Bottlenecks Mod: Updated Jan 16, 2026
Posted: Sat Apr 01, 2017 5:55 pm
For those interested in “historic” mods, I hereby present you an enhanced version of “DaBigBabes” scenario 29C.
The overall goal of my mod is to slow down the pace of the game and to add missing historic ships and units.
Some key features:
• Downsized base sizes and potential bases sizes of many bases > slows loading/unloading, requires more time-consuming construction efforts, prevents unrealistically large “monster bases“ in hostile terrain/climate, unrealistic port sizes etc.
• Added many bases and dots to CBI theater, PI, Solomons / Papua / Northeaster New Guinea / Dutch New Guinea / New Britain / Admiralty Is. / Northern Australia and Queensland areas and even Japan
• Dot bases in China have a garrison requirement for Japan which should make it much more difficult for Japan to advance deeply into China and keep the rear area under control
• Bases and dot bases throughout Asia, esp. along railroads / roads, have supply caps to represent poor transport infrastructure > bad or lack of roads, low capacity railways (as compared to the good infrastructure in CONUS for example
• Downsizing of road network in Asia
• Eliminated river crossings of the lower Jangtze River, Gulf of Martaban (north of Moulmein) and Brahmaputra (Assam Railroad) since bridges did not exist at these places until after the war > interrupts strategic movement of troops and thus slows down the railroad blitzkrieg.
• To model the “on a shoe-string” condition of the Allies in regards to military supplies at the beginning of the war and the rising production over time, many Allied light industries and resource centers start 33% - 50% damaged. No 1945 production levels from Day 1!
• Got rid of most of the “first turn movement bonus” TFs and ahistorical pre-set invasion TFs intended to help the AI – this is a no-AI scenario anyway
• Force Z starts at Singers with no orders - instead of being sent to auto-demise at the hand of Netties from Saigon). Historically it left Singers on Dec 8th so players should have the choice where to send it.
• Manila subs are not waiting to be sunk by a first-turn port strike – IMO that popular opening move is a silly “20:20 hindsight” exploit, as much as first-turn carrier hunting. Most of them are assigned to TFs – it’s an Dec 7th PM scenario and after the Clark Field strike they got orders to move or pull the plug to hide
• Lots of ships added - including hospital ships, tugs, net layers, patrol yachts, small fry - but also elimination of duplicate ships
• Ground forces OOB changes and additional units - Railroad Engineers, POW Labor units, civilians, even yummy nurses!
• Some GUI improvements to ease identification of TF types and key assets
and much more...
Please find more details about the "mod philosophy", the changelog and screenshots in the documentation.
Installation:
• Backup your files or use a fresh install / copy of the base game
• Download installation files - six zip files total.
https://www.dropbox.com/sh/41coc4t6h8hm ... O6p0a?dl=0
• Unzip the files into a temp folder, then copy&paste the files into the appropriate game folders: Pwhexdat into the main / root folder of the game, Scen file in the SCEN folder, the four art packets into the ART folder. Overwrite = yes.
Scenario variants:
With the stock R&D model, the Japanese player can advance the availability dates of late-war plane models by several months if not years, for example opposing the Allies with hordes of Zero M8 and Frank-r by 1943.
This is unrealistic and a major gripe for many Allied players.
Since the philosophy of this mod is "more historically accurate (personal bias and all)", I will try to limit the unrealistic advancement of late-war plane types.
Furthermore, Japanese aircraft and engine production requires considerable management efforts, something which discourages many players from playing Japan.
Personally, I do not relish the engine management part of the game, however, other players may prefer to micromanage and optimise production.
Consequently, I propose two scenario variants:
# Scenario 059 “Standard R&D”
- Normal engines i.e. Ha-35, Ha-45 etc. are being used like in stock, but modded nonetheless - newer engine generations (which tend to be larger and more complex) are more expensive to produce due to higher supply costs for repairing (expanding) engine factories. This should apply a little brake on the numbers of late-war planes Japan may churn out earlier than historical.
