What if Japan attack both Pearl Habor and Panama canal at the same time

[tchizek]

Also even before the war started both ends of the Canal were heavily patrolled both by aircraft and ships. The US was well aware of the choke-point that the canal presented a potential adversary. There were several Destroyer squadrons and Patrol aircraft squadrons assigned to both ends of the canal. Any unidentified sub or ship would approaching would be investigated. It would be possible but difficult to get a sub close enough to actually mine the approaches even if you get Japan to break their doctrine to try it and break enough logistics loose from their already tight logistical schedule for what is basically a pointless exercise since the number of subs that they could send that distance would not make any difference at all in the Americans ability to use the canal. The US was already upgrading the defenses prior to the start of the war so attacking will not change the amount of force the US puts there. The US already had several patrol wings and fighter wings stationed there so it will not change the number of aircraft stationed there. The US already had a heavy naval presence, it might add to the number of destroyers assigned, or maybe not because the US was already scheduled to add two more squadrons of DD/DEs to each end of the Canal during the first part of the war anyway. So the Japanese spend fuel they can't afford, probably loose one or more subs they can't afford, maybe sink one or two ships if they get lucky and don't really impact what the US does at all.

Basically a pointless exercise for the Japanese - even more so than what they did iOTL.

 

[CalBear]

One issue that has not been brought up is that this tends to become an either or game. You either attack Pearl with total surprise OR you attack the Canal with total surprise. The timing is such that you don't get both. The Canal Zone and Pearl were both on War Warning. Once one is is positively hit the other is going to go to full war footing. Neither position is under the command of MacArthur so the utterly bewildering lack of action that marked the first day of the war in the Philippines is not going to happen.

The Canal Zone was on a war footing beyond even that of Hawaii due to the U-boat threat. A nightmare scenario involving submarine attack was already part of the Canal defensive planning. Each side of the Canal had a destroyer division assigned, there were two fighter groups (granted one equipped with P-26, but that is still an overmatch for a sub launched floatplane) two PBY patrol groups totaling 25 aircraft and fairly substantial U.S. Army artillery presence up to and including 14" railroad guns. A rather tough nut to crack.

Ninja'd!

 

[tchizek]

If by planes you use torpedoes on the lock gates. If a hole is blow in all the lock doors, then the lake drains, and their is likely major erosion damage. With some luck, maybe the canal is closed for months. But the only plan required a special built submarine that did not exist at the start of the war, and requires a POD a few years before the war to build.

Agreed, the sabotage is more likely. Many a commando team landed by submarine or false flag ships could make a penetration, take over some portion, and damage it. Something a simple as scuttling a couple of ships at the right point. Or maybe taking over the gate house, opening the gates, then jamming them open might have a shot. Based on how prepared Pearl was that day, I wonder how prepared the guards around the canal were that day.

The problem with the torpedo idea is that the locks are huge and very strong an aerial torpedo will basically bounce off - think several feet of steel. These are not ships, even war ships these are meant to hold back hundreds of tons of water plus ship.

The US was VERY careful of false flag ships, boarding every ship and turning back about 10% after 1939. Refusing to allow any questionable ships, confiscating anything that could be used for taking pictures or film, let alone weapons. The idea of allowing anything that looked anything like a commando team anywhere near the Canal is not going to happen.

Also what would the commando team do if they got there - this is a huge thing, there isn't a single choke point for them to go after. There isn't a single control room or a single easy to blow up point that will disable the whole thing. There are two parallel set of locks that are massive and mechanical, small amounts of explosive are going to do very little to them unless you get very close to very precise points which by the way are protected by two divisions of troops.

 

[elkarlo]

Attack the canal? With what? Camera-wielding tourists?

Just reaching Hawaii was at the outer limits of their logistical capabilities.

Send in a merchant ship. One with a reenforced hull. Sink it on Dec 7th somewhere in the canal. That, or send a SF unit to seize a ship or 3, and sink them in the canal. Doesn't have to be a conventional attack.

 

[elkarlo]

The problem with the torpedo idea is that the locks are huge and very strong an aerial torpedo will basically bounce off - think several feet of steel. These are not ships, even war ships these are meant to hold back hundreds of tons of water plus ship.

