Iya class battleships:
Nusantara’s participation in the Washington Naval Conference of 1921-22 was the direct result of a Japanese plan to stifle her long-time rival’s naval expansion which was now perceived as a threat to the Empire’s ambitions in the Pacific – albeit a lesser one than posed by the United States or Britain.
However, these efforts were derailed at the conference itself. Japan immediately pushed for Nusantara to have parity with France and Italy at a ratio of 1.7, whereas the US and the UK wanted Nusantara to have parity with Japan. After weeks of heated debate a compromise was reached; Nusantara was allowed a ratio of 2.3, which equaled 244,000 metric tons for capital ships compared to Japan’s allowance of 320,000 metric tons. However, the big win for Nusantara was the provision allowing the country to complete the
Lewotobi class, which was currently under construction, in order to meet treaty limits, which of course did nothing to mollify the Japanese and further strained already poor relations with Nusantara.
After the so-called “building holiday” established by the Treaty expired in late 1931, the Nusantaran Admiralty issued specifications for a new class of battleship to replace the
Kerinci class battleships and the now thoroughly obsolete
Toba class semi-dreadnoughts which were nearing their twentieth year in service and thus eligible for replacement. A number of designs were created between 1932 and 1934 in keeping to the Treaty displacement limits of 35,560 metric tons armed with eight to twelve 343mm (13.5”) guns. The Admiralty wasn’t satisfied with these designs, however, as Japan already fielded two battleships with 16” guns and eight with 14” guns. New specifications were issued in 1935 for ships with a heavier main battery.
As it transpired, the solution was already at hand. Back in 1920, as work began on what would be the
Lewotobi class, the KNM purchased several British 15” Mk I guns originally intended for now-cancelled members of the
Queen Elizabeth and
Royal Sovereign classes as evaluation weapons. As part of this process, the Nationale Bewapeningswerken (National Armament Works or NB) took one of the guns and over-bored it to 393mm (15.5”), designating it the 393mm/40 Mk I. Work had continued on this weapon and by 1935 the NB was confident a 45-caliber variant could be produced to arm the new ships.
This revised program hit a snag when Nusantara, along with the US, Britain, and France, signed the 1936 London Naval Treaty which maintained the Washington Treaty 35,000 ton displacement limit, but also limited maximum gun size to 14” (356mm), which required another revision to the design by swapping the proposed 393mm’s for up-rated 343mm/50 Mk III guns. This change delayed the start of construction until late 1937. However, Japan’s refusal to sign the 1936 London Treaty triggered the escalation clause allowing up to 16” (406mm) guns. Nusantara immediately swapped out the planned quad 343mm turrets for triple mounts with the new 393mm/45 Mk IV – made possible when the designers, suspecting the Japanese wouldn’t sign the treaty, ensured the turret base rings were the same diameter for both mounts (a similar change occurred in the US when the 14” guns intended for the
North Carolina class were swapped for new design 16” weapons).
The first ship in the class,
Iya, was laid down in October of 1937, followed by four sister-ships;
Talakmau, Masurai, Kunyit, and
Imun, over the next two years.
Iya and
Talakmau were in service when war with Japan broke out in July of 1941, and
Kunyit commissioned by early 1942. Construction had lagged on the other two ships as war approached however, and both were cancelled in December of 1941, soon after broken up on the slipways to free up space for the Emergency Carrier Program. Commissioned initially without radar and with an outdated battery of 75mm AA guns, the three ships completed were quickly equipped with British radars, fire-control systems, and modern license-built 40mm and 20mm anti-aircraft weapons.
The
Iya class, although slightly outgunned by the Japanese
Nagato class and severely outgunned by the
Yamatos’, nevertheless gave a good accounting of themselves.
Talakmau was lost in April of 1943 to an air-strike from the Japanese carriers
Shokaku and
Zuikaku off Formosa, but
Iya and
Kunyit, although damaged on several occasions, survived the war.
Kunyit’s crowning moment was undoubtedly in August of 1945 when, along with the newer
Ijen, she fought the
Yamato off Okinawa. By approaching from opposite sides of the Japanese giant and keeping the range open, the two Nusantaran battlewagons showered the
Yamato with over a hundred 393mm AP and HE rounds, which, although failing to sink her, severely damaged the superstructure, fire-control gear, most of the secondary battery, and wrecked the funnel uptakes and several boilers, forcing the crippled battleship to be taken under tow. Both Nusantaran ships were damaged in the encounter -
Kunyit severely - but were later repaired and returned to service.
Yamato would be torpedoed and sunk two days later by the
Cavalerie (O-162), a
Jimpul class submarine, before she could reach Japan.
After the war ended in September of 1946, the
Iya class continued in active service until placed in reserve in 1962.
Iya was scrapped four years later, but
Kunyit became a museum ship and can still be visited today.
In class: (3+2)
Iya, Talakmau, Maurai (cancelled incomplete 1941, scrapped),
Kunyit, Imun (cancelled incomplete 1941, scrapped)
Built: 1937-1942
In commission: 1940-1962
Displacement: 35,200 ts standard, 38,820 ts full load
Dimensions: Length (o/a) 225.0m, length (w/l) 220.0m, beam 32.5m, draft (normal) 9.5m
Propulsion: 4-shaft, 4 x SKR geared turbines, 16 x HeV oil-fired boilers; 94,500 shp
Performance: 27.0 knots
Range: 12,000 nm at 12 knots
Armor: Belt 350mm tapering to 100mm ends, deck 145-120mm, main turrets 380-200mm, main barbettes 360mm, secondary turrets 50-25mm, torpedo bulkhead 30mm, forward conning tower 350mm, aft conning tower 50mm
Armament: 9 (3 x 3) NB 393mm/45 Mk IV, 16 (8 x 2) NB 114mm/45 Mk II; original AA battery: 8 x NB 75mm HA Mk VII; AA battery by January of 1945: 60 x NB 40mm AA Mk I (8 x 4, 14 x 2), 48 x NB 20mm AA Mk I (6 x 4, 12 x 2); 2-3 Royer V1R Meeuw scout floatplanes (replaced by 1944 by Royer V3R Albatros)
Sensors/Electronics: Type 273 surface-search radar, Type 277 air/surface search radar, Type 281 air-search radar, 2 x Type XX 5-meter fire control directors; 4 x Type A-III (license-built British HACS) anti-aircraft fire control directors
Crew: 1,338-1,750
Cheers!
Stealthjester