IJN I-171

KD 6AType

As seen in 1942

Hasegawa no. 433

Scale 1:700 Water Line Series

Click on the pictures to enlarge.



2 3 4


6 7 8



10 11  

KD6A/B Types

Longer and fitted with more powerful diesels, these boats could achieve 23 knots (42.6km/h) surfaced, the highest surface speed of any submarine in the mid-1930s. The KD6B variant was slightly longer and weighed some 25 extra tons, which provided an increased diving depth to 278ft (84.8m). All eight boats were completed between 1934 and 1938. In 1942-43, 1-172 and apparently 1-171 and 1-174 were converted into cargo carriers by removing the deck gun and a number of torpedo reloads. At least 1-172 could carry a 46ft (14m) daihatsu landing craft in addition to internal and deck cargo.

Armament: Six 21-in. bow torpedo tubes and 14 torpedoes. The first three boats carried the 3-in. gun; the last five mounted a 4.7-in. deck gun. All boats were also equipped with a 13mm machine gun (except 1-174 and 1-175, which mounted two).

War service: This class scored some major successes, but the loss of all eight boats showed the futility of using large submarines to attack heavily defended US fleet targets. All eight units were deployed to support the Pearl Harbor operation, where 1-70 became the first Japanese submarine lost during the war, on December 10, when she was bombed by carrier aircraft. The class was also active during the Midway operation, when 1-168 scored the biggest Japanese submarine success of the war when she torpedoed and sank the already damaged fleet carrier USS Yorktown and a destroyer off Midway on June 6. Later, the KD6 boats participated in the evacuation of Kiska and supply missions in the Solomons. 1-175 scored the other major KD6 success when she responded to the US invasion of the Gilbert Islands in November 1943 and sank the escort carrier USS Liscome Bay. Other ships sunk by this class included a fleet oilier and five merchants. 1-172 and 1-173 were 1942 losses to unknown causes and a US submarine, respectively.

1-168 was lost to US submarine attack in 1943. The final four boats were lost in 1944, two to surface forces and one to air attack, while 1-169 was lost in a diving accident at Truk.

Technical specifications

Units in class: 17

Displacement: 1,785 tons surfaced; 2,440 tons submerged

Length 104.7m

Beam 8.02m

Draft 4.6m

Two diesels with 9,000shp driving two shafts; electric motors With 1,800shp

Speed 23kt surfaced; 8.25kt submerged

Range: 25.928km at 16kt. surfaced

Operating depth: 74m

Crew: 70


Building the model

This was a very straightforward building process with only small modifications, such as PE-set railing (3bars) from Lion Roar, and some PE ladders etc. The RDF-antenna, flagstaff, mast and periscopes where made of silver and copper wire. The only major work was the "hollowing up" of the command tower (just as I made the stacks on other models. After a new deck was added inside the tower, I used the range finder from Pit Road surplus spurs. All in all a fine little building process, with no surprises along the way. The crew is from Eduard IJN 1/700 PE-set.


Books form my own library :  

Japanese Naval Warship Photo Album Submarines and depot ships

from Diamond Sha books.  


Submarines of the Imperial Japanese Navy 1904-1945 from Conway Maritime press

(Pictures and history)


Imperial Japanese Navy  Submarines 1941-45 from Osprey publishing

(Pictures and history)

The building time was 2 days. 

Jan. 2010

If you have any questions, remarks or things you will share, please don't hesitate to contact me.



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