IJN OOB Notes

[Subchaser]

IJN submarines.

Technical data correction

Type KD3A/B (Kaidai 3a/b)

- These boats had 6 forward torpedo tubes and 2 aft tubes, in game all 8 tubes are forward.

Type KD6A/B (Kaidai 6a/b)

- In game boats of this type have 6 forward tubes with 2 ammo, this should be changed to 4 forward tubes with 2 ammo and 2 aft tubes with 3 ammo. These boats carried 14 torpedoes not 12.
- Submarines I-171 - I-175 should have 4,7in/45 3YT gun instead of 3,9in/50 type 88.
- Submarines I-168 – I-173 should have 1 x 2x13,2mm type 93 AA mg, and I-174 – I-175 subs should have 2 x 2x13,2mm mgs.

Type KD5 (Kaidai 5)

- The same problem as with kaidai 6 type, there should be 4 forward tubes with 2 ammo and 2 aft tubes with 3 ammo.

Type KD7 (Kaidai 7)

- These subs had twin 25mm mount not single.

Type J1 (Junsen 1)

I-5, I-6 were the first Japanese submarines designed to carry an aircraft and if aircraft containers on I-5 were removed and additional gun was mounted in 1940, I-6 entered pacific war duly equipped for air reconnaissance missions.

- I-6 should have 1 aircraft capacity and 1 Glen float plane, 4 forward tubes with 3 ammo, 2 aft tubes with 3 ammo and one 4,7in/45 3YT gun.
- Subs I-2, I-4 and I-6 had one 13,2mm type 93 AA mg mount

Type J3 (Junsen 3)

- These subs carried 22 torpedoes not 18, torpedo ammo should be increased to 4.
- In game these subs have two twin 13,2mm mounts and one single 13,2mm mg, this should be changed to one twin 25mm mount, one twin and one single 13,2mm mgs mounts.

Type KRS (Kirai-sen)

- Durability should be changed from 20 to 24.

Type L4 (Vickers L3 Mod)

- ammo for 2 aft torpedo tubes tube must 1 instead of 2, this type has only 10 torpedoes.

Maneuverability of the following types should be changed (mvr ratings of US subs also should be also be changed):
Type STo – 51,
Type AM – 52,
Type A2 – 54,
Type A1 – 56,
Type B3/4 – 57,
Type B2 – 58,
Type B1 – 58,
Type C3/4 – 57,
Type C2 – 59,
Type C1 – 59,
Type KD7 – 63,
Type KD6A/B – 64,
Type KD5 – 65,
Type J3 – 58,
Type J1 – 63,
Type KRS – 59,
Type ST – 92,
Type STS – 95,
Type L4 – 73.

These are cosmetic changes actually, such characteristic as maneuverability doesn’t taken into account in WitP sub combat, in one of my ASW tests poorly trained MSW of Admirable class (exp below 40) was able to sink two ST submarines (exp 99/99, commanders were the best available) in one turn, their superb mvr ratings did not help. In reality subs of this type, with speed of 19 knots submerged could easily avoid such attacks, Admirable minesweepers were making less knots on surface than these subs submerged. Then I’ve tested sub on steroids, dur –99, mvr –99, speed –40, and under command of excellent skipper this sub also felt victim of mighty Admirable class… another evidence of fundamentally flawed ASW combat in WitP.

I would like to know how developers calculated mvr ratings of the submarines, there was a mistake somewhere in these calculations. BTW I also don’t think that maximum diving depth divided by 100 fully represents submarine durability characteristics.

OOB Corrections

Type K6 (Kaichu 6)
2 submarines are missing - RO-55 (Built at Tamano Zosensho shipyard, commissioned 23 april 1944) and RO-56 (Built at Tamano Zosensho shipyard, commissioned 5 july 1944).

Type C2 (Kaidai Hei-Gate C2)

I-49, I-50, I-51 - these are the phantom subs, none was even laid down. Order for them was really placed in 1941, under fleet replacement program, but it was canceled in may 1943. However these are in the game, this supposes that in game I-48 will be laid down in september ’43, I-50 in july ’43 and I-51 in february ’44. If these subs were included to beef up IJN submarine force in 1945, when it probably will be already mauled, then I must admit that this is strange choice. May be it would better to give player submarines which were really laid down and by spring ’45 were almost ready. I-404 was 95% ready when she was sunk by US carrier planes in Kure on 28 july ’45; I-1 (type AM) 70% ready; I-15 (type AM) 90% ready; I-204 90% ready; I-205 -80% ready; I-206 was 85% ready in march ’45 etc. Or to launch more perspective boats from the canceled order list than these kaidais in late 43, there were so many plans… any ideas?

