RN submarines in the Pacific.

Pre-war the RN had something like 21 O, P & R class submarines designed for Pacific conditions stationed in the Far East. They also had 3 River class subs which were supposed to be for fleet ops, they resembled many of the large subs in use with the IJN and USN. These boats did have some problems, and when war broke out in 1939 they were redeployed to the Med and home waters where their problems were magnified and size played against them and many were sunk.

WI they were not redeployed, only sent to Singapore where they were stationed on Dec 8th, 1941. Would the RN subs shadow the invading Japanese transports, and would they get the order to attack when operation Matador was given the green light? Would 2 dozen subs in the target rich environment of the Sth China Sea make much of a difference?
 

Redbeard

Banned
The British plans in case of war with Japan indeed did involve a trade war with subs, surface and air vessels to cut off Japan from imports. But not at least Churchill insisted on Singapore/the far east being drained of assets for the benefit of various Mediterranean dreams and schemes - "something could always be sent" was Churchill's opinion, if troubles should arise in the far east.

Had Singapore been given the forces she was planned to have, and as CIGS proposed in 1941, then I agree with the previos poster that Japan's position would have been extremely difficult and that they probably would have had to abandon any attack plans on SEA.

Had they had any strategic manoeuvreability, and foresight, they would have offered the British an alliance in 1941. But, seen on the bacground of stunning German successes vs. France in 40 and apparantly even more so against USSR in mid 41, I guess that would be too much to ask from a Japan run by garrison bigots.

Regards

Steffen Redbeard
 
RN Submarines in the Pacific

There actually were RN submarines in the area at the start of the war and they were deployed as a deterrent and actually exercised in the Inland Sea. This isn't hidden history but is mentioned in a books by Alistair Mars who served in the area but they were redeployed to the Mediterranean.

Would they have had an effect if they had remained? Possibly. American submarines mounted an effective blockade of Japan cutting of the supply lines like the U-boats tried with Britain only unlike the Royal Navy, the IJN's anti submarine tactics were not well developed as defensive warfare did not have high priority and Japan was still living in the era of Mahon. The IJN regarded damage control as defeatist and lost the Shinano and Kongo to submarines and several ships at the start of both the Phillipne Sea and Leyte Gulf. I suspect they would have gone ahead anyway although the Royal Navy would have exacted a toll.

An interesting question to ask would be what if the Royal Navy had a submrine or two off the Falklands in 1982 as they did in 1977. Would the invasion have been called off?
 
There were a large number of invasions very close to Singapore during the first 3 months of the war, this would give the RN a chance to disrupt the Japanese campaigns, which were often mounted on a shoestring. Also these convoys were heavily gaurded, several of the naval battles in the NEI in the first months of the war were over invasion convoys, so this would give the RN a chance to attack important and irreplaceable ships like cruisers.
 
I've scrounged from scattered sources that the IJN was quite good at ASW in dribs and drabs, in particular they designed a very nice DE in the late 30s which would have been great as a convoy escort. But like so much else in militarist Japan it wasn't pursued with any sort of logical strategy or priority. They were too tied up with their own plans to give it any thought anyway.

This is why I think a possible RN sub fleet from Singapore would have a good window of opportunity to wreak havoc on the IJN and it's operations, especially considering RN torps work and its crews are experienced.
 
I'd stop to consider the nature of the target. These aren't typical merchant convoys, which were small & thinly escorted. These were heavily-escorted landing forces, which by their nature are harder targets, even given lousy overall IJN ASW. There's better chance of a sub being spotted, they're probably moving faster (harder to catch, track, & approach to shoot), & with more escorts, harder to get away from afterward.:eek:

Also, where were the subs deployed? Hart's deployments around the obvious LZ in P.I., Lingayen Gulf, were bungled. (He had enough S-boats with working torpedoes to make a dent in the IJA force.) Were RN deployments off Malaya any good?

Having said that, 21 boats, deployed well & operated aggressively, could have had a significant impact on Japanese plans. Recall, IJA was on a knife edge: the slightest disruption anywhere would've had knock-on effects well downstream. Delay in Malaya could've delayed or cancelled MO, which could've made MacArthur's ops in Papua:p easier & Watchtower more/less a cakewalk. Or it could've provoked Yamamoto to try MI earlier....
 
Who knows how it'd have played out, but the RN submarines had been stationed out East since the 1920s so knew the waters well, and had been on a war footing, more or less, since 1939. And the disadvantages they faced in the confined Med would've been mitigated in the Pacific.


I think the knowledge that several flotillas of RN submarines, in addition to the Dutch and US ones, would've severely worried anyone planning an extended amphibious campaign, especially against the Malay Peninsula where they'd face superior forces that could become bogged down and require reinforcement.
 
I think this might be one of things that in conjunction with other changes could bear fruit. A sub sighting of the convoy heading for Khota Baru could trigger Op Matador, and assist Force Z in achieving something before being sunk. But if Singapore falls as quickly as IOTL there isn't going to be much scope for a sub campaign to rack up a long list of sinkings.
 
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