Dutch submarines stop Japanese Invasion fleet in 1942

All of this is absolutely insufficient because the newer Japanese transports (Hikawa Maru, Akagi Maru and such) were designed for speeds of 18-20 knots. You need at least 27-knot submerged speed capable submarines (comparable to Soviet November-class of 1957) to make ideas of intercepting and annihilating the Japanese transport convoys workable, even with aerial scouting. Actually aerial scouting would be of limited use too, because the Japanese were also invested heavily in long-range fighters (Ki-43 and A6M), and with rudimentary radar tech of 1941, the tracking of convoys from air at night was close to impossible, and unreliable in case of even cloudy weather. Simply if weather is good, your scout planes are shot down. If weather is bad, your scout planes are useless.

I understand this is a outright Dutch wank, but i.m.h.o. the most realistically engagement will not go the way you depicted, even if we assume the 8-knot speed of Japanese convoy is true (11-12 knots may be more appropriate given the circumstances of weather and relatively short route)
Most likely outcome is "after short-range torpedo from sweep has hit and damaged the light cruiser Naka, the Dutch submarines have failed to score any hits, being too busy trying to outmaneuver the escorts and get into firing positions. All torpedoes subsequently fired from long distances have failed to hit the targets."

Trurle:
Thank you for your reply, only disappointing you call it a wank, which it isn't.
First the strategy to use submarines as a main weapon to destroy military transport fleets in the Sea Straits approaching Java was real, conceived just after the Great War and was the main strategy for the next two decades.
Hence the fact that the Royal Dutch Navy had a very small number of very light cruisers and destroyers. The cruisers were only to protect the destroyers against enemy destroyers. Dutch destroyers were caring float planes, their main objective was to scout for the submarines. The relative large number of submarines.

Second the tactic to execute the strategy was developed and extensively trained during the next two decades. The last Division-Roedel exercise was performed in the summer of 1940.
The reason this strategy and tactic was abandoned, was due to the personal vision of the commander of the Dutch Royal Navy at that crucial time; Admiral Furstner. He was advocate of navalism, and for this reason he put all Dutch submarines under British command who, in line with their WW1 doctrine sent the submarines on solo mission with out any scouting of other submarines, surface vessels or airplanes. Admiral Furstner refused to send the submarines originally based in the Netherlands, the O-class boat, to reinforce the K -boats in the far East as was part of the submarine strategy.

The number of destroyed transport ships are based on the exceptional high hit rate in one attack of the O-16 (4 transports destroyed and 2 damaged) and the K-XIV (4 transports destroyed)

I am optimistic of the attrition rate even the Dutch doctrine was firing at a very close range with the calculated risk of being destroyed. On the other hand Dutch submarines would attack submerged when ever possible, and preferably at night. The Japanese submarine chaser and patrol boat were WW1 era destroyers and small versions of destroyers. There only weapon as with other navies at that time was throwing of depth charges at the estimated location of the submarine. . Use of active hydrophones (sonar) to locate enemy submarines was only later used by the Allies.

I am not arguing the fact that some transport ships could make 27 knots, the war ships of that time could make 32 knots. However this speed burns a lot of fuel.
There many other ships in the convoy who were not as fast and these slower ships determine the maximum speed of the fleet.
The Fleet was navigating in seas occupied by the enemy with risk of mine and non chartered sub-sea rocks. ( this was hitting an USS destroyer OTL)
The light cruiser "Naka" was destroyed in TL since it was part of the Japanese 4th destroyer flotilla. The Naka was a light cruiser, not a heavy armored battles ship, which made it plausible it could be destroyed by a salvo of 4 torpedo's from the bow as the Dutch submarines had. The attack of a Divison-roedel took place with 4 boats, each boat took its own target, which make it plausible that the first salvo's were hits and after the attack the boats would retreat in there attempt to avoid detection and destruction.