Where is japanese transport submarine fleet?

28 IJN transport submarines are missing, (since IJA vessels are completely ignored there is no wonder why 26 army transport submarines also weren’t included).

The number of transport submarines Japanese built during the war and the number of subs converted ito undersea transports actually deserves additional ship type – SST, transport submarine.

Type Sen-Ho (2 subs - I-351, I-352)
Max Speed - 16
Cruise Speed - 10
Mvr - 59
Dur- 34
End- 27 500
Fuel- 750
Cap - 365 tons (FUEL)
Torps - 4x 21in type 95 –F (1)
AA guns - 2 x 3x25mm type 96 + 1 x 1x25mm type 96

Type Tei-Gata 2 (2 subs - I-373, I-374)
Max Speed - 13
Cruise Speed - 10
Mvr - 58
Dur - 33
End - 15 000
Fuel - 350
Cap - 120 (Supplies)
Naval guns - 1 x 5.5in/40 QF
AA guns - 1 x 2x25mm type 96

Type Tei-Gata (12 subs - I-361 – I-372)
Max Speed - 13
Cruise Speed- 10
Mvr - 58
Dur - 33
End - 15 000
Fuel - 350
Cap - 120 (Supplies)
Torps - 2 x 21in type 95 –F (1) only I-361
Naval guns - 1 x 5.5in/40 QF
AA guns - 1 x 2x25mm type 96

Type Sen-Yuso-Sho (12 subs - Ha-101 – Ha-112)
Max Speed - 10
Cruise Speed - 8
Mvr- 61
Dur - 31
End - 3 500
Fuel - 75
Cap - 60 (Supplies)
AA guns - 1 x 25mm type 96

As I said there were also 26 army sub transports (12 of Yu-1 type and 14 of Yu-1001 type).

Any comments, corrections… ideas?

[Brady]

Nicely done Subchaser.

[Subchaser]

Thanks Brady, it’s nice to know that at least one man read this. [:)]

[Subchaser]

Part 2. Minelayers

OOB corrections

Ikitsushima

Wrong refit. 3in/40 type 88 guns were replaced with 2 x 2x25mm AA guns before the war actually, not in 44. In 1944 ship was refitted in order to enlarge her mines holds, that was the main goal of the refit, in 1944 number mines was increased from 300 to 400, besides that 3 x 2x13,2mm AA mgs were added.

Ma-1

Mines type 4 (1944 design) should be replaced with type 93 mines.

Hatsutaka

Cruise speed should be 10 instead of 15. In 1943-44 must be refitted as escorts, mine laying equipment should be dismounted and 2 DCT should be installed (36 depth charges type 2)

Hirashima

Wrong refit. There should be no DCT in original minelayer configuration. And after refit 9/43 ships should have no minelaying capabilities, their endurance must be increased up to 5000 nm (with 55 fuel) 2x DCT (36 depth charges type 2) must be added.

Sokuten

Hirashima, Sokuten and Ajiro types were in fact one ML class – Sokuten. In wartime Japanese classification table they were all listed as Sokuten class ships (different replacement programs 3,4,5), multipurpose kaidai auxiliaries, capable to lay mines and nets of all types. If Hirashima class vessels are supposed to be refitted in game, why Sokuten class refit is not modeled? Sokutens were refitted in the same time as Hirashima class. In 9/43 configuration these ships should not have mines and instead should be equipped with 2 DTC (36 depth charges type 2).

Toshima

These ships represented in their 1944 configuration but without DTCs. In 1941 they should have 1x 3in/40 type 88 gun and 60 mines type 93, after refit in 1944 they should have 1x 3in/40 type 88 gun, 120 mines type 4, 4 DTC (18 depth charges type 2) and one twin 13,2mm AA mg.

Natsushima

Amalgamation of 3 ML classes - Nasami, Tsubame and Sarushima. Because of that, correct refit cannot be modeled. Kamome, Tsubame and Sarushima lost their mine laying equipment in 1944 and were refitted as escort vessels with 2 DTC (36 depth charges type 2).

Yaeyama

This ML was also converted in 1944. Mines hardware was removed and 2 DTC (36 depth charges type 2) installed.

Shirataka

If all previous types really were minelayers during the war, this ship became a patrol gunboat already in 1940. This ship should have only one 120mm gun and 6 DTC (54 depth charges type 95).

