IJN Ikoma (BC-1907 (ADV-1927-mod))


Return to Japanese Navy page:


First of the new heavily armed and faster armoured cruisers that Japan had designed and built post-war. The Tsushima Battle had shown the advantages that having fast and large scouting ships. Rated as armoured cruisers through to 1912 when the new rating 'Battlecruiser' was brought in by the Royal Navy.

The Ikoma was almost 20 years old when it was taken in hand for full refurbishment to the Area Defense Vessel type. Because of its age the Ikoma did not have as many new features fitted as some of the more modern pre-dreadnoughts. A cruiser style bridge superstructure was fitted, the funnels were trunked together to clear space for the new superstructures. The lower gun deck was removed completely and plated over. The upper gun deck was revamped to fit six of the single 5.5" guns as fitted to the light cruisers of the time. One twin 5.5" which was the trial unit for the last of the light cruisers which were to go from seven single guns to four twins (a hint for what is to come). The 5.5" being low angle guns, four 3" AA weapons were fitted for anti-aircraft use, while some of the first twin 25mm mountings were fitted before 1930. The original seven inch side armour was replaced with a thinner 2" belt over the vitals, mainly for defense from light weapons.

The Ikoma had a very busy start to the war. Taking part in the subjugation of the Dutch East Indies, the Ikoma's main duties were to drop off troops to all of the smaller islands that had populations. Any resistance was answered by the guns of the Ikoma. On to 1942 and the Ikoma has the duty of flying patrols around the Solomon Islands, based on Guadalcanal, while an airfield was being built. The Ikoma resisted the US Marines landing and taking of the airfield. Its guns cratering the airfield to deny its use to US aircraft while giving Japanese forces a chance to retake the airfield. SBD Dauntless dive bombers from Admiral Halsey's carriers cured the problem of the Ikoma, hitting the old ship with half a dozen or more 500lb bombs which blew out the bottom of the ship. The crew tried to beach the ship, so it would become a static gun emplacement, but failed and the ship capsized in deeper water, becoming a complete loss.


Displacement 13,800 tons std, 16,250 tons full load
Length 471 ft
Breadth 75 ft
Draught 26 ft
Machinery 2 shaft Steam turbines, 22,000shp
Speed 21 knots
Range 3,500 miles at 18 knots
Armour 2" side, 2" deck, 7" turrets.
Armament 2 x 12" (1x2)

8 x 5.5" (1x2, 6x1)

4 x 3" AA (4x1)

8 x 25mm (4x2)

Aircraft 3-6
Torpedoes nil
Complement 840
Notes IJN Tsukuba (1905-1907) Sunk 01/1917 by magazine explosion.

IJN Ikoma (1905-1908) Sunk 1942 off Guadalcanal.

Above - old drawing for ADV conversion.

Ikoma as completed 1908 and as the ship was used during WW1. Ikoma and Tsukubas first WW1 duty was to chase after Von Spee's Squadron of cruisers in conjunction with the two Kurama class battlecruisers. Just those four ships would have seriously outgunned Von Spees ships.


Return to Japanese Navy page: