Correct - only 2,000 km, not 2,400 km. That would allow her to run surfaced by day for an additional 100 km, and shave 8 hours off the voyage time. That doesn't seem like a significant difference.
Into the Fire - the "Minor" nations of WW2 strike back
- Thread starter Wings
- Start date
What was S
Scarouff's max underwater range? Would she have to overnight in a bay in the Phililpines, before making the runto Bataan?
130 km. But she could run for over 15 hours on battery. And provided there were no nearby searchers, she could surface by night, so she would not need to use her whole underwater endurance.
She wouldn't overnight: that's when she could run surfaced.
Most likely, Surcouf would run surfaced by night to about 100 km from Bataan, submerge just before dawn, close to 2-3 km, then surface after sunset for the final run. Laying up anywhere would extend the trip time. Of course laying up would probably be necessary, also dives at night when Japanese patrols were encountered, and the trips would be more like 20 days per round trip.
Problem is that the MGB-501 design was only delivered to the British around Summer of 1942 IIRC. Time to build them in the shipyard and prove they work and you're looking at an entry in service in late '42. Now for the Americans, time to get the designs, get the shipyards and then get them delivered and you're looking at an entry in service in 1943, which by then will be too late to matter. It's actually better for the USN to order the submarines which can be laid down as early as April and ready for service as soon as October (even before the MGBs).
I calculated and Surcouf would be able to do the Singapore-Bataan route in 3 days fully surfaced and 6 days fully submerged. Considering that the run around Malaya can be done surfaced, it's not improbable for it to be able to do 4 or 5 day rotations in positive weather conditions, hence 3 to 6 days. Overall, most of the cruiser submarines will take a week for these rotations, and can carry 2-3 days of rations' worth each. Add to that the submarines of Asiatic fleet, which would carry each around a day of rations, and you can hold on until the next subs and the MGBs come around October, date at which the situation will become bearable.
Surcouf's submerged range was about 70 nautical miles, that's less than 8 hours of travel it its speed. It can not run an entire 12 hour day submerged, and presumably cannot snorkel like late-war uboats.
That's true, it is an optimistic estimate. I'll correct the 3 supply runs in February to operate from Miri since Borneo was still unoccupied and the RN could still supply Brunei Bay somewhat with their air cover over the area.
I seem to have misread the specs on Surcouf and used the wrong numbers. Oops. I'll try again.
Singapore-Bataan is 2,400 km. Surcouf's top speed was 34 km/hr. 2,400/34 ~= 71 hours, so, yes, in theory, Surcouf could make the trip in three days. But running surfaced by day would be very risky. Running submerged, Surcouf could make 19 km/hr for. a short spurt, or 9 km/hr for about 12 hours. Running submerged by day and surface by night, she would average about 22 km/hr, for a passage time of about 109 hours - 4 1/2 days. Allowing one day at each end for loading, unloading, refueling, and so forth, that means one round trip every 11 days. Two days rations delivered every 11 days would not be enough.
Yes, she could. She cannot run at top underwater speed (19 km/hr) for 12 hours straight (I suppose), but she could run 130 km at 8 km/hr, which would be over 16 hours. Most WW II submarines could stay down for over 24 hours. A few even approached 48 hours while evading attack, though much of that time would be spent sitting on the bottom or running dead slow.
Last edited:
No, but it wouldn't be alone. This was still at a point (February) where Bataan had adequate supplies, and was also helped by the Asiatic Fleet. With the addition of more Allied submarines, and with the "Three Musketeer" group, you're going to be averaging one "big" delivery per week (with around 3 days worth of rations), and several deliveries during that same week (each around a day's worth or less).
So, sure, alone, the Surcouf isn't enough. But it is part of a bigger effort.
The Allies produced and forward deployed chemical munitions as a WW II version of MAD. If Axis uses chemical weapons we can quickly reply in kind.
An interesting story arc for the Philippines would be a 'Pedestal / Santa Maria' convoy style effort to resupply the allied forces and population etc
Perhaps a realisation that small vessels and submarines alone cannot cut it resulting in maximum effort heavily escorted convoy
Perhaps a realisation that small vessels and submarines alone cannot cut it resulting in maximum effort heavily escorted convoy
Yes the majority of 'distance travelled' would be while surfaced.
Very little distance would be made underwater due to battery usage
A submarine in WW2 would generally operate on the surface for much of its patrol/journey only diving when stealth was an issue - however I keep cycling back to the Surcoufs very slow diving time of 2 minutes to get to 12 meters below the surface (rendering it very hard to spot from the air) and also I am not sure what doctrine the French Navy used at the time.
So its likely that we are likely doubling the number of days it would take to get there from Singapore - unload and get back and reload.
And this does not take into account any TLC required between trips.
So now that has been thrashed out I think your assessment of only 2 trips max per month is more likely to be correct unless a more riskier approach was taken
The USN for example had a pre war doctrine that persisted into 1942 of staying submerged during the day greatly reducing speed and visibility distance and only surfacing at night which was abandoned in the face of the need to improve the efficiency of the USN submarine fleet (and the frustration of their commanders who chafed under such restrictions).
TBF, three trips/month. Still hopelessly inadequate. At about this time OTL, 100,000 Germans were cut off in the Demyansk pocket for 10 weeks. They held until relieved with 350 tons/day of supplies delivered by air. Bataan would have about the same number. Maybe fewer troops, but a lot more civilians including Filipino residents of the area.
If the mission is to find and destroy the enemy, the riskier approach of running surfaced except when engaged is justifiable. If the mission is to pass safely through enemy-patrolled waters, maximum stealth would be appropriate.
Yes the more I think on this the answer would be several fold
Better use of the existing supplies - OTL entire supply dumps where destroyed or abandoned despite the transport being available to move a large amount of it
Perhaps an air bridge could be conducted as well as the limited 'Submarine Bridge'?
But ultimately it might require a major 'fast convoy' effort to deliver many 1000s of tons of supplies and this would probably be as hotly contested as the Pedestal Malta convoy and require a major effort from the allied navies - possibly in conjunction with other operations to divert the IJN and IJA air forces.
The logistics for convoys of that type to supply 100k people, are virtually impossible. Everything for the U.S. fleet operations for the Asiatic and Pacific Fleets would gave to be directed there.
You have hundreds of thousands of Allied civilians in Normandy . You do not murder your allies civilians by the thousands and expect them to welcome yo
Here is a link to American production of Chemical weapons in WW II. https://www.denix.osd.mil/rcwmprogram/history/"Because sulfur mustard vapor is heavier than air, it will sink to low-lying areas, increasing the risk of exposure there. Avoid low-lying areas. Sulfur mustard can last 1–2 days in the environment in average weather conditions and weeks to months in very cold conditions."
Sulfur Mustard (Mustard Gas): Exposure, Decontamination, Treatment | Chemical Emergencies | CDC
Learn basic facts about Sulfur Mustard (Mustard Gas) exposure, decontamination, and treatment.www.cdc.gov
The allies didn't have nerve gas but mustard is a very disagreeable thing
Since this AH began it's involvement with the United States in the Far East, it has entered, IMO, a fantasy or ASB level. the author has by author's fiat without any POD, changed the personalities of General Douglas MacArthur and Admiral Thomas Hart, Changed War Plan Orange , had American Naval forces violating USN policies and prior to the outbreak of the war operating with Allied forces, a production capacity of Army and Navy aircraft and heavy weapons, that would not be achieved OTL until 1943, to say nothing of the Philippine army being at almost U.S. Army training levels.
It would have also denied the French farmers in the area, many of which could not evacuate, their farm horses and livestock, leading to famine..