[QUOTE=treis]
Yes, but if you’re in a hunter pack of subs vs. a convoy it’s a different story. If one ship makes a 60 degree turn away from you, that means another is making a 60 degree turn towards you. And the one that turned away from you is turning into your buddy.
[/QUOTE]
Still allows only one of the subs a shot, however, not both of them.
Both German and U.S. wolfpacks did not cooperate on a micro-tactical level. They did not setup situations (usually) were one sub would “scare” the prey into the lap of another sub, nor did they deliberately set themselves up so that subs would be a “fall back” sub in case of unexpected zigzags.
All subs would be vectored to the expected intercept locations, and left to work out their own approaches to targets past the escorts, if any.
They would share spotting info (when safe to do so), coordinate convoy intercepts (“you attack from the starboard side of the convoy, Jake and I will attack from the port side”) and, to some extent, attack times, but each submarine skipper was left to figure out his own approach past escorts, and figuring out firing solutions.
Neither the U.S. nor the German skippers were positive, to a degree of high accuracy, of where the other units of their wolfpack was at any particular moment. They would know within a few miles where a friendly boat was supposed to operate, but that is all.
Sharing “real time” spotting info with pack mates was not done with the target(s) close aboard, as, with radio firection finders on escort vessels, you are exposing your own position to them. So, there was no “Hey Guys! Look out! They just zigged to the north!” type chatter. In the German system, the “spotter” submarines or aircraft would “shadow” the convoy (from well outside torpedo or AAA range) and do blanket radio “for all hands” type broadcasts on a preset frequency.
The U.S. system was similar, in that a boat that finds itself in an unfavorable position for attack may surface outside of visual range for a contact report, and the other pack mates may pick those reports up if they are surfaced, or during the nightly “Ultra” broadcasts from SubPac commands.
The difference in the two systems was that the U.S. commands did not specifically designate a sub to be a full time shadower, and the movements of wolf packs were the perview of the officer in tactical command, whereas in the German system, the sub command ashore directed the wolfpacks.
[QUOTE=Little Nemo]
Another factor was determining the long range route of the convoy. If the convoy just headed in a straight line than any submarine or plane could observe their current course and speed and easily predict where they would be several hours in the future. A quick radio call could then summon other submarines to that point to await the convoy. By zig-zagging a convoy could conceal its true course from an observer.
eta: Rereading the OP, I see it already mentioned this.
[/QUOTE]
Whoah, I just thought of zig-zagging in the second harmonic. Crazyness.
[QUOTE=treis]
It’s likely due to the way that they had the subs coordinate. Coordinate for them meant that all the subs responded if one detected the ship. Coordinated to me means having spotter subs and hunter packs working together.
[/QUOTE]
Sorry, I’ve expressed my point poorly. My point is that intuitive logic is unlikely to lead to an answer to your question.
For example: “The target’s turn is likely to bring it into the firing range of another sub”
…How likely is it? What if the target turns more than once? How far does the target have to continue on that course in order to be ambused by a different submarine? How close do the submarines of the wolf pack have to be to gain an advantage over zig zagging cargo vessels?
There are too many variables to simply assert that zig zagging should be avoided because you’ll just run into another submarine.
One of the huge innovations of World War II was the development of Operations Research, the idea that common sense and intuition are insufficient to answer these sorts of questions, and instead we need to use mathematical/statistical models to determine non-intuitive solutions that, on balance (but not in every case,) will lead to success. Wikipedia has an article on it that summarizes some of the importance of operations research. For example, in World War I it was believed that sailing ships in convoys made them more vulnerable to submarine attack because if located, they would all be found rather than just one of them. The experience of World War I proved that convoys worked, but no one knew whether large or small convoys were better. Operations research demonstrated that intuition aside, even a few large convoys were safer than more smaller convoys, which was safer than ships sailing alone.
In the case of zig zagging,
(From the powerpoint presentation available here)
We don’t know the mathematical solution. But that does not mean that we can reject the hypothesis that zig zagging could be useful.
Or, put another way, our brains are so well designed for the task of catching something in motion while moving ourselves that it’s hard to appreciate how difficult the task is with a slide rule and a chart.
[QUOTE=wevets]
Sorry, I’ve expressed my point poorly. My point is that intuitive logic is unlikely to lead to an answer to your question.
For example: “The target’s turn is likely to bring it into the firing range of another sub”
…How likely is it? What if the target turns more than once? How far does the target have to continue on that course in order to be ambused by a different submarine? How close do the submarines of the wolf pack have to be to gain an advantage over zig zagging cargo vessels?
There are too many variables to simply assert that zig zagging should be avoided because you’ll just run into another submarine.
[/quote]
I don’t disagree that zig-zagging is better in an submarine encounter than not. My argument is that the increased chance of having a submarine encounter is worse than the increased chance of surviving a submarine encounter.
[QUOTE=treis]
I don’t disagree that zig-zagging is better in an submarine encounter than not.
[/quote]
That’s the interesting catch - a convoy ship doesn’t know it’s in a submarine encounter or not until it’s too late, so a captain must make the decision before the submarine encounter.
But how do you know that?
According to the quote above, wartime researchers couldn’t collect the data to analyze the problem.
What might be the best substitute is a computer simulation, run many times over, of realistic ship speeds and U-boat wolfpack behavior. I don’t know if that’s been done, and the information linked to by WoodenTaco in post #2 of this thread implies that it hasn’t. The analysis in the powerpoint seems to be as close as it gets.
[QUOTE=Declan]
…Practically speaking , zigzaging may have been useful in the first world war , but by WW2 it was probably a morale effort for the merchant crews to actually do something.
Declan
[/QUOTE]
Wrong. Zigging is useful to the present day (though the engagement ranges have increased by several times from those of WWII).
I’ve been in exercises where we repeatedly “sunk” one vessel, but rarely scored a hit on another due to the latter’s zigging. We’d get a good firing solution, get off an exercise torpedo, only to have the zigging target change course by 60-80 degrees. This then required a huge course change for the torpedo, and often the torps ran out of fuel before reaching the target.
[QUOTE=robby]
Wrong. Zigging is useful to the present day (though the engagement ranges have increased by several times from those of WWII).
I’ve been in exercises where we repeatedly “sunk” one vessel, but rarely scored a hit on another due to the latter’s zigging. We’d get a good firing solution, get off an exercise torpedo, only to have the zigging target change course by 60-80 degrees. This then required a huge course change for the torpedo, and often the torps ran out of fuel before reaching the target.
[/QUOTE]
How much would doing a zig-zag pattern like one in the linked PowerPoint reduce the probability of a torpedo hit?