Katsuriki

Since 1936 Katsuriki was in service as an oceanographic vessel of navy department W, in january ’42 was refitted again, this time as an rescue ship. Probably should not be modeled at all.

Missing types

Hatsushima Class

These were probably not included because this type was designed as a cable layer type, but in fact these 4 ships were multipurpose and were capable to lay mines as well. The only problem was their awfully small mine holds, which were enlarged only in 1943-44.

Hatsushima – commissioned 10/1940, Kawasaki, Kobe
Tsurushima – commissioned 03/1941, Kawasaki, Kobe
Odate – commissioned 07/1941, Harima SB
Tateishi - commissioned 08/1941, Harima SB

1940-1943 (originally cable layers)
1564 / 1670 tons, 2 boilers x 2300 hp, 14 knots,
1 x 76mm/40 gun, 1 x 2x13,2mm MG, 12 mines

1943-1944 (converted to minelayers)
1 x 76mm/40 gun, 6 x 25mm AA cannons, 2 x DTC 36 depth charges type 2, 120 mines type 93.

Tateishi – 09/1943
Odate – 11/1943
Hatsushima – 2/1944
Tsurushima – 3/1944

Kamishima Class

Simplified version of Ajiro/Sakuten type, only 1 was built, order for 18 additional ships under 43/44 replacement program, was canceled.

Kamishima – commissioned 06/12/1945, Sasebo Arsenal K

766 / 787 tons, 2 x 1900 hp diesel. 16,5 knots
2x 40mm/40 guns, 3 x 3x25mm AA cannons, 4 x DTCs (36 depth charges type 2), 120 mines type 93.

Ajiro Class

One Sakuten class ML is missing. I guess it was not included since Ajiro never was a minelayer, when all other Sakutens were converted to escorts Ajiro was still under construction and it was decided to complete this unit as escort vessel also.

Ajiro – commissioned 7/1943, Hitachi, Innoshima

717 / 733 tons, 2 x 3600 hp diesel, 21 knots, fuel - 35 tons; endurance 2550 miles at 14 knots; Crew – 100; 1 x 76mm/40 gun; 2 x 3x25mm AA cannons; 2 x DTC (36 depth charges type 2.)

Transport-minelayers

Two standard transports completed as minelayers.

Eijo - (2-DRS class conversion) - commissioned 3/45, Kiangnan Dock, Shanghai
Mino - (2-DT class conversion) - commissioned 8/45, Naniwa Dock, Osaka

3224 / 5118 tons, 12 knots, 1 x 120mm/40 gun, 14 x 25mm AA cannons; 380 mines type 93.

[Bradley7735]

Subchaser,
I, for one, am VERY glad you are noting these OOB corrections. There are a lot of people who have allied OOB expertise, but there aren't very many who have IJA and IJN expertise. Even I realize that if we add more and more missing allied stuff, the game will get less and less chalenging for the allied player. I'm sure Pry will get all of these OOB changes logged. (I hope you can find missing BB's and CA's too) [:D]

But, I think you need to post the date that the missing transport subs come in to play. Other than that, I think your post is very easy to read and detailed.

bc

[Don Bowen]

This is indeed excellent data. I wonder if someone from Matrix could comment on the ability of the AI to use Cargo Submarines (those without any torpedo tubes).

[Oleg Mastruko]

Subchaser no one will notice your posts here (except for Brady of course [:D])

Post them in appropriate thread (OOB thread), or on the Support/Bug board, or mail them directly to the Ron Sauracker the OOB guy.

OR Team up with Lemurs! or someone, and make a new (modded) scenario.

Otherwise, it's really useless to post such long, detailed and informative posts only to see them fade away after a day or two as will inevitably happen...

Oleg

[Tanaka]

ORIGINAL: Bradley7735

Subchaser,
I, for one, am VERY glad you are noting these OOB corrections. There are a lot of people who have allied OOB expertise, but there aren't very many who have IJA and IJN expertise. Even I realize that if we add more and more missing allied stuff, the game will get less and less chalenging for the allied player. I'm sure Pry will get all of these OOB changes logged. (I hope you can find missing BB's and CA's too) [:D]

But, I think you need to post the date that the missing transport subs come in to play. Other than that, I think your post is very easy to read and detailed.

bc

Ditto here! Great Job Subchaser!!! [:D]

[Ron Saueracker]

Good stuff, Andrey!