- all R&D factories available
# Scenario 061 “Simplified Production”
- limited R&D, only plane models actually under R&D in Dec 1941 and only the first version of a model line has a R&D factory assigned, e.g. there is a R&D factory for the Jill B6N1, but none for the Jill B6N2 > this reduces the number of available R&D factories to just 18
- the super-numerous R&D factories are now production factories, set to produce 0 units per month of a fictional "plane" called "R&D / Preprod setup". The JFB player can change these factories to produce airframes of new types becoming available
- all Japanese plane models except those using jets, rockets and 'foreign engines' use a generic "engine" device, just like the Allied planes do > no more engine management!
- research engine factories become available at the appropriate date (e.g. the "Ha-60" becomes the "10/42" engine and the factory can be switched to produce "engine" devices in 10/42) > Samurai hono(u)r demands that engine research remain untouched, i.e. no switching of late-war factories to the earliest date available
- to offset the now easier / more efficient engine production, repair costs for engine factories have been doubled to 2000 supplies / point - so be careful not to over-extend!
- in consequence Japanese players still have some R&D capacity, but face far tougher choices and a limited capacity to churn-out large numbers of late-war planes much earlier
Changes in v1.1:
• economy revamped - see post on page 3 of this thread
• squad numbers for "Civilians" units reduced (the defense put-up by "civilians" was too strong in v1.0)
• fixes a few pwhexdat issues concerning wrong terrain / hexsides
• fixes various glitches with wrong ship upgrade paths and wrong LCU TOEs
• adds more new ships and corrected data of existing ships
• corrections to historic ship arrival / withdrawal dates (the OOB is very inaccurate in this regard - work in progress)
• some changes to base sizes, for example further downsizing in the Aleutians west of Dutch Harbor.
• some modifications to certain plane models (stats, upgrade paths)
• as an experiment, added "depth bombs" to certain aircraft: Jake, Kingfisher, dedicated ASW versions of Ventura, Liberator, Wellington ("GR" designations)
Changes in v1.2:
• corrections of glitches introduced in v1.1 [:o]
• more corrections to ship data, e.g. class, start location and crew exp of US Coast Guard cutters - thx to Spence for the hint
• adds "Fletcher Scout" ship class equipped with a floatplane and corresponding ships and air groups - thx to m10bob for the hint
• adds aircraft weapon filters and "bomb sticks"
• corrections to plane engines: adds Ha-36 Mamoru for B6N1 Jill, K-67 now uses Ha-42
• changes to A6M Zero line: new sub-models and revised stats to reflect incremental updates of protection and armament
• payload changes to fighters, fighter-bombers and attack bombers > can now use air-to-ground rockets
• Navy/Marine PBJ and PV-2 are now classified as attack bombers
• adding "Black Cats" and SB-24 "Snooper" planes and air groups specialised in night low altitude attacks
• other minor stuff and cosmetic changes
• Introducing new glitches [:'(] (corrected via hotfix)
Changes in v1.3:
• Fixed a number of database glitches introduced in previous versions, for example some Zeros having different 20mm canon models on normal range and on extended range
• Fixed SWPac HQ being "not in play" – now it is
• Added missing art file for Hashima class netlayer
• Added missing late-war IJN oiler Hario
• Added missing late-war IJN minelayers of the Minoo and Kamishima classes
• Corrected classes for oilers Kazahaya and Hayasui - Hayasui gains the missing flight deck and float planes to become a “MAC” ship
• Corrected Akitsu Maru: Was used as assault ship and aircraft ferry > can instant-convert between LSD (many troops, few planes) and AKV (few troops, many planes). Can upgrade the "flying-off platform" to full flight deck to operate Ki-76 and Ka-1, which she apparently did IRL (but ship remains LSD type, not being a full CVE)
• Corrected Nitsigu Maru: Apparently she did not have a "flying-off platform" > new class and art file. Has conversion option to become a "flight deck LSD" like Akitsu Maru.
• Corrected speed of the 4-stackers-converted-to-Banana-boats - they could make only 16kn, not 27kn.