The US was VERY careful of false flag ships, boarding every ship and turning back about 10% after 1939. Refusing to allow any questionable ships, confiscating anything that could be used for taking pictures or film, let alone weapons. The idea of allowing anything that looked anything like a commando team anywhere near the Canal is not going to happen.

Also what would the commando team do if they got there - this is a huge thing, there isn't a single choke point for them to go after. There isn't a single control room or a single easy to blow up point that will disable the whole thing. There are two parallel set of locks that are massive and mechanical, small amounts of explosive are going to do very little to them unless you get very close to very precise points which by the way are protected by two divisions of troops.

Crap, beat me to it. What if SF teams seized a ship and sank it? Even a week delay is quite a bit of damage.

 

[tchizek]

Send in a merchant ship. One with a reenforced hull. Sink it on Dec 7th somewhere in the canal. That, or send a SF unit to seize a ship or 3, and sink them in the canal. Doesn't have to be a conventional attack.

If they are searching carefully enough to find cameras (and they were) then they are searching carefully enough to find an SF unit and arrest them before they can seize a ship let alone more then one. The US was very, very careful of who they let into the canal after 1939. It is also harder than you think might think to both sink a ship in the right place and keep it there for any length of time. The US had clearing teams that could potentially clear a blockage in 1-3 days (estimated). Which would not stop the canal at all since there are two sets of locks.

 

[mowque]

What exactly could an air raid do to the Canal anyway? Thing is made of super thick concrete and massive amounts of steel, and we'd fix it in a hurry anyway....

 

[Snowman23]

Yeah i thought of that too (i said use the subs to deploy mines in my post).

Read a bit too fast, sorry.

The Japanese submarines built to carry seaplanes where not commissioned until 1944/1945 genius.

Not true at all. By 1941 the IJN had at least 10 submarines that could carry a single seaplane, the B-1, B-2, and B-3's. In fact, in 1942 the Japanese tried to use one of the seaplanes to cause a forest fire in the Pacific Northwest by sneaking to the West Coast and launching it right off the shore. Obviously, it didn't work.

 

[elkarlo]

If they are searching carefully enough to find cameras (and they were) then they are searching carefully enough to find an SF unit and arrest them before they can seize a ship let alone more then one. The US was very, very careful of who they let into the canal after 1939. It is also harder than you think might think to both sink a ship in the right place and keep it there for any length of time. The US had clearing teams that could potentially clear a blockage in 1-3 days (estimated). Which would not stop the canal at all since there are two sets of locks.

They don't need to even land near the canal zone. The unit can be put ashore, and then travel through the interior to an area near the canal zone. They could steal a small boat, and board a merchant vessel, and with a small charge, sink it. Think Black Tom.

Didn't think the response would be that quick. That's interesting.

 

[Mike Stearns]

What about putting something in the bottom of the Canal that tears open the hull of a passing ship?

Refloating the ship in question might only take a day or two, but you'd have to shut down all traffic on the Canal an extended period of time to perform a thorough search to ensure that nobody has left any other nasty surprises.

 

[Snowman23]

They don't need to even land near the canal zone. The unit can be put ashore, and then travel through the interior to an area near the canal zone. They could steal a small boat, and board a merchant vessel, and with a small charge, sink it. Think Black Tom.

Didn't think the response would be that quick. That's interesting.

Except any group of Japanese men sneaking their way through the Panamanian interior will draw a lot of attention, especially if armed. Don't get me wrong, it sounds like a good book of historical fiction, but it just seems unrealistic.

 

[tchizek]

They don't need to even land near the canal zone. The unit can be put ashore, and then travel through the interior to an area near the canal zone. They could steal a small boat, and board a merchant vessel, and with a small charge, sink it. Think Black Tom.

Didn't think the response would be that quick. That's interesting.

Where exactly are they going to board the merchant vessel? And what small boat are they going to steal? They US kept very close watch over everything that moved in and around the Canal.

