HJ Tulp
Donor
It might be an idea to look at the Italian actions against RN subs in the Med, as an idea what might have happened?
Not dissimilar; lots of shallow water, subs operating inshore a lot, 2nd rate (but not negligible) A/S force, aggressive sub skippers. Although the IJN wouldn't have the advantage of air cover.
Hmmm good idea. Do you know if the Italians used heavily protected, large convoys or smaller ones?
Riain said:The IJN won't have to sink an Oboat, merely attack it and force it down while the convoy zags away out of range of the much slower Oboat with its very short range weapons. The real havoc with subs comes from pack tactics, the Uboats were famous for it and the USN worked in smaller packs of about 3 boats where the convoy would be boxed in and subject to multiple torpedo salvos from multiple boats. If you can vector multiple subs in on an invasion convoy then you stand a good change of sinking multiple ships and doing some serious damage, but a single boat will only get one or maybe two salvos off before the counter-attack and the convoy going out of range. One or two salvos isn't going to stop an invasion convoy and gathering enough subs onto a target will be difficult.
I agree with you. Luckily so did the Royal Netherlands Navy! The submarine arm was able to operate in divisions of 5 boats each. According to the source I mentioned in the OP they were also able to spot a enemy flotilla, steal a march on it during the night and then wait for them for an ambush. I'm a bit sceptical about the last claim though the speed of the Dutch submarines (roughly 18 knots) should be fast enough in theory.
What I am really curious about is the SOP of a japanese invasion fleet when attacked from beneath the water by multiple submarines. I assume that the destroyers will try to find and destroy or at least supress the submarines. How many destroyers though? And I assume the invasion fleet itself will keep steaming ahead as fast as possible. That means that part of the escort will be very much out of position if a second division or the ABDA-fleet makes a move.