I'm still waiting for a copy of Jordan's "Merchant Flleets 1939". Only one copy in Ottawa!! I want to go over the IJN merchant fleet issues at some point. EG., the Tonan Marus, converted whale factories, were much bigger than a large tanker. Also, many have suggested that Japan is potentially short some serious numbers of merchants which are not smaller than 3000 tons...I want to check on this.

[Subchaser]

(I hope you can find missing BB's and CA's too)

No BBs..unfortunately.. but there is one CVE, two CL and some other stuff… lots of the ships actually.

But, I think you need to post the date that the missing transport subs come in to play. Other than that, I think your post is very easy to read and detailed.

When it will be decided to include these subs I’ll post all needed data, right now it’s just a waste of time.

This is indeed excellent data. I wonder if someone from Matrix could comment on the ability of the AI to use Cargo Submarines (those without any torpedo tubes).

I believe AI won’t be able to use sub transports as it supposed, new ship type needed – submarine transport, otherwise AI will always try to put those into patrol TFs.

Post them in appropriate thread (OOB thread), or on the Support/Bug board, or mail them directly to the Ron Sauracker the OOB guy.

OR Team up with Lemurs! or someone, and make a new (modded) scenario.

Otherwise, it's really useless to post such long, detailed and informative posts only to see them fade away after a day or two as will inevitably happen...

I’m going to repost these notes in OOB thread, subs are already there. I’m making these notes while working on my scenario. Don’t worry I’ll try to keep these things on surface.

[Subchaser]

ORIGINAL: Ron Saueracker

Good stuff, Andrey!

I'm still waiting for a copy of Jordan's "Merchant Flleets 1939". Only one copy in Ottawa!! I want to go over the IJN merchant fleet issues at some point. EG., the Tonan Marus, converted whale factories, were much bigger than a large tanker. Also, many have suggested that Japan is potentially short some serious numbers of merchants which are not smaller than 3000 tons...I want to check on this.

This is a very good and hyperinformative book... congrats! [:)]

Did you get my pm Ron?

[Subchaser]

Amphibious and Landing Crafts

122 crafts of this type are missing… or better to say ignored.

T-1 Class (1st Class Fast Transports)

21+1 units: T-1 – T-22 (commissioned 4/44 – 5/45)



This type was designed in 1943 only for one task – supplying of isolated island garrisons in total enemy air and sea superiority conditions. Unique hull design allowed them to unload Daihatsu supply barges and supply containers at 16 knots speed without risk of damaging cargo.

Displacement – 1500/1770 tons; Dimensions – 96 x 10,2 x 3,6 meters; Power unit – 1 turbine, 2 boilers at 9500hp. Max Speed – 22,5 knots, cruise –15; Endurance – 4700 miles (18 knots), fuel- 300 tons. Armament (1943 project) – 1 x 127mm/40 gun + 3 triple 25mm mounts + 1 twin 25mm mounts + 4 single 25mm mount, Refit 1944 – 1 x 127mm/40 gun + 26 x 25mm guns in various configurations + 4 DTC (42 depth charge type 2) . Load – 500 tons of supplies + 480 men.

Type SS-1 Landing craft

22+5 units: SS-1 – SS-22 (commissioned 2/43 – 7/44) + 5 unfinished units

Japanese analog of LCM craft (even looked very much the same). Type was designed for Army, but all ships were under navy control.

Displacement – 933 tons, Dimensions – 63 x 9,6 x 2,8 meters. Power unit – 2 diesels 1800hp. Max Speed – 13,5 knots, cruise –12; Endurance – 2000 miles (12 knots). Armament – 1 x 76mm/40 gun + 1 mortar + 2 x 2x25mm. Load (project specification) – 4 x 15tons tanks + 1 transport vehicle + 150 men.

Type SB/SBD/SBT Landing craft

73 units: SBD type – 6 units commissioned in 1944, SBT type – 47 units commissioned 4/1944 – 3/1945, SB type – 20 units commissioned 5/1944 – 9/1944



Designed in late 1943 as SS-1 replacement type. By design and conception they were very close to LST-2 vessels, but a bit smaller and faster. Last letter in designation goes to type of the power unit, D for diesel and T for turbine. SB version ships were initially built for army but were transferred to navy in October 1944.

(SBT subtype) Displacement – 970/1004 tons, Dimensions – 80,5 x 9,1 x 2,9 meters. Power unit – 1 turbine, 2 boilers at 2500hp. Max Speed – 16 knots, cruise –14; Endurance – 2500 miles (14 knots). Armament – 1 x 76mm/40 gun + 2 x triple 25mm mount. Load – 218 tons of supplies, or 320 men, or 7 x 15tons tanks or 67 tons of cargo and 120 men.