So they land somewhere in Panama, move through the jungle avoiding all of the locals because well they look like a Japanese Special Forces Team. Carrying enough explosives to sink a large freighter quickly (because a small freighter will not do any good). They come to the edge of the canal zone and find - barbed wire and patrols. Because frankly the US doesn't trust the locals at this point. They find a weak point in the defenses and work their way past - but now they are several days past schedule. They start working their way toward Gatun Lake, which is the only real place to get a small boat and intercept a freighter. They avoid the US patrols and reach the lake to find, US PT boats patrolling and locals that all know each other and who owns what boat. They have to either find a local they can bribe (not really the Japanese style) or steal a boat and make it past the patrols on the lake, get on a freighter that has escorts on board, get rid of the escorts and pilot, successfully pilot the ship correctly through the canal to a vulnerable location without anyone noticing that the ship is being piloted by a non-canal pilot. or they have to try to keep control of the pilot and crew long enough to have them get the ship to the right spot, when all it takes is a 1 or 2 degree miss and the ship is aground in the middle of the Lake and the SF force is stranded waiting for the US Navy to show up...

This would make a great book or movie, real life would not work so well...

 

[tchizek]

What about putting something in the bottom of the Canal that tears open the hull of a passing ship?

Refloating the ship in question might only take a day or two, but you'd have to shut down all traffic on the Canal an extended period of time to perform a thorough search to ensure that nobody has left any other nasty surprises.

That would be mining the canal and it involves getting a ship or aircraft close enough to drop mines. Again the USN was very careful about who and what they let close to the Canal, getting something with naval mines actually into the canal would be shall we say difficult at best.

 

[Mike Stearns]

That would be mining the canal and it involves getting a ship or aircraft close enough to drop mines. Again the USN was very careful about who and what they let close to the Canal, getting something with naval mines actually into the canal would be shall we say difficult at best.

To be honest, I wasn't thinking of a mine at all. I was thinking of a bed of metal spikes planted in the bottom of the Canal. Everyone else is assuming that the Japanese are going to somehow be able to sneak mines or bombs past the Americans, who are obviously watching for such a thing, but they won't see metal beams as a weapon and they won't be as heavily guarded, so it shouldn't be overly difficult for a Japanese commando team to steal some, along with some welding gear and sink a bed of spikes in the Canal. Exactly how they would move them into position, I don't know, but its not what the Americans would expect and it would shut down the Canal for awhile.

 

[tchizek]

To be honest, I wasn't thinking of a mine at all. I was thinking of a bed of metal spikes planted in the bottom of the Canal. Everyone else is assuming that the Japanese are going to somehow be able to sneak mines or bombs pas the Americans, who are obviously watching for such a thing, but they won't see metal beams as a weapon and they won't as heavily guarded, so it shouldn't be overly difficult for a Japanese commando team to steal some, along with some welding gear and sink a bed of spikes in the Canal. Exactly how they would move them into position, I don't know, but its not what the Americans would expect and it would shut down the Canal for awhile.

The problem with this is the time it would take and the size of the "spikes" you would be talking tons or tens of tons of metal twenty or thirty feet long driven into the bottom of the canal, one would not do, you would need what you say a "bed" so what ten or twenty of these things? So shall we say 5 tons each (light I think but we can go with it), 30 feet long (short but we can go with it) weld up an array of these 30x30 with "spikes sticking up at the corners and the middle? So 4 sides, 2 cross bars, 4 up from the corners, 2 in the middle, 12x5 tons? 60 tons to weld and move to the canal. Or make them 1 ton each and hope they don't just bend when a 6000 ton freighter hits them? that's still 12 tons, even if they can do this , the Patrols would notice.

 

[BlondieBC]

The problem with the torpedo idea is that the locks are huge and very strong an aerial torpedo will basically bounce off - think several feet of steel. These are not ships, even war ships these are meant to hold back hundreds of tons of water plus ship.

The US was VERY careful of false flag ships, boarding every ship and turning back about 10% after 1939. Refusing to allow any questionable ships, confiscating anything that could be used for taking pictures or film, let alone weapons. The idea of allowing anything that looked anything like a commando team anywhere near the Canal is not going to happen.

Also what would the commando team do if they got there - this is a huge thing, there isn't a single choke point for them to go after. There isn't a single control room or a single easy to blow up point that will disable the whole thing. There are two parallel set of locks that are massive and mechanical, small amounts of explosive are going to do very little to them unless you get very close to very precise points which by the way are protected by two divisions of troops.

