IJN Torpedo Cruisers: Kitakami & Oi

In a previous post, we examined the Type 93 torpedo and briefly discussed the role that it was expected to play in the decisive battle. In this post, we will look at the modified Kuma-class cruisers Kitakami and Oi, which were envisioned to play a role in the torpedo attacks during the decisive battle as a part of a Night Battle Force.

• Builder: Sasebo Navy Yard (Kitakami), Kawasaki Heavy Industries in Kobe (Oi)
• Laid down: 1 September 1919 (Kitakami), 24 November 1919 (Oi)
• Launched: 3 July 1920 (Kitakami), 15 July 1920 (Oi)
• Completed: 15 April 1921 (Kitakami), 3 October 1921 (Oi)
• Fate: Scrapped on 10 August 1946 (Kitakami), torpedoed by the submarine USS Flasher on 10 September 1944 (Oi)

Characteristics

• Displacement: 5,100 tons (standard)
• Dimensions: Length 532 feet, beam 46.5 feet, draft 29 feet
• Speed: 36 knots
• Propulsion: 4x Gihon geared turbines (4 shafts), 12 Kampon boilers, 90,000 shp
• Range: 9,000 nm at 10 knots
• Protection: Main belt 2.5 inches, deck 1.1 inches
• Crew: 37 officers, 413 enlisted (plus space for a staff of 5 officers and 22 enlisted)

Armament (as built)

• 7x 5.5”/50 guns
• 2x 3.15”/40 AA guns
• 4x dual 21” torpedo tubes

Armament (after conversion to torpedo cruiser)

• 4x 5.5”/50 guns
• 10x quadruple Type 92 24” torpedo mounts
• 2x twin 25mm guns

Armament (after kitakami’s conversion to kaiten carrier)

• 2x Type 89 twin 5”/40 AA guns
• 12x triple & 31x single 25mm guns
• 2x Type 13 radar sets
• 1x Type 22 radar set

Design

On 25 August 1941, the Kitakami and Oi were ordered to Sasebo for conversion to “torpedo cruisers.”  Originally, the Kiso was to be converted as well, but by 1938 there were not enough Type 92 quadruple torpedo mounts, so the Kiso was dropped from the conversion plans.  

For the conversion, the four forward 5.5” guns were retained and the aft three were removed.  The dual 24” torpedo mounts were replaced with ten quadruple torpedo mounts, five on each side, for a total of 40 torpedoes.  Although no reloads were carried, a system of rails was installed to allow for torpedoes to be transferred between the mounts.  Two twin 25mm guns were mounted abreast of the first smokestack. The torpedo fire control station on the foremast was modified to allow for ranges greater than 32,700 yards and a 20-foot rangefinder was installed above the compass bridge (Stille, 2013, p. 202).  To accommodate the quadruple torpedo mounts, sponsons were added to the sides of the ships (Watts & Gordon, 1971, p. 130). Watts and Gordon (1971) note different AA gun configurations for these ships with Kitakami eventually carrying six triple and 18 single 25mm guns and the Oi mounting two triples, six doubles, and four single 25mm guns (p. 130).  As a result of these modifications, the standard displacement increased to 5,860 tons and the speed dropped to 31.67 knots as was seen during a speed trial on the Kitakami in December 1941 (Stille, 2013, p. 203). The conversions of the Kitakami and Oi are completed on 30 September 1941 (Hackett & Kingsepp, 2018).

Operational History

As newly converted torpedo cruisers Kitakami and Oi spent the first several months of 1942 in Japanese home waters conducting training.  On 11 May, the Kitakami and Oi were assigned to Cruiser Division 9 and attached to guard the Main Body of the Aleutians Screening Force under Admiral Takasu Shiro.  The Aleutian Screening Force consisted of Battleship Division 2 (Ise, Hyuga, Fuso, & Yamashiro) and its escorts of Destroyer Division 20 (Amagiri, Asagiri, Yugiri & Shirakumo), Destroyer Division 24 (Kawakaze, Yamakaze, Suzukaze & Umikaze), Destroyer Division 27 (Ariake, Yugure, Shigure & Shiratsuyu), and the 2nd Supply Unit’s oilers (San Clemente & Toa Maru) (Hackett & Kingsepp, 2018).  The Aleutian Screen Force sortied on 29 May 1942. However, they would see no combat during the Battle of Midway.

In August of 1942, both Kitakami and Oi were again modified to act as fast transports. The four after-torpedo mounts were removed and 46-foot “Daihatsu” landing barges were attached. Additionally, two triple 25mm guns were fitted aft and depth charge rails were installed.  These modifications were completed in September (Hackett & Kingsepp, 2018).