• Modified the endurance of the Bangor and Bathurst classes, they seemed to be too short-legged in DBB
• Minor name changes of devices and units to help with "unit organization" in the game resp. working in the editor, e.g. Dutch air groups, civilians, mine devices
• Corrected USS Colorado engine damage bug which kept her stuck under shipyard repairs forever
• More corrections to ship arrival dates and locations, esp. US submarines (data from DANFS)
• Renaming of bases with "coordinates names" like “81/52" to names of existing locations within the hex area
• Major review of base sizes / potential bases sizes and supply cap values for more coherence concerning terrain type and transportation network. Supply caps also have been too generous in the previous versions of my mod IMO, they are now more in line with the "bottlenecks" philosophy.
• In this context I have added a few more bases in the Burma area to "strangle" supply flows (the necessary base slots have been taken from Russia, which usually enters the game late or not at all).
• Added the base "Namtu / Bawdwin" northwest of Lashio with a railway connection to the Mandalay-Lashio line. In the early 1900s and before World War II, the Bawdwin mine was the world’s largest source of lead and one of its main sources of silver and a major supplier of zinc. In the 1920s and 30s, it was said to be the richest mine in the British Empire. Reason enough for me to put it on the map (similar reasoning as for the Bukit Besi / Dungun base ("Iron Hill") I have added in Malaya).
• Changed the aggression stats of US sub skippers Voge and Grenfell as I feel the original values were too low. Voge made four successful patrols, was awarded the Navy Cross, the Bronze Star Medal with Combat “V”, and also received a Letter of Commendation with authorization to wear the Commendation Ribbon and Combat “V” for them, then became operations officer for COMSUBPAC - yet DBB gave him only 32 agg. Grenfell made two successful patrols, was awarded a Navy Cross and a Silver Star for them, after the war made Admiral and the only one to have been COMSUBPAC and COMSUBLANT. Yet DBB gives him only 50 agg. I have upped both into the 60s range.
• fix for aircraft durability errors
• fix for missing railroad in China north of Pengpu
Changes in version 1.4 (2026A):
• corrected duplicate B-17 slots
• fixed recombination error of NZ division
• tweaks to road network in Malaya
• tweaks to base sizes / supply caps
• Singapore now light urban terrain to reduce defensive terrain bonus - balancing, in several tests / games I have had trouble capturing it with larger than historic forces and later than historic
• changed Clark back to clear terrain - same reason as for Singapore, balancing US-Phi defence which I found too effective with jungle terrain def bonus
• fixed withdrawal date error for AK Betelgeuse
• corrected Mine Mark 18 not being produced because set to 'can build = no' by error
• Mine Mark 6 set to produce 300 per month for the duration of the war - historic starting pool was 59.000 (!) and it remained in the USN inventory until 1985
• upped loading capacity of Daihatsu barges to be able to transport motorised support and light / medium tanks
• corrected industry slots error rendering certain bases immune for city bombing
• corrected Wasp air-group resizing error in order to stay with air capacity
• corrected error rendering base immune for ambhib attack - can't remember which one, I think is was Cape D'Urville
• corrected VP value of Mengtze base (5, not 50)
• Command HQ designations have now a marker for easier identification. Two stars ** in front of the name indicate a "high-end" Command HQ attached to itself, one star in front of the name indicates a Command HQ attached to an high-end Command HQ
• number of Japanese pilots in pools at start greatly reduced as Japan had gone "all in" and there was practically no reserve of trained pilots
• number of US pilots in pools at start have been increased, because US started to train more pilots in 1939 and 1940 due to events in Europe
• revised garrison requirements in India - only cities important enough to have their names shown on the map retain / gain a garrison requirement. At-start movement orders for garrison units adjusted.
• switch to Bellum Pacifica extended map v3, with some terrain modifications, but without the map symbols (oïl, repair yards etc.) I had added on the v2 version. Too much work to redo and v3 has introduced some map symbols in a better way.
• only two scenario versions maintained, the "standard R&D" with the usual plethora of different Japanese engines and full R&D, and the "simplified production" version with generic "engine" device for Japanese planes and limited R&D.