Late in the War, the Japanese thought their torpedoes would punch a hole in the lock gates. Dams were blown in Europe by single airplanes, so it seems plausible. I would expect the torpedoes to explode, not bounce. And yes the steel is thick, but how does it quality compare to say battleship steel? How many inches of non harden steel does it take to stop a 1000 or 2000 pounds of explosive force.

I agree that a commando raid is very difficult, but it might be worth the risk, after all, what, and after all the gain is so big and what is the lives of a few hundred men for the greater good of the empire. Yes, the USA is prepared for an attack, but harder attacks happened in WW2. Look at the Italian frogmen, the U-boat in Scalpa Flow. In wars, many, many dice are rolled, so even 1 in a thousand or 1 in 10,000 operations sometime work, and IMO, a commando raid probably has at least a 1% chance of causing major damage.

As to what a command team could do, simple, bypass the safety mechanisms, and open all the gates at the same time, this will turn the channel into a waterfall. Which hopefully damages the locks, cause erosion issues in the lower level channel, and lowers the lack water level so the canal can't be used until the locks are fixed and the water level in the lake refills. Or you could capture a ship and scuttle it. To me, the tough part is getting into the canal zone, then getting past the security. Once the objective is secured, the easier part is actually doing damage. Commando teams did major damage to ports in both ww1 and ww2, so it is possible. The gates only need a 10 HP motor to open, so something as simple as a stolen vehicle could open them. The gates are finely balance, like heavy doors in a well built cathedral.

And IMO, the 2 Division of troops indicates the USA new damage could be done by sabotage. There is no way 2 Divisions are needed to defend against an amphibious assault, since there is no realistic way for Japan or Germany to get that far, so to me this sounds like a lot of platoon and company size units guarding vulnerable infrastructure.

Again, it takes a prewar POD. This POD is not October 1941, lets add the canal to the war plan, someone in Japan would have need to believe in what we now call special ops, trained up men, gather intel, and probably done dress rehearsal somewhere.

 

[BlairWitch749]

what about sending a merchant ship through and having it offload some divers with limpet mines or explosive packs that can swim up to the locks and blow them

 

[BlondieBC]

One issue that has not been brought up is that this tends to become an either or game. You either attack Pearl with total surprise OR you attack the Canal with total surprise. The timing is such that you don't get both. The Canal Zone and Pearl were both on War Warning. Once one is is positively hit the other is going to go to full war footing. Neither position is under the command of MacArthur so the utterly bewildering lack of action that marked the first day of the war in the Philippines is not going to happen.

The Canal Zone was on a war footing beyond even that of Hawaii due to the U-boat threat. A nightmare scenario involving submarine attack was already part of the Canal defensive planning. Each side of the Canal had a destroyer division assigned, there were two fighter groups (granted one equipped with P-26, but that is still an overmatch for a sub launched floatplane) two PBY patrol groups totaling 25 aircraft and fairly substantial U.S. Army artillery presence up to and including 14" railroad guns. A rather tough nut to crack.

Ninja'd!

I agree that it can't be a surprise attack, because Pearl is more important. The operation would be extremely difficult, because the men would either need to land after 7:00 am Pearl (mid day Panama) or they would need to come out of hiding at this point.

I disagree on your MacArthur like performance can't be repeated. We don't know exactly what the performance would be like at the canal, but it is likely in the range of how other USA commanders reacted. So it could be as bad as Pearl, or it could be as good as wake. The most likely place would be in the middle of the pack on how USA commanders performed in the first week of the war, so likely the forces are put on alert, but there easily could be major problems with plan combined with the fog of war. So there easily could be something like the Philippine air plan, where the planes were sent up quickly, but they refueling schedule has problems and too many are on the ground when the Japanese arrive. Or like General short who saw sabotage as the main threat, not air attack. In the Canal zone, the commander could simply pick the wrong threat to focus on, and allow a window of opportunity for Japan.

Now all this said, 1-2% chance of success sounds about right to me with a POD a year before the war.

 

[BlondieBC]

Except any group of Japanese men sneaking their way through the Panamanian interior will draw a lot of attention, especially if armed. Don't get me wrong, it sounds like a good book of historical fiction, but it just seems unrealistic.