Kitakami and Oi would spend most of their careers as fast transports running around Truk, Indonesia, and Singapore. The rest of the careers of these ships are not the focus of this post, however, after Kitakami was damaged by torpedoes from the submarine HMS Templar in January 1944, she was converted to a Kaiten manned-torpedo carrier later that year in August (Hackett & Kinsepp, 2018).  As the name would imply, a Kaiten was a Type 93 torpedo that had been modified to act as a man-guided suicide weapon. For her conversion to a Kaiten carrier, Kitakami’s armament was stripped and replaced with two Type 89 127mm AA guns fore and aft, as well as 12 triple and 31 single 25mm guns.  Two depth charge rails and two depth charge throwers were also fitted. Her main weapons were now 8x Model 1 Kaiten manned torpedoes which were launched from two sets of rails on each side of the rebuilt aft end of the ship with one Kaiten capable of being launched every 8 minutes. Her torpedo directors were removed and replaced by additional AA fire control equipment.  Two Type 13 and one Type 22 radar sets were fitted. Crew size rose to 615 (Stille, 2013, p. 204). A 20-ton crane from the Chitose was also fitted to the mainmast. Kitakami’s damaged engine room also necessitated a rebuild. A turbine was removed and the after-engine room was repurposed to store batteries and generators. Subsequently, her horsepower dropped from 90,000 to 30,000 giving her a speed of 23 knots (Watts & Gordon, 1971, p. 131).  Kitakami would survive the war and be scrapped in 1947. Oi was not so lucky, as she was sunk on 19 July 1944 during a dramatic battle with the submarine USS Flasher in the South China Sea.

Evaluation

Given their larger displacement and higher freeboard, the Kuma-class, in general, were known to be very seaworthy (Stille, 2013, p. 199).  However, as with many Japanese naval vessels, the Kitakami and Oi are examples of missed opportunities and perhaps dogmatic thinking. Since the only major operation that these ships participated in as torpedo cruisers were the Battle of Midway where they were hundreds of miles away from anything remotely resembling combat, we can only conjecture as to what they could have done.  It has been noted that the Aleutian Screening Force was not actually a formal part of the forces outlined for the Aleutians operation and was only mentioned in passing in planning documents (Parshall & Tully, 2005, p. 46). In the opinion of historians Jonathan Parshall and Anthony Tully (2005), with a top speed of 24 knots, the Aleutian Screening Force would not have been a credible threat had the American carrier force encountered it since it did not have the speed to run away.  Furthermore, it was equidistant between two friendly forces meaning that it was in no position to quickly support either the Main Body under Admiral Yamamoto in the south or the Aleutians forces in the north (p. 54 – 55). Parshall and Tully (2005) also opine that:

If the premise is accepted that the Americans would have to be lured from Pearl Harbor in order to create the needed battle, there was no way to construct an operational plan whose distribution of warships was both deceptive and mutually supporting.  The two goals were antithetical. Yamamoto knew he couldn’t have it both ways, and he willingly sacrificed mutual support to the perceived need for stealth. In a very real sense, this one assumption about the nature of the enemy doomed the battle plan from the start. (p. 55)    

Basically, Parshall and Tully argue that Admiral Yamamoto created a needlessly complex operational plan that spread the Japanese forces too thin, and tried to accommodate too many variables, while at the same time, failing to factor in unknown variables with the expectation that the Americans would behave in a very specific manner.  Their conclusion that the Aleutian Screening Force presented no credible threat appears to be predicated on the idea that the American carrier planes would have spotted them and attacked before the escorting cruisers and destroyers got into range of the American carriers to use their Type 93 torpedoes. The Screening Force was too slow to outrun them and too far away to receive any support from friendly Japanese units.  While we cannot be certain that this is what would have happened (counterfactual history is a dangerous minefield), Parshall and Tully’s conclusion seems sound. If we factor in Joseph Czarnecki’s opinion that the speed of the Type 93 was its most tactically useful aspect, then we can likely conclude that the Kitakami and Oi, as torpedo cruisers, would have been very dangerous in the fighting in the Solomons had they not been converted to act as fast transports and instead been leading destroyer squadrons. Alas, they spent less than a year in their configuration as torpedo cruisers.

References

Hackett, B. & Kinsepp, S. (2018). IJN Kitakami: Tabular Record of Movement. Retrieved from http://www.combinedfleet.com/kitakami_t.htm

Jentschura, H., Jung, D., & Mickel, P. (1982). Warships of the Imperial Japanese Navy, 1869-1945 (A. Preston & J.D. Brown, Trans.). Annapolis, MD: Naval Institute Press. (Original work published 1970)

Parshall, J.P. & Tully, A.P. (2005). Shattered Sword: The Untold Story of the Battle of Midway. Dulles, VA: Potomac Books.

Stille, M.E. (2013). The Imperial Japanese Navy in the Pacific War. Oxford, UK: Osprey Publishing.

Watts, A.J. & Gordon, B.G. (1971). The Imperial Japanese Navy. Garden City, NY: Doubleday & Company Inc.