Feel free to plunder ideas and data for your own mods. Questions and feedback welcome. Do not hesitate to point out errors, misconceptions, improvements etc.
Cheers,
LargeSlowTarget
The overall goal of my mod is to slow down the pace of the game and to add missing historic ships and units.
Some key features:
• Downsized base sizes and potential bases sizes of many bases > slows loading/unloading, requires more time-consuming construction efforts, prevents unrealistically large “monster bases“ in hostile terrain/climate, unrealistic port sizes etc.
• Added many bases and dots to CBI theater, PI, Solomons / Papua / Northeaster New Guinea / Dutch New Guinea / New Britain / Admiralty Is. / Northern Australia and Queensland areas and even Japan
• Dot bases in China have a garrison requirement for Japan which should make it much more difficult for Japan to advance deeply into China and keep the rear area under control
• Bases and dot bases throughout Asia, esp. along railroads / roads, have supply caps to represent poor transport infrastructure > bad or lack of roads, low capacity railways (as compared to the good infrastructure in CONUS for example
• Downsizing of road network in Asia
• Eliminated river crossings of the lower Jangtze River, Gulf of Martaban (north of Moulmein) and Brahmaputra (Assam Railroad) since bridges did not exist at these places until after the war > interrupts strategic movement of troops and thus slows down the railroad blitzkrieg.
• To model the “on a shoe-string” condition of the Allies in regards to military supplies at the beginning of the war and the rising production over time, many Allied light industries and resource centers start 33% - 50% damaged. No 1945 production levels from Day 1!
• Got rid of most of the “first turn movement bonus” TFs and ahistorical pre-set invasion TFs intended to help the AI – this is a no-AI scenario anyway
• Force Z starts at Singers with no orders - instead of being sent to auto-demise at the hand of Netties from Saigon). Historically it left Singers on Dec 8th so players should have the choice where to send it.
• Manila subs are not waiting to be sunk by a first-turn port strike – IMO that popular opening move is a silly “20:20 hindsight” exploit, as much as first-turn carrier hunting. Most of them are assigned to TFs – it’s an Dec 7th PM scenario and after the Clark Field strike they got orders to move or pull the plug to hide
• Lots of ships added - including hospital ships, tugs, net layers, patrol yachts, small fry - but also elimination of duplicate ships
• Ground forces OOB changes and additional units - Railroad Engineers, POW Labor units, civilians, even yummy nurses!
• Some GUI improvements to ease identification of TF types and key assets
and much more...
Please find more details about the "mod philosophy", the changelog and screenshots in the documentation.
Installation:
• Backup your files or use a fresh install / copy of the base game
• Download installation files - six zip files total.
https://www.dropbox.com/sh/41coc4t6h8hm ... O6p0a?dl=0
• Unzip the files into a temp folder, then copy&paste the files into the appropriate game folders: Pwhexdat into the main / root folder of the game, Scen file in the SCEN folder, the four art packets into the ART folder. Overwrite = yes.
Scenario variants:
With the stock R&D model, the Japanese player can advance the availability dates of late-war plane models by several months if not years, for example opposing the Allies with hordes of Zero M8 and Frank-r by 1943.
This is unrealistic and a major gripe for many Allied players.
Since the philosophy of this mod is "more historically accurate (personal bias and all)", I will try to limit the unrealistic advancement of late-war plane types.
Furthermore, Japanese aircraft and engine production requires considerable management efforts, something which discourages many players from playing Japan.
Personally, I do not relish the engine management part of the game, however, other players may prefer to micromanage and optimise production.
Consequently, I propose two scenario variants:
# Scenario 059 “Standard R&D”
- Normal engines i.e. Ha-35, Ha-45 etc. are being used like in stock, but modded nonetheless - newer engine generations (which tend to be larger and more complex) are more expensive to produce due to higher supply costs for repairing (expanding) engine factories. This should apply a little brake on the numbers of late-war planes Japan may churn out earlier than historical.
