Yamagumo class destroyer (1965)

Japanese Self Defence Naval Force – Escort Destroyer (1966-2005): Yamagumo, Makigumo, Asagumo, Aokumo, Akigumo, Yugumo

The Yamagumo class were developed for the Japanese Maritime Self-Defense Force as six ship usually classified as a destroyer, but classed as destroyer escort given their nature, succeeding to the Akizuki class. They were planned as the new generation ASW workhorse of the fleet, with new generation weapon and sensors, notably the ASROC and OPS-11 early warning radar (Japanese AN/SPS-40). The next Minegumo-class tested DASH but the program failmed and a second batch of three was ordered of the Yamagumo, sometimes called the Aokumo class with some improvements in electronics (like the OQS-3 hull-sonar, same the AN/SQS-23) and AN/SQS-35 VDS. The first was laid down in 1964 and the last was completed in 1978, so they remained in service way past the end of the cold war, until 2005 for the last one. The lack of an ASW helicopter was their greatest limitation, but when combined with such external air support, they found their place in the JMSDF.

Development

The Yamagumo-class destroyer were developed for the Japan Maritime Self-Defense Force as the first dedicated ASROC platforms anti-submarine destroyer (The classification DDK was for escorts), with three ships first built in the 1962 plan, 2nd National Defense Programme, then the derivative Minegumo-class (40-42 DDK) plus three more under the 3rd, 4th National Defense Programmes. Thus, the first bacth (37-39 DDK) were considered the early model, and the second (44-49 DDK) a later model, sometimes referred to as the “Aokumo-class”. Construction cost for the first was 3.87 billion yen (1962).

When the First Defense Program was discussed, the JMSDF adopted a “high-low” mix and decided it wanted some fleet workhorses in order to build up the Navy within budgetary and equipment constraints, a situation well known by the USN post-Vietnam war that led to the design of the Spruance class. The combination of the Ayanami-class (30DDK) specialized anti-submarine warfare but with reduced artillery, and first-generation Murasame-class (31DDA) with slightly reduced ASW strengthened artillery was adopted.

But for the Second Defense Program it was decided to introduce a framework for a maritime defense force appropriate for Japan, which at the time was split between an escort fleet with three escort groups: Two main groups plus one backup of older ships. The Third Escort Group had notably the Kusu-class (Matsu/Tachibana), hastily constructed wartime destroyer, while securing new destroyers within the limited budget left few options. The Second Defense Program repeated the high-low mix with versatile, high-performance destroyers (DDAs) and cheaper, mass-produced escorts (DDKs) for the numbers. The “high” were the Takatsuki-class (38DDAs), and the DDKs became the Takatsuki-class.

There was a delay in whuch the Takatsuki-class planning had to integrate an U.S. deployment surveys and other factors, while the Second Defense Program was discussed. Three were planned FY1962 to 1964. This after the 1965 plan were designated as “Minegumo-class” but redesigned to replace the ASROC with the QH-50 DASH promoted by the USN. However in 1969, the US Navy itself decided to pull the plug of the ASW drone and three more vessels of the 1971 plan were reverted to ASROC. Those for the 1974 plan, 4th Defense Program were planned as 2,500-ton destroyers with CODOG but the oil crisis cancelled these and reverted to the Yamagumo design.

Design

Hull and general arrangements

The design was based in many respects on the Dekitakami-class (36DE), basic design number E104. The hull used a wave-proof deck design with two full-length decks and yet a flush-deck appoach. The three amidship compartments (bulkheaded) were occupied by engine rooms, with two separate intake and exhaust ducts, one fore and one aft. The first batch displaced 2,050 long tons (2,083 t) standard, for 114.0 m (374 ft 0 in) long overall, a beam of 11.8 m (38 ft 9 in) and draft of 3.9 m (12 ft 10 in).

The bridge structure was 2.5 storey tall for the forward section only and like for the Isuzu-class, comprised an enclosed bridge with wings on both sides. The first funnel exhausted port-side engine, was adjacent to the bridge and behind was the aft superstructure including the second Mk. 63 system, ASROC and amunitions store, integrated with the second funnel. This design on trials however showed issues of viabrations from the diesels onto various electronic equipment. In later designs, the sensors were separated by one meter and placed as a separate structure. For their crew of 210-220 they carried a motorboat and one cutter.

With their class, and late model (40DDA) as well as the Minegumo sub-class, they had knuckle lines at the bow to improve seakeeping, plus an overhang at the stern, and an air defense command post above the bridge, with a lattice-structured aft mast. Hull dimensions were slightly enlarged on that latter batch. The poop was mosified also to receive the VDS and for this, an overhang was given at the stern. Also this later batch measured 115.2 m (377 ft 11 in) overall for the same beam, and greater draft at 4.0 m (13 ft 1 in).