Your other argument was that Dutch subs are too slow and there for could not hit fast ships.
Dutch submarine resembled the German VIIB/C class with nearly the same speed. The kill rate of these 17 knot surface, 8 knot submerged boats was enormous it nearly brought Britain to starvation in 1940. The kill rate of the slightly larger and faster USS submarines was even higher and did starve Japan, but their speed never came higher than 21 knot surfaced.
The whole principle of submarines attack is not to out run enemy ships but to encounter them.
The hunting grounds of the Dutch submarines tactic were the Sea Straits of the Indonesian archipelago, which still are vast but are narrowed by numerous island within the straits.
Despite the heavy investment in long range fighters as you stated and the absence of radar or other sophisticated technologies, gave the reconnaissance planes on both sides during WW2 in the pacific a quit good detection score, without being shot down by sudden appearing long range fighters. You forget that the skies and seas are very large and that fighters did not have radar in 1941/1942 as well.
 
Very good, Parma...

...In a wank, one side curbstomps the other with few or no losses. Personally I prefer the use of technical advances to sway the outcome, but still with significant damage to Our Heros.
 
Long term (possible) Aftermath:
During the whole year of 1942 the Faith of Singapore and Java and Sumatra were in the balance.
At two occasions the Japanese invasion fleets were encountered. In the Flores Sea, Between Flores and Celebes. This was a major but hard fought victory, were the Japanese air force from their Navy and Army caused a lot of difficulties and losses among the Allies. Never the less, despite heavy losses, the losses of the Japanese invasion army was so much, due to the destruction of complete army units in their transports that an invasion of Java was not feasible any more.

upload_2018-10-23_11-34-46.png


Destruction of supply ships by Dutch and American submarines to the Japanese troops on Celebes gave the Australian and KNIL troop during the course of 1942 the upper hand. The disruption of the supply lines of the Japanese Army besieging Singapore gave the British Commonwealth troops during 1942 also the upper hand on the Malayan peninsula.
The shift in focus of the Japanese Imperial fleet to the American Aircraft carriers accumulating in the Battle for Midway, and the destruction of the Japanese Aircraft carriers gave the ground forces of the Allies the final upper hand. However they were not near of being able to force a counter offensive. The Japanese were mere in the defence and very slowly had to gave ground away in Borneo, Malaya and Celebes.
The focus of the British and Americans was still, first the destruction of NAZI Germany and then Imperial Japan.

For Dutch East Indies this long defensive war mean the following.
The Indonesian Nationalist, PNI, split apart in members supporting the fight against Japan and others who thought to see an opportunity to topple the colonial rule.
This led to some insurgencies which were not successful but led to the death or executions of several prominent members of the PNI amoung Mr Soekarna andn Hatta.
Soetan Sjahrir on the other hand was part of the PNI faction who cooperated with the fight against the Japanese. He would become the first chairman of the "Volksraad" of the Indonesian Federation after the war.
The KNIL consisted of mostly men from the Molucca's and Ambon. Initially they were only soldiers and NCO's only Europeans and Indo's ( half european half Indonesian) were officers. Due to the pressure on personnel many of the initial KNIL soldiers and NCO's made promotion to officers.The Indo's were the population group who benefit the most of the shortage in personnel and who were the most dominant population group in nearly all mid and high ranking functions of the military and civilian life.
The Commander of the KNIL General Berenshot was Indo him self and many Aces of the Air force were also Indo's. In late 1942 the segregation was abolished.
BY the end of 1942 the B-10 of the Royal Dutch Indonesian Air force were replaced by modern B-25 while the fighters were replaced by P-36/75 and P-40.
By 1943 the Dutch navy was reinforced with the light cruisers Eendracht and Zevenprovincien despite shortage of personnel. The lost submarines were replaced by American build Gato-class boats.
 

trurle

Banned
Your other argument was that Dutch subs are too slow and there for could not hit fast ships.
Dutch submarine resembled the German VIIB/C class with nearly the same speed. The kill rate of these 17 knot surface, 8 knot submerged boats was enormous it nearly brought Britain to starvation in 1940. The kill rate of the slightly larger and faster USS submarines was even higher and did starve Japan, but their speed never came higher than 21 knot surfaced.
Well, the US submarine navy in its height of operations in 1944 was able to inflict something like 10% attrition to Japanese per month, with most critically intercepting and decoding Japanese ratio. You, on other hand, aim for something like 40% per month, with much smaller and less capable submarine fleet and without broken radio codes. This is called "wishful thinking" or "wank".
To be realistic, try to keep fighting with 3% Japanese attrition per month, which may be possible with tactics and technology advancements you depict.
 