- all R&D factories available
# Scenario 061 “Simplified Production”
- limited R&D, only plane models actually under R&D in Dec 1941 and only the first version of a model line has a R&D factory assigned, e.g. there is a R&D factory for the Jill B6N1, but none for the Jill B6N2 > this reduces the number of available R&D factories to just 18
- the super-numerous R&D factories are now production factories, set to produce 0 units per month of a fictional "plane" called "R&D / Preprod setup". The JFB player can change these factories to produce airframes of new types becoming available
- all Japanese plane models except those using jets, rockets and 'foreign engines' use a generic "engine" device, just like the Allied planes do > no more engine management!
- research engine factories become available at the appropriate date (e.g. the "Ha-60" becomes the "10/42" engine and the factory can be switched to produce "engine" devices in 10/42) > Samurai hono(u)r demands that engine research remain untouched, i.e. no switching of late-war factories to the earliest date available
- to offset the now easier / more efficient engine production, repair costs for engine factories have been doubled to 2000 supplies / point - so be careful not to over-extend!
- in consequence Japanese players still have some R&D capacity, but face far tougher choices and a limited capacity to churn-out large numbers of late-war planes much earlier
Changes in v1.1:
• economy revamped - see post on page 3 of this thread
• squad numbers for "Civilians" units reduced (the defense put-up by "civilians" was too strong in v1.0)
• fixes a few pwhexdat issues concerning wrong terrain / hexsides
• fixes various glitches with wrong ship upgrade paths and wrong LCU TOEs
• adds more new ships and corrected data of existing ships
• corrections to historic ship arrival / withdrawal dates (the OOB is very inaccurate in this regard - work in progress)
• some changes to base sizes, for example further downsizing in the Aleutians west of Dutch Harbor.
• some modifications to certain plane models (stats, upgrade paths)
• as an experiment, added "depth bombs" to certain aircraft: Jake, Kingfisher, dedicated ASW versions of Ventura, Liberator, Wellington ("GR" designations)
Changes in v1.2:
• corrections of glitches introduced in v1.1 [:o]
• more corrections to ship data, e.g. class, start location and crew exp of US Coast Guard cutters - thx to Spence for the hint
• adds "Fletcher Scout" ship class equipped with a floatplane and corresponding ships and air groups - thx to m10bob for the hint
• adds aircraft weapon filters and "bomb sticks"
• corrections to plane engines: adds Ha-36 Mamoru for B6N1 Jill, K-67 now uses Ha-42
• changes to A6M Zero line: new sub-models and revised stats to reflect incremental updates of protection and armament
• payload changes to fighters, fighter-bombers and attack bombers > can now use air-to-ground rockets
• Navy/Marine PBJ and PV-2 are now classified as attack bombers
• adding "Black Cats" and SB-24 "Snooper" planes and air groups specialised in night low altitude attacks
• other minor stuff and cosmetic changes
• Introducing new glitches [:'(] (corrected via hotfix)
Changes in v1.3:
• Fixed a number of database glitches introduced in previous versions, for example some Zeros having different 20mm canon models on normal range and on extended range
• Fixed SWPac HQ being "not in play" – now it is
• Added missing art file for Hashima class netlayer
• Added missing late-war IJN oiler Hario
• Added missing late-war IJN minelayers of the Minoo and Kamishima classes
• Corrected classes for oilers Kazahaya and Hayasui - Hayasui gains the missing flight deck and float planes to become a “MAC” ship
• Corrected Akitsu Maru: Was used as assault ship and aircraft ferry > can instant-convert between LSD (many troops, few planes) and AKV (few troops, many planes). Can upgrade the "flying-off platform" to full flight deck to operate Ki-76 and Ka-1, which she apparently did IRL (but ship remains LSD type, not being a full CVE)
• Corrected Nitsigu Maru: Apparently she did not have a "flying-off platform" > new class and art file. Has conversion option to become a "flight deck LSD" like Akitsu Maru.
• Corrected speed of the 4-stackers-converted-to-Banana-boats - they could make only 16kn, not 27kn.