Powerplant

The 36DE type uses the same CODAD (Diesel and Diesel) featuring multiple-diesel main engine configuration on their two shafts and officially both early and late batches had the same output of 26,000 hp. The early batch had four Mitsui 1228 V3 BU-38V diesels and two Mitsui 1628 V3 BU-38V diesels. But the latter batch had a more uniform six Mitsubishi 12 UEV 30/40 diesels. These were all high-output, two-stroke, V-type medium-speed diesel engines.

In 1966, the class attracted attention as the world’s fastest (27-28 knots) and most powerful CODAD surface combatants. While this allowed for a long cruising range despite the small size of this powerplant and limited fuel capacity, the output did not reach 30,000 horsepower, forcing a compromise on 27 knots, slower than the 30 knots of the 31DDA, let alone the 32 knots the JMSDF had targeted. The engines were procured either by Mitsubishi or Mitsui as seen above.

The Mitsubishi engines were same 12UEV30/40 as the Kitakami, but with increased power output of 4,650 horsepower. In contrast, the Mitsui diesels repeated Ooi’s engines, the 1228V3BU-38V rated at 4,250 horsepower, plus two 1628V3BU-38V engines, upgraded to 16 cylinders, increased to 5,600 horsepower. In both cases, these diesels were arranged in a shift configuration, but unlike the Kitakami-class, the port-side shaft was located forward and the starboard shaft aft as on turbine destroyers.

Both batch had three engine rooms, forward, middle, and aft. Two in each, with the forward engine room and port-side engine in the middle engine room driving the port-side shaft, the starboard-side engine in the middle engine room and two engines in the aft engine room driving the starboard shaft. Time was required to increase the number of main engines to use combat speed and it caused significant vibration and noise, not a good thing when trying to hunt down a submarine.

These had a negative impact on the maintenance of electronics, while the high noise level crippled efficience of the sonar receiver and negated the detection range, a major problem for this class, in addition to the lack of ASW helicopter. In addition these ships came equipped with diesel generators, two 400-kilowatt, one 200-kilowatt emergency generator,and for the second batch, a single main generator rated for 500 kilowatts.

Armament

It was a repeat of the Ayanami-class (30DDK) and Kitakami-class (36DE) but updated and considered the first to meet international standards.

Main Guns

From the start it was self-defensive only, but four instead of just two 3-in/50 (76mm) twin rapid-fire guns made in Japan as the Type 57, equivalent of the Mk.33 3″/50 plus the two associated gun fire control systems on the bridge’s roof. Albeit these main gun was the same twin 50-cal. 76mm rapid-fire model of the Ayanami-class, the early batch retaine the conventional Type 57, and the latter batch had the standardized Type 68.

The associated main gun fire control system was the latest American Mk.56, a high-performance model with a X-band Mk.35 radar, capable of automatic tracking, blind firing. The Harukaze-class (28DD) requested this early but this was rejected by the USN. The secondary GFCS aft was the same Mk.63 as the Ayanami-class with a Japanese windscreen. However the use of ASROC led to use the Mk.56 for missile tracking, and anti-aircraft fire was solely handled by the manual Mk.63, resulting in a reduced ability to counter airborne threats when performing an ASW attack. In later batches this was resolved by standardizing both the main and secondary GFCSs using the Japanese Type 72 Fire Control System Type 1B (FCS-1B), capable of autotracking and blind firing.

RUR-5 ASROC

In addition, the longer-range ASROC with their 8-barreled launchers were installed for the first on a Japanese DD, on the center deck, with the spare magazine installed on the aft superstructure. This location was criticized for significantly restricting the firing range forward and aft however, but not conttadicted naval commanders’s preferred circular method of attack, in which multiple ships surrounded the submarine, maintained sonar detection while attacking, used at the time. For specs, see navweaps

Type 71 375mm ASWRL

For closer range ASW attacks, tghese destroyers were the first to come with the Type 71 Bofors rocket launcher, a licensed version of the M/50 375mm anti-submarine rocket launcher already used on the Kitakami-class, and 324mm introduced on the later-built Umitaka-class and Mizutori-class submarine chasers (36PC). This was associated with the Underwater Strike Control System (SFCS), the American-made Mk.114 for ASROC and Japanese SFCS-1C-3 for the Bofors, on the latter batch both integrated into the SFCS-2.

HOS-301 324mm TTs

A Japanese copy of the US standardized triple 324 mm torpedo tibes for the Mark 46 acoustic ASW torpedo, built in Japan, both the tubes and torproedoes as the HOS-301.