Well, the US submarine navy in its height of operations in 1944 was able to inflict something like 10% attrition to Japanese per month, with most critically intercepting and decoding Japanese ratio. You, on other hand, aim for something like 40% per month, with much smaller and less capable submarine fleet and without broken radio codes. This is called "wishful thinking" or "wank".
To be realistic, try to keep fighting with 3% Japanese attrition per month, which may be possible with tactics and technology advancements you depict.

Please read my articles. before commenting and please read about the technological achievements of previous generations.
The aim is not merchant convoys on large oceans like the Atlantic or the Pacific, but armed transports in sea straits similar in size of the North Sea, who were attacked by a group of 3 to 4 boats in close proximity of each other with radio communication prior to the final attack.
The tactic is an evolution from a group of submarines, division, waiting in ambush for passing armed convoy with an invasion force to a active hunting tactic, using first surface vessels and later airplanes and the submarines own hydrophones.
Again O-16 damaged/sunk 6 ships K-XIV sunk 4 ships in one attack on their own, not in a division. The divison-roedel tactic or "wolfpack" was practiced for nearly 20 years.
 
I would add that while far more experianced, the German Uboats did manage to frequently pull of some devestating attacks on some WW2 convoys escorted by the then most experianced ASW experts in the world in the middle of the Atlantic.

Here we have some very good boats who ITTL have been training for this confrontation for 2 decades (as per the OPs POD) - operating in a littoral environment where the enemy is constrained by geography meaning that a Dutch Wolf Pack does not have to manouvre anything like the Uboats did in the Atlanitic and the Dutch Sub line is almost guaranteed to be 'run over' by the IJN convoy allowing it to get in some good multiple attacks verses the Transports beign escorted by a Navy which generally was very poor at ASW.
 
Here the Dutch are working in a target rich environment and can fire spreads across a convoy so that a miss on one ship may well strike a consort. I believe the expression is 'shooting fish in a barrel' If you can get you 'pack' of subs in the right position in congested waters then a convoy can be hurt very badly.
 

trurle

Banned
Please read my articles. before commenting and please read about the technological achievements of previous generations.
The aim is not merchant convoys on large oceans like the Atlantic or the Pacific, but armed transports in sea straits similar in size of the North Sea, who were attacked by a group of 3 to 4 boats in close proximity of each other with radio communication prior to the final attack.
The tactic is an evolution from a group of submarines, division, waiting in ambush for passing armed convoy with an invasion force to a active hunting tactic, using first surface vessels and later airplanes and the submarines own hydrophones.
Again O-16 damaged/sunk 6 ships K-XIV sunk 4 ships in one attack on their own, not in a division. The divison-roedel tactic or "wolfpack" was practiced for nearly 20 years.
OTL O-16 attacking in harbor 12 December 1941, at point-blank range and against stationary targets, records 3 sunk and 1 damaged transport, not 6 sunk. Also, all of "sunk" ships were eventually repaired by Japanese, due shallow sinking depth. I should also note the O-16 was destroyed while returning from that mission.

K-XIV in her attack 23 December 1941 actually sunk 1-2 and damaged 2-3 Japanese transports (again, at least part of them stationary unloading troops), not sunk all four. Later in war she was able to score only 4 10-ton boats.
http://www.dutchsubmarines.com/boats/boat_o16.htm
http://www.dutchsubmarines.com/boats/boat_kxiv.htm
Boats above highlights the main problem: Dutch submarines were too slow to effectively intercept anything moving.


Overall, you tend to bias data to the advantage of Dutch. Hope this is not intentional.

