunched earlier on 6 August 1941 with most of her superstructure work, partial decking and framing, but still about one year worth of intense work before completion. She was eventually scuttled in September 1943.

Vesuvio (ex-Naresuan)

Etna was the former Taksin, intended as the lead ship and with provisions better fitting-out features at the same facility, laid down later on 23 September 1939 but resource allocation favored her sister. She was launched much later on 28 May 1942, under wartime secrecy protocols, no formal commissioning and still largely incomplete around 50-60 percent. By September the next year in 1943 the armistice of Cassibile was signed, and Italy surrendered to the Allies. Not much had been done with Etna being still 53% complete (63% allegedly for her sister). Both vessels were sabotaged by Italian workers under supervision top avoid capture by the Germans. Etna like her sister Vesuvio were scuttled in Trieste in 1945. The hulls were re-floated, scrapped in the late 1950s.

After the sabotage of September 1943, the incomplete, damaged hulls were seized by German troops and fell under the supervision of the Kriegsmarine at Trieste on 10 September. However since their completion did not matched any specifications and work to be done was still consireable, little to no work was done. As Allied forces advanced and the general retreat of axis forces to northern Italy in early 1945, the hulls were towed to be scuttle in the shallow waters of Trieste in the sunken in the attempt to block the port from use. Seized by the allies, they left them there. Only by 1946 and 1947, the Marina Militare made an evaluation and engineers determined that resuming construction in the new context. This was just not viable in Italy’s post war conditions, especiually with expected US help to rebuilt its Navy. Thuse, the hulls were stricken from register on 27 March 1947 and were laid up until dismantling proceeded from 1949.