Electronics

The Combat Information Center (CIC) was located within the forward superstructure, adjacent to the rear of the bridge. The proximity of the tactical center and the navigation center greatly improved operability. The latter batch added to this an air defense command center above the bridge as well. These were the first destroyers equipped with the Japanese OPS-11 air search and warning radar, based on the American-made AN/SPS-40 with a distinctive Yagi dipole array antenna.

The early batch had the US AN/SQS-23 sonar, fixed hull bow (chin) radar, making them the first Japanese destroyers to feature such as bulbous bow sonar. The bow dome was modeled after US Navy ressearches, a thin-plate structure with trussed vertical and horizontal framework, made of thin, high-tensile steel to withstand anchor chain contact, reducing any sound wave transmission loss. The later batch had the Japanese OQS-3 offering equivalent performance. Akigumo and Yuugumo had also the SQS-35(J) variable depth sonar (IVDS), another first at commission, retrofitted on Yamagumo and Makigumo. However it was criticized for its low operational efficiency and unstable positioning, low accuracy and declared not satisfactory.

For active eletronic protection, the first batch had the NOLR-1B, an improved version of the Ayanami-class own ESM, and the latter batch had the NOLR-5, positioned more than twice as high to improve detection performance. The Aokumo sub-class was later upgraded with NOLR-6B in 1979.

Modernizations

1991, Yamagumo, Makigumo: received a lecture room under the ASROC launcher and a chart room added on the signal deck.

Conway’s rendition of the Yamagumo class

⚙ specs. Yamagumo as completed
Displacement	2,050 long tons (2,083 t) standard
Dimensions	114 x 11.8 x 3.9 m (374 ft x 38 ft 9 in x 12 ft 10 in)
Propulsion	2 shafts 4× Mitsui 1228 V3 BU-38V, 2× Mitsui 1628 V3 BU-38V diesels 26,000 bhp*
Speed	27 kts (31 mph; 50 km/h)**
Range	6,000 nmi (11,000 km)
Armament	4× Mk.33 3″/50, ASROC, 1×4 Bofors 375 mm ASWRL, 2×3 HOS-301 324 mm TTs
Active Protection	NOLR-1B
Sensors	AN/SQS-23, Mark 56 FCs, Mark 63 FCs
Crew	210

*Makigumo and Akigumo 6 × Mitsubishi 12 UEV 30/40

**Yūgumo 28 knots (32 mph; 52 km/h)
***NOLR-6 for Akigumo and Yūgumo

⚙ specs. Aokumo as completed
Displacement	2,150 long tons (2,185 t) standard*
Dimensions
Propulsion	6× Mitsubishi 12 UEV 30/40N diesels
Speed	Same
Range	Same
Armament	Same
Active Protection	NOLR-1B
Sensors	OQS-3 (Type 66 passive sonar), VDS AN/SQS-35(J), OPS-11B, OPS-17
Crew	220

*Yūgumo 2,200 long tons (2,235 t) standard

The Yamagumo class in service

Yamagumo DD113

やまぐも Yamagumo was laid down at Mitsui, Tamano on 23.3.1964, launched at the same Mitsui Engineering & Shipbuilding Tamano Shipyard on 27 February 1965 and commissioned on 29 January 1966. On 19 March 1966, she joined the newl created 21st Escort Corps, 2nd Escort Corps group, with JDS Makigumo, commissioned on the same day. She took part in three long range Paicific trainng cruises in 1971, 1975 and 1981.
On 1 December 1977, the 21st Escort Corps ended under the the 3rd Escort Corps group and on 20 February 1987, it was reorganized under the Sasebo District Force.

On 20 June 1991, she was reclassified as a training vessel redesignated TV-3506. She was transferred to the 1st Training Squadron and her home port transferred to Kure. She was rebuilt as a training ship from 28 June to 24 October, with the ASROC launcher now used as a trainee auditorium with 36 cadets, and part of the officer’s bedroom was reconverted as a female officer room (14). She was decommissioned and stricken from the register on 1 August 1995.

JDS Makigumo DD114

まきぐも Makigumo was laid down at the Uraga Dock Company Uraga Shipyard on 10 June 1964, launched on 26 July 1967 and commissioned on 19 March 1966. On 1 December 1977, her unit, the 21st Escort Corps, was reorganized under the 3rd Escort Corps group. In 1985, she took part in an oceanic long range training cruise. On 20 February 1987, her unit was reorganized under the Sasebo District Force. On 20 June 1991, she was reclassified as training vessel registration changed to TV-3507. She was transferred to the 1st Training Squadron, Kure. She was converted as such between 28 June to 24 October, with the ASROC launcher redone as a trainee auditorium and a new female officer’s bedroom for 14. She was stricken on 1 August 1995.

