Wow. Two GS on any kind of fixed defences would ruin anyone's day.
"I'm sure there was a bunker complex here somewhere."
WI: 'Tall Boys' & 'Grand Slams' used by the US against & Japan?
- Thread starter Giant Man Eating Rabbits
- Start date
"I'm sure there was a bunker complex here somewhere."
A lot of the missions were flown relatively low (15,000ft) for accuracy.
The Sorpe Dam was also attacked with Tallboys (by 9 Squadron conventionally from 14,000ft) on 15th October 1944 and hit by 2 Tallboys but not breached (one Tallboy was found in the mud when the dam was partially drained in 1958 and successfully defused*
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Tallboys could have been used, but Grand Slams? Not even the B-29 could carry them to Japan until Okinawa is secured and the airfield repaired and expanded for B-29s, something that only happened in August 1945.
The US bombing campaign off mainland Japan primarily operated from bases in the Marianas: Saipan, Guam, and Tinian mostly. Some airfields in China were also available for use, about the same distance from Japan proper as the Marianas bases. Those are about 2500 km from cities like Tokyo and Kyoto. The B-29 can operate in a 2600 km radius with a 12,000lb payload at medium altitude, so Tallboys can be delivered to mainland Japan and Okinawa, but the Grand Slam is nearly twice as heavy, and a reduced version of the rocket equation means that the operational range with 1 Grand Slam would thus be significantly less than half that of the B-29, which may not even be enough to reach Iwo Jima from Saipan (~1150 km).
How effective would the Tallboys be though? On Iwo Jima and Okinawa, the issue is targeting. Cave systems are very hard to identify from the air, and not even ground units can identify major cave locations without having cleared them out in the first place. Plus, from my (limited) understanding of geology, the igneous rock typical of Iwo Jima and Okinawa (due to their volcanic origins), is much more resistant to shockwaves than other materials, limiting the effect of the craters and shockwaves.
On Japan proper, there aren't that many targets worth hitting with a Tallboy/Grand Slam. Whereas the Tirpitz could threaten Arctic convoys, Yamato had no fuel left except for a one-way mission and was not placed to interdict any supply lines, and US naval dominance after Leyte Gulf could easily deal with 1 battleship (as Okinawa demonstrated).
Japan had no wunderwaffen sites able to strike the US (well, maybe I-400s with bioweapons, but I don't believe the US was aware of operation PX during the war), and their submarine fleet was rendered ineffective bar a few attacks of opportunity between the increasing amount of destroyers and fuel shortages. The Japanese pens were also nowhere near as fortified as their German counterparts.
Japanese industry was very decentralized, so there aren't many big industrial complexes to target (another reason why the US switched to firebombing; a larger area of effect would destroyer more workshops).
Command bunkers would be invisible from the air and thus hard to target, as well as being heavily defended by concentrated AA units (who would also have an easier time targeting lower altitude bombers). The only really viable target is railway tunnels, which may have some effect, but the US submarine campaign was already doing a good job crippling intercity trade.
All in all, they have no substantial impact on the war. Maybe Kanmon gets blown up and has to be rebuilt in the postwar and a few extra craters exist in Japan, Iwo Jima, and Okinawa, but the war still ends on the same date with mostly the same amount of casualties.
The US bombing campaign off mainland Japan primarily operated from bases in the Marianas: Saipan, Guam, and Tinian mostly. Some airfields in China were also available for use, about the same distance from Japan proper as the Marianas bases. Those are about 2500 km from cities like Tokyo and Kyoto. The B-29 can operate in a 2600 km radius with a 12,000lb payload at medium altitude, so Tallboys can be delivered to mainland Japan and Okinawa, but the Grand Slam is nearly twice as heavy, and a reduced version of the rocket equation means that the operational range with 1 Grand Slam would thus be significantly less than half that of the B-29, which may not even be enough to reach Iwo Jima from Saipan (~1150 km).
How effective would the Tallboys be though? On Iwo Jima and Okinawa, the issue is targeting. Cave systems are very hard to identify from the air, and not even ground units can identify major cave locations without having cleared them out in the first place. Plus, from my (limited) understanding of geology, the igneous rock typical of Iwo Jima and Okinawa (due to their volcanic origins), is much more resistant to shockwaves than other materials, limiting the effect of the craters and shockwaves.
On Japan proper, there aren't that many targets worth hitting with a Tallboy/Grand Slam. Whereas the Tirpitz could threaten Arctic convoys, Yamato had no fuel left except for a one-way mission and was not placed to interdict any supply lines, and US naval dominance after Leyte Gulf could easily deal with 1 battleship (as Okinawa demonstrated).
Japan had no wunderwaffen sites able to strike the US (well, maybe I-400s with bioweapons, but I don't believe the US was aware of operation PX during the war), and their submarine fleet was rendered ineffective bar a few attacks of opportunity between the increasing amount of destroyers and fuel shortages. The Japanese pens were also nowhere near as fortified as their German counterparts.
