IJN Tenryu (CL/A-1919)


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The Tenryu Class ships were Japans first try at an inline light cruiser, approximating the British Arethusa and early C class cruisers. Laid down in late 1916 they were not completed till early 1919. It was soon apparent that this size of cruiser had too many drawbacks and a new design was planned which became the Kuma class. The ships had been designed to act as Destroyer Leaders but at 34 knots it was felt they were not really fast enough to be the leaders to later Japanese destroyer classes like the Minekaze class which were making 39 knots.

The length to breadth ratio did not give a lot of leeway for the upgrading and replacing of older weapons and electronics. To add something to the ships required something else being removed.

The first proposed rebuilding to AA cruisers was mooted in 1936-37, as shown below. The rebuild was not proceeded with as the money was allocated to building new cruisers.

As can be seen the main portion of the AA armament is the twin 5" AA gun, otherwise it is much the same as the proposed rebuild below.

The real life proposed conversions above uses twin 76mm guns in open backed mountings. The torpedoes being removed, and the three funnels being trunked into one. The aft end looks like it is fitted for depth charges, so is probably earmarked for convoy escort duty. Troop convoy escort duty. In this guise the ships would only be useful as AA escort ships. Any destroyers and above that came against the ships would shoot them to bits. They would need escorts of their own against sea forces.

I must admit to quite liking how the drawing turned out. Moving the bridge and turret as far back as possible has allowed for some much needed buoyancy forward. The three twin 5" DP turrets will give a decent broadside and reinstating a bank of torpedoes (4x24") gives the ship some decent teeth to bite any bigger ship with. The ships still need to keep top weight down in case of stability problems.


Displacement 4,000 tons std, 4,800 tons full load
Length 469 ft
Breadth 41 ft
Draught 13 ft
Machinery 3 shaft Steam turbines, 51,000shp
Speed 33 knots
Range 5,500 miles at 14 knots
Armour 1.5" side, 1" deck
Armament 4 x 5.5" (4x1)

1 x 3" (1x1)

4 x 13.2mm (4x1)

AA 1939

8 x 76mm (4x2)

12 x 25mm (4x3)

As rebuilt to CLA

6 x 5" (3x2)

19 x 25mm (5x3 4x1)

Torpedoes 6 x 21" (2x3) nil 4 x 24" (1x4)
Complement 330
Notes IJN Tenryu
IJN Tatsuta

Decent photo of Tenryu in Yokosuka Harbour 1925.


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