JDS Asagumo DD115

あさぐも Asagumo was laid down at Maizuru Jukogyo, Maizuru on 24.6.1965 (Hitachi Zosen Corporation) and launched on 25 November 1966, commissioned on 29 August 1967. On 25 November 1972, she was under the 23rd Escort Corps under the 2nd Escort Corps group, joining JDS Aokumo. On 27 March 1982, she was transferred to the 21st Escort Corps, 3rd Escort Corps and took part in a long training cruise. On 20 February 1987, her unit fell under the Sasebo District Force. On 15 March 1991, she was transferred to the 22nd Kure District Force Escort Corps, home ported to Kure. On 18 October 1993, she was reclassified as a “special service ship” registration changed to ASU-7018. Next she was transferred to the 1st Submarine Group under direct control. She was also reconverted as special service ship with a new facility for training torpedoes port side amidship. She was discarded and stricken from the register on 24 March 1998.

Aokumo DD119

あおくも Aokumo was laid down at Sumitomo Heavy Industries (Uraga Shipyard) on 2 October 1970, launched on 20 March 1972 and commissioned on 25 November 1972. She joined the 23rd Escort Corps along with JDS Asagumo, at Sasebo. She took part n long overseas training cruises in 1974 and 1978. From July 17 to August 28, 1976, she was present for RIMPAC 1976 with JDS Akigumo, Narushio and eight P-2J aircraft.
On October 5, 1979, at the Terashima harbor, Nagasaki Prefecture, she collided in a night anchoring training under the moonlight and without radar or lighting, the starboard side of JDS Akigumo. The latter was holed at the waterline, a crack on her starboard bow waterline but the damage was still limited overall.

On March 27, 1982, the 23rd Escort Corps was reorganized under the 4th Escort Corps group, Ominato. On January 31, 1990, the 23rd Escort Corps was reorganized under the direct control of the Ominato District Force. Her crew took part in the relief after the disaster of the Hokkaido Nansei-oki Earthquake on July 2, 1993. On March 24, 1997, the 23rd escort corps became the 25th escort corps. On March 18, 1999, she was reclassified as training vessel, registered TV-3512. She was transferred to the 1st Training Squadron, home ported to Kure.
She was removed from service on June 13, 2003. While in commission she crossed 820,117 nautical miles, 41 times a globe tour.

Akigumo DD120

あきぐも Akigumo was laid down at Sumitomo Heavy Industries, Uraga Shipyard, on 7 July 1972. She was launched on 23 October 1973 and commissioned on 24 July 1974. From 17 July to 28 August 1976, she took part in RIMPAC 1976 with JDS Aokumo, Narushio and eight P-2J aircraft. Dueing a mooring training without radar or light (under the moonlight) on 5 October 1979 at Terashima harbor, Nagasaki Prefecture, JDS Aokumo rammed her aft starboard hull. It was breached at the waterline with, Aokumo having a small crack at her starboard bow waterline. Repairs were swift, no casualties.

In 1980, Akigumo took part in the JMSDF’s 24th Ocean Training Cruise. On 27 March 1982, the 23rd Escort Corps unded under the 4th Escort Corps Group, homeported to Ōminato. On 31 January 1990, the 23rd Escort Corps fell under direct control of the Ōminato District Force. On 24 March 1997, it was renamed the 25th Escort Corps due to the post- cold war budget reduction and fusion or deletion of several units.
Akigumo took part in disaster relief operations after the eruption of Mount Usu that on 31 March 2000. On 13 June, she was converted to a training ship, redesignated TV-3514. She was transferred to the 1st Training Squadron, Kure. She was decommissioned on 16 February 2005. In her service she crossed 600,000 nautical miles, 29 globe tours.

Yugumo DD121

ゆうぐも Yugumo was laid down at Sumitomo Heavy Industries on 4 February 1976, launched on 21 May 1977, commissioned on 24 March 1978. On March 27, 1982, she was transferred to the 23rd Escort Corps, 4th Escort Corps, home ported to Ominato. On January 31, 1990, the 23rd Escort Corps fell under direct control of the Ominato District Force. Soo took part in disaster refief operations after the Hokkaido Nansei-oki Earthquake of July 12, 1993. On March 24, 1997, the 23rd escort corps became the 25th escort corps. She als took part in disaster relief after the eruption of Mount Usu on March 31, 2000. She was decommissioned on June 17, 2005, spanning 652,372 nautical miles in commission, 30 earth circles.