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Japanese Lt Cruisers missing 3.1"/5" secondaries


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#1 vichussar

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Posted 20 October 2011 - 06:17 PM

Hii All,

Looking at the SSD's for the Nagara & Sendai class Lt cruisers I have noticed the following discrepencies
- The front turret is shown as "2" when it should "1" and "1" with second (B gun) behind the dotted line showing limited arc. I suspect this was done to save space but it allows 4 tubes (2d12) to fire over the bow when it should only be 3 (1d12).

- Both classes had a single 3.1" 40-cal AA gun (upsized to 5" 50-cal DP in 1943) each side of the second funnel just abaft the for'ard TT banks. These are missing from the SSD's. Which chart for the 3.1" and which 5" column on the IJN CRT would I use, the [5"~4.7"] or the [5"AA~3.9"]?

Regards
John Mc

#2 Cpt M

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Posted 21 October 2011 - 12:46 AM

Hii All,

Looking at the SSD's for the Nagara & Sendai class Lt cruisers I have noticed the following discrepencies
- The front turret is shown as "2" when it should "1" and "1" with second (B gun) behind the dotted line showing limited arc. I suspect this was done to save space but it allows 4 tubes (2d12) to fire over the bow when it should only be 3 (1d12).

- Both classes had a single 3.1" 40-cal AA gun (upsized to 5" 50-cal DP in 1943) each side of the second funnel just abaft the for'ard TT banks. These are missing from the SSD's. Which chart for the 3.1" and which 5" column on the IJN CRT would I use, the [5"~4.7"] or the [5"AA~3.9"]?

Regards
John Mc


The '2' for the forward mounts was necessary due to space concerns. However, your calculation of hit dice is slightly off. You need to total up all the tubes firing. So for 3 tubes firing forward, it would take 2D12, while 4 tubes forward also takes 2D12s.

According to several sources, the 3.1" AA guns were replaced with heavy MGs pre-war (the 3.1" being neither an effective AA gun nor surface combat gun). For the later fit with the 5" AA, use the 5" AA - 3.9" column.

#3 vichussar

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Posted 21 October 2011 - 01:36 AM

The '2' for the forward mounts was necessary due to space concerns. However, your calculation of hit dice is slightly off. You need to total up all the tubes firing. So for 3 tubes firing forward, it would take 2D12, while 4 tubes forward also takes 2D12s.


According to several sources, the 3.1" AA guns were replaced with heavy MGs pre-war (the 3.1" being neither an effective AA gun nor surface combat gun). For the later fit with the 5" AA, use the 5" AA - 3.9" column.


Ooops, I forgot you round down for triple turrets but up for single tubes.

On further checking the 5"/50-cal DP is the same gun fitted to the Fubuki and Kagero destroyers so may be the 5"~4'7" chart is more appropriate also this will avoid the Rapid Fire ability. BTW my main source is "Warships of the Imperial Japanese Navy 1869-1945, by Jentschura, Jung, and Mickel".

#4 Cpt M

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Posted 22 October 2011 - 11:46 AM

Ooops, I forgot you round down for triple turrets but up for single tubes.

On further checking the 5"/50-cal DP is the same gun fitted to the Fubuki and Kagero destroyers so may be the 5"~4'7" chart is more appropriate also this will avoid the Rapid Fire ability. BTW my main source is "Warships of the Imperial Japanese Navy 1869-1945, by Jentschura, Jung, and Mickel".

In this case, Jenschura, et al are incorrect (not so much an error as being superseded by later research). The following is from "Japanese Cruisers of the Pacific War" by Lacroix and Wells (unquestionably the best source to date on the IJN's cruisers in WWII).

Generally from late 1943 on, the surviving older crusiers of the Kuma and Nagara classes had one of their 5.5"/50 replaced with one 5"/40 Type 89 twin AA mount. Of the Kumas, Kiso and Tama were refitted in late 1943, while of the Nagaras, all except Yura (which had been lost in 1942) received the same refit from early 1943 to early 1944 (Isuzu received an additional 3 mounts in late 1944). Kitakami received 2 Type 89 mounts during her 1944 conversion to a Kaiten carrier. Of the Sendai class, only Naka received a Type 89 mount (replacing a 5.5"/50 in early 1943).




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