Shinshu Maru

1 unit - commissioned in 1934.

First Japanese vessel designed for landing operations. Ship is in the game, but modeled as ordinary sAK. In fact she was designed as mothership vessel for smaller landing craft and as floatplane tender in the same time.

Displacement – 9000/11810 tons, Dimensions – 156 x 22 x 9 meters. 2 x turbines 8000hp, Max Speed – 19 knots, cruise – 12, Endurance – 16000 (at 9 knots) Armament – 8 x 76mm/40 gun + 3 x twin 25mm mount + 12 x 13,2mm AA mgs. 20 floatplanes (Shinshu Maru Daitai (!)), 2 catapults. Load – 29 Daihatsu landing barges and 2200 men.

Japanese thought that Shinshu Maru concept was quite successful and converted several standard transports into amphibious operations support ships, 7 ships total. 4 of these are in the game (as ordinary transports) Mayasan Maru, Tamatsu Maru, Hyuga Maru, Takatsu Maru, and 3 more are missing - Tokitsu Maru, Kibitsu Maru, Setsu Maru.

[Ron Saueracker]

ORIGINAL: Subchaser

ORIGINAL: Ron Saueracker

Good stuff, Andrey!

I'm still waiting for a copy of Jordan's "Merchant Flleets 1939". Only one copy in Ottawa!! I want to go over the IJN merchant fleet issues at some point. EG., the Tonan Marus, converted whale factories, were much bigger than a large tanker. Also, many have suggested that Japan is potentially short some serious numbers of merchants which are not smaller than 3000 tons...I want to check on this.

This is a very good and hyperinformative book... congrats! [:)]

Did you get my pm Ron?

Which one???? Not recently...

[Culiacan Mexico]

ORIGINAL: Subchaser

IJN submarines.

Any comments, corrections… ideas?

Comments? [X(]


Impressive is what comes to mind first.

[brisd]

Subchaser, very impressive. Thanks for posting all this data here and OOB thread. Did you have any info on IJN "AD" class ships? I believe there are three in the game and none to convert to, just curious.

[Subchaser]

ORIGINAL: Culiacan Mexico

ORIGINAL: Subchaser

IJN submarines.

Any comments, corrections… ideas?

Comments? [X(]

Impressive is what comes to mind first.

Thanks, I hope we will get a bit more accurate IJN OOB in the next patches… this is my goal actually.

[Subchaser]

ORIGINAL: brisd

Subchaser, very impressive. Thanks for posting all this data here and OOB thread. Did you have any info on IJN "AD" class ships? I believe there are three in the game and none to convert to, just curious.

I'll look into this... ADs are not easy subject to research

[Speedysteve]

Reminds me -

I swear I remember reading before that converted Large Jap tankers and large Allied Liners would be included. Can't see any? Am I mistaken?

Regards,

Steven

[Mr.Frag]

I'll look into this... ADs are not easy subject to research

While you are looking into that ... perhaps you can dig in a little deeper on *this*:

During the battles in the Solomons, obviously torpedoes were fired ... was there a AD at Truk or Rabaul?

I find it somewhat tough to believe that ships that used their torpedoes had to rotate back to Japan to get reloads.

[Brady]

"AD at Truk or Rabaul"


AD is quiet abstracted in the game realy, all that would be nescessary is a transport loaded with them to have deleaved some to the Harbor their.


...............................

"Reminds me -

I swear I remember reading before that converted Large Jap tankers and large Allied Liners would be included. Can't see any? Am I mistaken?

Regards,

Steven "

The closer you look at the shiping for bot sides the more generic it realy is up to a point, Many Japanese Ships are slower than they should be, many allied ones are faster and have larger capacitys than they did, but we see a lot of generic hull forms and capacitys in the game. Also scades of Ships are absent from both sides, While Subchaser is doing excelent work on highlighting some of the issues with the Japanese Fleat, their remain scores of other issues wich are likely to not be wholy resolved in the interest of easing game play. As an example we see the compleat absence of literly thousands of Ships types from the Japanese side in the game, ostensably to ease management (or so I suspect)...note I am stating the reasion for this (or what I preceave to be the reasion)...personaly I would rather see some of these types represented, particularly the Standaradised Merchant hull types built by Japan during the war.