Ro-sixty six was an Imperial Japanese Navy Kind L submarine of the L4 subclass. First commissioned in 1927, she served in the waters of Japan previous to World Warfare II. During World War II, she operated within the Central Pacific and supported Japanese forces in the Battle of Wake Island until she sank after a collision in December 1941.

Design and description
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The submarines of the type L4 sub-class have been copies of the Group 3 subclass of the British L-class submarine built under license in Japan. [1] They had been slightly larger and had two more torpedo tubes than the preceding submarines of the L3 subclass. The submarines had been 78.39 meters (257 ft 2 in) long and had a beam of 7.Forty one meters (24 ft four in) and a draft of 3.96 meters (13 ft zero in). They’d a diving depth of 60 meters (197 ft). [1] They displaced 1,004 tonnes (988 long tons) surfaced and 1,322 tonnes (1,301 long tons) submerged.

For floor running, the submarines have been powered by two 1,200-brake-horsepower (895 kW) Vickers diesel engines, each driving one propeller shaft. On the surface, they’d a range of 5,500 nautical miles (10,200 km; 6,300 mi) at 10 knots (19 km/h; 12 mph); submerged, they’d a variety of 80 nmi (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph). They might reach 15.7 knots (29.1 km/h; 18.1 mph) on the surface and 8.6 knots (15.9 km/h; 9.9 mph) underwater. When submerged, every propeller was driven by an 800-shaft-horsepower (597 kW) electric motor.

The submarines have been armed with six internal 533 mm (21 in) torpedo tubes, all within the bow, and carried a total of twelve 6th Yr Kind torpedoes. They were also armed with a single 76.2 mm (three in) deck gun and a 6.5 mm machine gun.

Building and commissioning
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Ro-sixty six was laid down on 1 December 1925 by Mitsubishi at Kobe, Japan.[2][3] Launched on 25 October 1926,[2][3] she was accomplished and commissioned on 28 July 1927.[2][3]

Service historical past
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Pre-World Struggle II
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Upon commissioning, Ro-sixty six was connected to the Sasebo Naval District and assigned to Submarine Division 27 – through which she spent her complete career – in Submarine Squadron 1 in the first Fleet within the Combined Fleet.[2][3] Submarine Division 27 was reassigned to the Sasebo Defense Division within the Sasebo Naval District on 30 November 1929.[2] On 24 December 1929, the division was reassigned to Submarine Squadron 2 within the 2nd Fleet in the Mixed Fleet.[2] Ro-66 was decommissioned and positioned in reserve at Sasebo, Japan, on 15 November 1930.[2][3]

Ro-sixty six was recommissioned on 1 Could 1931,[2] resuming active service in Submarine Division 27, which by then had been reassigned to the Sasebo Protection Division within the Sasebo Naval District. Ro-66 once more was decommissioned. [2][3] Placed in reserve at Sasebo. [2] On 1 October 1932, the division was reassigned to the Sasebo Guard Squadron.

Ro-66 was recommissioned on 15 November 1934,[2] and returned to service in Submarine Division 27 which by then again was serving within the Sasebo Guard Squadron within the Sasebo Naval District.[2] The division was transferred to the Sasebo Defense Squadron on 15 November 1935.[2]

Sources supply different accounts of Ro-66′s standing throughout 1938-1940, implying each that she was in full fee all through these years[3] and stating that she was out of fee and in reserve – in Second Reserve from 15 December 1938 to 15 November 1939 and then in First Reserve until 15 November 1940[2] – within the Sasebo Naval District between December 1938 and November 1940.[2] Regardless of the case, she was again in lively service in time for Submarine Division 27′s reassignment to Submarine Squadron 7 in the 4th Fleet in the Mixed Fleet on 15 November 1940.[2]

When the Imperial Japanese Navy deployed for the upcoming conflict within the Pacific, Ro-sixty six was at Kwajalein in the Marshall Islands with the opposite submarines of Submarine Division 27, Ro-sixty five and Ro-67.[3] She acquired the message “Climb Mount Niitaka 1208” (Japanese: Niitakayama nobore 1208) from the Mixed Fleet on 2 December 1941, indicating that warfare with the Allies would begin on 8 December 1941 Japan time,[3] which was on 7 December 1941 on the opposite facet of the Worldwide Date Line in Hawaii, the place Japanese plans called for the warfare to open with their attack on Pearl Harbor.

World War II
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Battle of Wake Island
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On 6 December 1941, Ro-66 received underway from Kwajalein with the commander of Submarine Squadron 27 embarked to conduct a reconnaissance of Wake Island,[3] which the Japanese deliberate to invade on eight December 1941, the first day of the battle on Wake Island′s facet of the International Date Line. [3] The Battle of Wake Island began on 8 December 1941, with Ro-65, Ro-66, and Ro-67 patrolling in the area supporting Japanese forces attempting to grab the atoll. [3] United States Marine Corps forces defending Wake drove back the preliminary Japanese assault that day.