Japanese yes, but Chinese no. When the canal was built, a lot of Chinese labor was used, and some of them remained in Panama. So either ethnic Chinese recruit for the job or perhaps some Japanese that looked close enough to pass for Chinese makes it a lot easier. So one option would be for the Asian commando team to be hidden in plane site. In the entire Japanese army, I bet you can find 50 soldiers that speak Chinese without an accent and look Chinese to an American. Taiwan would be a good place to start, it seems like most of the Chinese in America are from the mainland part of China closest to Taiwan.

Or

Use mercenaries from Central or South America. I don't like this option for security reasons.

what about sending a merchant ship through and having it offload some divers with limpet mines or explosive packs that can swim up to the locks and blow them

This works great, if one can get the merchant ship with commandos in the Canal. In a strange way, on this operation, the last 100 m to the target may be the easiest part. For the limpet mine option, I would be tempted just to hire some locals, or try to have a submarine unload 10-20 Japanese divers on the Panama coast on the first day of the war.

But if I could get a merchant ship through security that was poorly searched, i would just have 30,000 lbs of explosives deep in the cargo hold that I would explode. There is no reason to get cute, if the security is that poor.

 

[tchizek]

Late in the War, the Japanese thought their torpedoes would punch a hole in the lock gates. Dams were blown in Europe by single airplanes, so it seems plausible. I would expect the torpedoes to explode, not bounce. And yes the steel is thick, but how does it quality compare to say battleship steel? How many inches of non harden steel does it take to stop a 1000 or 2000 pounds of explosive force.

Bombing dams was a fairly chancy business that didn't always work. It eventually took specialized bombs, aircraft and tactics to do it successfully. Locks are significantly tougher than battleships. There is a reason nobody used torpedoes on locks or dams in Europe either, engineering works are of a completely and totally different scale than ships, they don't have to float they don't have to (basically) move they do have to last for decades and they do have to hold back thousands of tons of water. The canal locks were hugely over-engineered by today's standards they didn't know how tough they needed to be so they multiplied everything by like 20 above what they thought they needed (which was already high) then made it tougher than that. Also Japanese air dropped torpedoes had 300-400 pounds of explosives not 1000-2000. The largest Japanese torpedo used during the war had a warhead size of 1700 pounds and that was introduced in late 1943 or early 1944 depending on which source you read.

I agree that a commando raid is very difficult, but it might be worth the risk, after all, what, and after all the gain is so big and what is the lives of a few hundred men for the greater good of the empire. Yes, the USA is prepared for an attack, but harder attacks happened in WW2. Look at the Italian frogmen, the U-boat in Scalpa Flow. In wars, many, many dice are rolled, so even 1 in a thousand or 1 in 10,000 operations sometime work, and IMO, a commando raid probably has at least a 1% chance of causing major damage.

As to what a command team could do, simple, bypass the safety mechanisms, and open all the gates at the same time, this will turn the channel into a waterfall. Which hopefully damages the locks, cause erosion issues in the lower level channel, and lowers the lack water level so the canal can't be used until the locks are fixed and the water level in the lake refills. Or you could capture a ship and scuttle it. To me, the tough part is getting into the canal zone, then getting past the security. Once the objective is secured, the easier part is actually doing damage. Commando teams did major damage to ports in both ww1 and ww2, so it is possible. The gates only need a 10 HP motor to open, so something as simple as a stolen vehicle could open them. The gates are finely balance, like heavy doors in a well built cathedral.

And IMO, the 2 Division of troops indicates the USA new damage could be done by sabotage. There is no way 2 Divisions are needed to defend against an amphibious assault, since there is no realistic way for Japan or Germany to get that far, so to me this sounds like a lot of platoon and company size units guarding vulnerable infrastructure.

Again, it takes a prewar POD. This POD is not October 1941, lets add the canal to the war plan, someone in Japan would have need to believe in what we now call special ops, trained up men, gather intel, and probably done dress rehearsal somewhere.

Yes the US believed it was possible and did defend against it. Yes it would take a POD fairly far back since there was not that level of interest in special operations of the type needed to perform this operation pre-war. Even then the odds of actually succeeding are so low as to be almost non-existent. Because the US was worried about sabotage so they defended against it.