Here the Dutch are working in a target rich environment and can fire spreads across a convoy so that a miss on one ship may well strike a consort. I believe the expression is 'shooting fish in a barrel' If you can get you 'pack' of subs in the right position in congested waters then a convoy can be hurt very badly.
In real world, dense Japanese convoys were appearing only by 1943, to offer mutual protection against air attacks. Even "dense" convoys have spacing of several ship lengths, to prevent collisions and give way for anti-torpedo maneuvering. In 1942, the Japanese transport ships in convoys were typically separated by 1-2 kilometers distance, therefore accidental hits are not a factor. Sometimes, Japanese escorts were deliberately taking hits to shield the much larger transports though.
 
Last edited:

trurle

Banned
operating in a littoral environment where the enemy is constrained by geography meaning that a Dutch Wolf Pack does not have to manouvre anything like the Uboats did in the Atlanitic and the Dutch Sub line is almost guaranteed to be 'run over' by the IJN convoy allowing it to get in some good multiple attacks verses the Transports
Singapore to Borneo strait is roughly 400km wide. IOTL, German submarines were unable to completely block even English Channel (which is in average only half wide, and below 30km in one point). This partially due short intercept range of submarines, and partially because of minelayers constraining submarine operations (and Japanese did not forget to mine approaches to waters where ambushes are more likely - O-16 has succumbed to mine of that sort).
More or less effective (not yet absolute) blockade in WWII was in Gulf of Finland, which have roughly 50km wide and long throat. This is "bleeding edge" achievement with the technology of 1941, and it was achieved more with minefields rather than submarines.

Good luck with impossible task of blocking 400km wide strait with 12-25 km/h submarines.:extremelyhappy: (oh, other straits around Borneo too!)
 
Last edited:
Singapore to Borneo strait is roughly 400km wide. IOTL, German submarines were unable to completely block even English Channel (which is in average only half wide, and below 30km in places). This partially due short intercept range of submarines, and partially because of minelayers constraining submarine operations (and Japanese did not forget to mine approaches to waters where ambushes are more likely). Good luck with impossible task.:extremelyhappy:
Agree in part but the main reason U-boats did not operate in the channel was the minor point of it being the RN's anti submarine training area and next to a couple of the RN's biggest bases. So an environment full of ASW ships/planes which knew its quirks backwards, pretty much the most hostile place in WW2 for a U-boat. In comparison the Singapore/Borneo strait is empty.
Mine laying takes time, when these attacks are meant to take place , the Japanese would not had the opportunity to lay big fields yet ( they cannot start major operations till the Philippines has fallen ). They are also a double edged weapon, they make guessing where convoys will go easier and divert resources to their maintenance. They would be something put in place more after the DEI has fallen rather than during an attempted invasion.
 
Singapore to Borneo strait is roughly 400km wide. IOTL, German submarines were unable to completely block even English Channel (which is in average only half wide, and below 30km in one point). This partially due short intercept range of submarines, and partially because of minelayers constraining submarine operations (and Japanese did not forget to mine approaches to waters where ambushes are more likely - O-16 has succumbed to mine of that sort).
More or less effective (not yet absolute) blockade in WWII was in Gulf of Finland, which have roughly 50km wide and long throat. This is "bleeding edge" achievement with the technology of 1941, and it was achieved more with minefields rather than submarines.

Good luck with impossible task of blocking 400km wide strait with 12-25 km/h submarines.:extremelyhappy: (oh, other straits around Borneo too!)
What? No. The English Channel was very heavily mined and heavily patrolled and was effectively controlled by the British. It is also shallow and has very fast currents. It’s death to a Uboat. The Dutch boats themselves are not the principle method of detecting a given Japanese convoy. That would be MPAs and possibly a looser patrol line of Subs. The Subs of the Wolf pack would manoeuvre into position on the surface and submerge ahead of the convoy in an extended patrol line like a mobile mine field. Allowing some of the boats to attack as per wolf pack tactics in the Atlantic as the convoy crosses a portion of the line. I would add that the Atlantic is significantly larger than the English Channel and yet the Uboats repeatedly pulled this tactic off against very determined and skilled opponents.
 
Top