• Modified the endurance of the Bangor and Bathurst classes, they seemed to be too short-legged in DBB
• Minor name changes of devices and units to help with "unit organization" in the game resp. working in the editor, e.g. Dutch air groups, civilians, mine devices
• Corrected USS Colorado engine damage bug which kept her stuck under shipyard repairs forever
• More corrections to ship arrival dates and locations, esp. US submarines (data from DANFS)
• Renaming of bases with "coordinates names" like “81/52" to names of existing locations within the hex area
• Major review of base sizes / potential bases sizes and supply cap values for more coherence concerning terrain type and transportation network. Supply caps also have been too generous in the previous versions of my mod IMO, they are now more in line with the "bottlenecks" philosophy.
• In this context I have added a few more bases in the Burma area to "strangle" supply flows (the necessary base slots have been taken from Russia, which usually enters the game late or not at all).
• Added the base "Namtu / Bawdwin" northwest of Lashio with a railway connection to the Mandalay-Lashio line. In the early 1900s and before World War II, the Bawdwin mine was the world’s largest source of lead and one of its main sources of silver and a major supplier of zinc. In the 1920s and 30s, it was said to be the richest mine in the British Empire. Reason enough for me to put it on the map (similar reasoning as for the Bukit Besi / Dungun base ("Iron Hill") I have added in Malaya).
• Changed the aggression stats of US sub skippers Voge and Grenfell as I feel the original values were too low. Voge made four successful patrols, was awarded the Navy Cross, the Bronze Star Medal with Combat “V”, and also received a Letter of Commendation with authorization to wear the Commendation Ribbon and Combat “V” for them, then became operations officer for COMSUBPAC - yet DBB gave him only 32 agg. Grenfell made two successful patrols, was awarded a Navy Cross and a Silver Star for them, after the war made Admiral and the only one to have been COMSUBPAC and COMSUBLANT. Yet DBB gives him only 50 agg. I have upped both into the 60s range.
• fix for aircraft durability errors
• fix for missing railroad in China north of Pengpu
Changes in version 1.4 (2026A):
• corrected duplicate B-17 slots
• fixed recombination error of NZ division
• tweaks to road network in Malaya
• tweaks to base sizes / supply caps
• Singapore now light urban terrain to reduce defensive terrain bonus - balancing, in several tests / games I have had trouble capturing it with larger than historic forces and later than historic
• changed Clark back to clear terrain - same reason as for Singapore, balancing US-Phi defence which I found too effective with jungle terrain def bonus
• fixed withdrawal date error for AK Betelgeuse
• corrected Mine Mark 18 not being produced because set to 'can build = no' by error
• Mine Mark 6 set to produce 300 per month for the duration of the war - historic starting pool was 59.000 (!) and it remained in the USN inventory until 1985
• upped loading capacity of Daihatsu barges to be able to transport motorised support and light / medium tanks
• corrected industry slots error rendering certain bases immune for city bombing
• corrected Wasp air-group resizing error in order to stay with air capacity
• corrected error rendering base immune for ambhib attack - can't remember which one, I think is was Cape D'Urville
• corrected VP value of Mengtze base (5, not 50)
• Command HQ designations have now a marker for easier identification. Two stars ** in front of the name indicate a "high-end" Command HQ attached to itself, one star in front of the name indicates a Command HQ attached to an high-end Command HQ
• number of Japanese pilots in pools at start greatly reduced as Japan had gone "all in" and there was practically no reserve of trained pilots
• number of US pilots in pools at start have been increased, because US started to train more pilots in 1939 and 1940 due to events in Europe
• revised garrison requirements in India - only cities important enough to have their names shown on the map retain / gain a garrison requirement. At-start movement orders for garrison units adjusted.
• switch to Bellum Pacifica extended map v3, with some terrain modifications, but without the map symbols (oïl, repair yards etc.) I had added on the v2 version. Too much work to redo and v3 has introduced some map symbols in a better way.
• only two scenario versions maintained, the "standard R&D" with the usual plethora of different Japanese engines and full R&D, and the "simplified production" version with generic "engine" device for Japanese planes and limited R&D.
Feel free to plunder ideas and data for your own mods. Questions and feedback welcome. Do not hesitate to point out errors, misconceptions, improvements etc.
Cheers,
LargeSlowTarget