While the Japanese gathered reinforcements for a second and larger invasion of the island, Submarine Squadron 7 despatched orders to all three submarines of Submarine Division 27 on 12 December 1941 directing them to return to Kwajalein. [3] Consequently, she continued to patrol off Wake Island[3] because the submarines of Submarine Division 26 – Ro-60, Ro-61, and Ro-62 – arrived in the realm to relieve the departing submarines. [4][5][6] [3] Accordingly, Ro-sixty five and Ro-67 headed back to Kwajalein, but a radio failure prevented Ro-sixty six from receiving the orders despite three makes an attempt by Submarine Squadron 7 to contact her.

Loss
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Ro-66 was on the surface 25 nautical miles (46 km; 29 mi) southwest of Wake Island – bearing 252 levels from the atoll – to recharge her batteries in a heavy squall in the predawn darkness of 17 December 1941 when her lookouts all of a sudden sighted Ro-62, additionally on the surface and recharging batteries. [3][6] Ro-sixty six sank at 19°10′N 166°28′E / 19.167°N 166.467°E / 19.167; 166.467 (Ro-66)[2] with the loss of 63 lives, including that of the commander of Submarine Division 27.[2][3][6] Ro-62 rescued her three survivors, who had been thrown overboard from her bridge by the collision. [2][3][6] Both submarines attempted to back off, but it was too late to avoid a collision, and Ro-sixty two rammed Ro-66 at 20:20 Japan Commonplace Time. [2][3][6]

The Battle of Wake Island concluded on 23 December 1941 with the Japanese conquest of the atoll.[3] The Japanese struck Ro-66 from the Navy record on 15 January 1942.[3]

^ a b Chesneau, Roger, ed., Conway′s All the World′s Preventing Ships 1922-1946, New York: Mayflower Books, 1980, ISBN 0-8317-0303-2, p. 203.

^ a b c d e f g h i j ok l m n o p q r s t u v “RO-66”. iijnsubsite.info. 2016. Archived from the unique on March 1, 2017. Retrieved 21 October 2020.

^ a b c d e f g h i j ok l m n o p q r s t u Hackett, Bob; Kingsepp, Sander (2017). “Sensuikan: IJN Submarine RO-66: Tabular Document of Motion”. combinedfleet.com. Retrieved 21 October 2020.

^ Hackett, Bob; Kingsepp, Sander (2017). “Sensuikan: IJN Submarine RO-60: Tabular Report of Movement”. combinedfleet.com. Retrieved 17 October 2020.

^ Hackett, Bob; Kingsepp, Sander (2017). “Sensuikan: IJN Submarine RO-61: Tabular File of Motion”. combinedfleet.com. Retrieved 17 October 2020.

^ a b c d e Hackett, Bob; Kingsepp, Sander (2017). “Sensuikan: IJN Submarine RO-62: Tabular Document of Motion”. combinedfleet.com. Retrieved 17 October 2020.

Bibliography
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“Rekishi Gunzō”., Historical past of Pacific Conflict Extra, “Excellent guide, The submarines of the Imperial Japanese Forces”, Gakken (Japan), March 2005, ISBN 4-05-603890-2

The Maru Particular, Japanese Naval Vessels No.Forty three Japanese Submarines III, Ushio Shobō (Japan), September 1980, Book code 68343-44

The Maru Particular, Japanese Naval Vessels No.132 Japanese Submarines I “Revised edition”, Ushio Shobō (Japan), February 1988, Guide code 68344-36

The Maru Special, Japanese Naval Vessels No.133 Japanese Submarines II “Revised edition”, Ushio Shobō (Japan), March 1988, E-book code 68344-37

Photograph of Ro-sixty six at combinedfleet.com

Type L submarine

Ro-51-class (Kind L1)

Ro-51

Ro-52

Ro-53-class (Sort L2)

Ro-fifty three

Ro-fifty four

Ro-fifty five

Ro-56

Ro-57-class (Sort L3)

Ro-57

Ro-fifty eight

Ro-fifty nine

Ro-60-class (Sort L4)

Ro-60

Ro-61

Ro-62

Ro-sixty three

Ro-sixty four

Ro-sixty five

Ro-66

Ro-67

Ro-sixty eight

Preceded by: Kind F submarine Followed by: Kaichū sort submarine

Retrieved from “https://en.wikipedia.org/w/index.php?title=Japanese_submarine_Ro-66&oldid=1335553109”

Ro-60-class submarines

Japanese L sort submarines

Ships constructed by Mitsubishi Heavy Industries

1926 ships

Maritime incidents in November 1942

Japanese submarine accidents

Submarines sunk in collisions

CS1: unfit URL

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This web page was last edited on 29 January 2026, at 21:22 (UTC).