Japanese industry was very decentralized, so there aren't many big industrial complexes to target (another reason why the US switched to firebombing; a larger area of effect would destroyer more workshops).
Command bunkers would be invisible from the air and thus hard to target, as well as being heavily defended by concentrated AA units (who would also have an easier time targeting lower altitude bombers). The only really viable target is railway tunnels, which may have some effect, but the US submarine campaign was already doing a good job crippling intercity trade.
All in all, they have no substantial impact on the war. Maybe Kanmon gets blown up and has to be rebuilt in the postwar and a few extra craters exist in Japan, Iwo Jima, and Okinawa, but the war still ends on the same date with mostly the same amount of casualties.
Others have already why bother what with the submarine offensive, conventional bombing campaign and both nukes as well as the Russian declaration of war - so I will look at what type of targets
That's a fairly easy question to answer as it would be the same targets as those in the ETO
But these would only be worth it if the Allies had gone ahead with the 'Full' invasion of Japan - otherwise little point.
That's a fairly easy question to answer as it would be the same targets as those in the ETO
- Capital ships (Tirpitz)and bases for littoral fleets such as the attacks on Le Harve where tall boys where dropped into the harbour to destroy scores of e-boats and chariot type craft after D-Day.
- Major Bridges, Viaducts and Tunnels
- Hardened submarine Pens (where there any in Japan?)
- Critical Factories - the bombs where originally designed on the concept that machine tools needed hardened floors which normal bombing did very little too and machine tools were difficult to destroy and so a bombed factory could be put back into operation relatively quickly despite the damage to the buildings and the Tall boys would using the earth quake effects would damage the flooring as well making it much harder to bring a given factory back into operation.
- Hardened command centres - again not sure if there was such a target?
But these would only be worth it if the Allies had gone ahead with the 'Full' invasion of Japan - otherwise little point.
Tbh I can't think of any military target in Japan that would needed these beasts, short of maybe some HQ bunker I'm unfamiliar with, so let's go for civilian targets: aqueducts, rail/road viaducts and tunnels. These bombs were used on those too. So what targets like this exist in Japan, important enough to be targeted in such way?
The bombing campaign for the home Islands started the Summer of '44, and took off in Feb. '45 and lasted until the end of the war 6 months later.
The US did not start development on the T-10 (US version of Tallboy) until late '44. Which explains why it never made it into WWII. Halsey's attack on Kure happened in July 45. Would B-29s modified to carry these bombs have been available by then.
Certainly not going to modify the Silverplate B-29s for this, The 509th was already dropping Pumpkin Bombs "Practice Nukes" loaded with 6000+ pounds of HE on Japanese targets. So from the Raids on Kure that destroyed what was left of the Japanese navy at the end of July '45 until the end of the war it was a 3 week timeframe.
Just no room for tallboys, nor a need at this point.
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I am questioning even these. Roving aircraft were routinely shooting up the rolling stock enough to paralyze system without dropping the infrastructure.
True but, for example, the RAF Tallboyed 2 railway tunnels (Saumur and Rilly La Montagne). No more traffic from those. The Saumur raid, in June 44, caused massive delays of german reinforcements to Normandy, including a panzer div. That's one raid at altitude, against one single target, vs dozens of raids of planes at low altitude, having to find something to shoot up.
I've always wondered about the potential viability of say 14 inch or 16 inch BB shells being modified Tiny Tim Style with powerful rocket motors. Something like a semi AP bomb with a reinforced nose.
Just think "Fritz X". Don't think you need the rocket, tbh. HMS Warspite was almost sunk by one Fritz X, which penetrated almost all the ship; another blew up close enough to damage it more. The battleship Roma took 2 hits and blew up...
Nazi incompetence? 😝Spoke like a Brit ... Just remember who saved your royal keasters.
took you long enough to pick a side ;-)Spoke like a Brit ... Just remember who saved your royal keasters.
I am, of course, being factious. The Lancaster or Lincoln wouldn't really be suitable for the distances involved in the pacific without refuelling and without USAAF logistics and basing support which would be only grudgingly offered ( see British Pacific fleet)
The answer would have been modified B29's, IF suitable targets really existed in Japan.
Giant Man Eating Rabbits
Banned
I think the RAF's Tiger Force would disagree.
They were well involved in trying out air-to-air refueling and were nearly picked to drop the atomic bombs on Japan until the above mentioned converted B-29's were converted.
agreed - however that technology was VERY cutting edge & still doesn't reduce the requirement for USSAF support in basing and logistics which I think would only be very grudgingly offer.
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...woooow...
Yeah, I can see these being used in Japan. They are much lighter and smaller than Tall & Grand. Anyone has the dimensions of the B-29's bomb bay? I'd love to know if it could carry one (or more?) internally. That would give it at least a payload of 3 (wing, wing, bay) while saving a lot of weight, so no loss of range/performance other than that caused by drag of the bomsb.