Am I doing evasion wrong or what's up with this movie clip?

[BanDHMO]

Either my tactics when being waterbombed are wrong or the movie is, but I couldn't help thinking "WTF is he doing?!" when I watched it. See for yourself:

https://www.youtube.com/watch?v=uBTcjLc2FTM&t=15s

Apparently, he's running silent and being pinged, at a depth less than 120m, since later he'll sink to that level as a result of damage.

Here, already, I'd be assuming I'm about to be detected if not already detected, and preparing to go loud and evade. The captain just hangs out with a dramatic face doing nothing useful.

And why is he over 120m, anyway?! Your crush depth is 250m, and the more water you have between you and the hunters, the better.

A couple of seconds later, the hydrophone operator reports depth charges in the water.

Now you're DEFINITELY detected, there's no point in hiding. You need to go full ahead, change depth and possibly turn - ANYTHING to not be in the same spot you were when the charges were dropped. Run, weave, launch bubblemakers, then go slow and silent again, hoping they will lose the exact fix on your position while the explosions blind them.

Instead, the captain stays standing around as he was, useless, delivering some stupid dramatic remark. "The Tommies are crapping at us." His name might as well be Kaleu Obvious.

Predictably, the boat takes damage. Report comes in that she's sinking and at 120m.

OK, that's bad, but you were supposed to be trained for emergencies. Crush depth is around 250m, less so with a damaged hull that your incompetent ass just caused, but still, she should hold while you try other means to get her stabilized. Empty the tanks gradually, go full speed and try to climb up to compensate. Yes, you'll be easy to detect, but at periscope depth you still have a chance with a scattershot salvo because the DDs have to come right on top of you. And if you happen to have a sound-homing torpedo ready, which you should've tried your best to have, then even better.

But no, the captain immediately orders to blow tanks, thus shooting the boat up onto the surface, where she is a sitting duck to be murdered by DD's deck guns from afar.

Seriously, I don't know the plot of the movie, was he trying to surrender the boat to the Allies on purpose?

[El Rushbo]

Well, in early to mid-1942 they had no homing torpedoes, or likely even bubblemakers.

As far as blowing tanks to get to the surface, that's not as dangerous as it sounds given it was night. Radar wasn't as common on escort ships yet, and U-boats were practically invisible on the surface at night. As far as crew incompetence, that isn't too far off the mark either. U-570 was captured due to the crew being panicked after taking damage and surrendered to the British. Further examination showed that the damage was fairly minor and could've been quickly repaired. Had a more experienced crew been aboard, it's likely U-570 would've gotten away. (Instead of later becoming the HMS Graph)

But it wasn't that uncommon for a U-boat to slip away on the surface at night.

As far as just sitting in a slow straight line while the depth charges hit, well that's Hollywood for ya.

[wolf310ii]

Originally posted by BanDHMO:

Either my tactics when being waterbombed are wrong or the movie is, but I couldn't help thinking "WTF is he doing?!" when I watched it.

U-571 is a crap movie.

And why is he over 120m, anyway?! Your crush depth is 250m, and the more water you have between you and the hunters, the better.

Going at the first sight of an destroyer to crush depth is computer game tactic.
U-Boats prefered to stay at 50-150m, the deeper an u-boat goes, the more fatal leaks become. At 100m the boat already can only blow the main ballast tank 3, so the deeper the boat goes the less it can counteract flooding by blowing ballast tanks.

A couple of seconds later, the hydrophone operator reports depth charges in the water.

Now you're DEFINITELY detected,

Depth charges in the water means not the boat is detected.
On the last few hundred meters the destroyer was blind, so the CO, knowing that a u-boat can hear the depth charges being dropped, had to guess what evasive manouver the u-boat will take and still dropping on wrong position.

there's no point in hiding.

If there is more than 1 destroyer, then yes, there is a point in hiding.

OK, that's bad, but you were supposed to be trained for emergencies. Crush depth is around 250m, less so with a damaged hull that your incompetent ass just caused, but still, she should hold while you try other means to get her stabilized. Empty the tanks gradually, go full speed and try to climb up to compensate.

Like i wrote above already, at 250m you dont have the air to gradually compensate for leak, wich are far worse than at 150m.
At 250m even a full emergency blow will raise the boat only slowly and become gradually faster with the expanding air in the ballast tanks, but only if the gain of buoyancy stays bigger than the loss of buoyancy due to flooding.

In the book "Feinfahrten" from Wolfgang Hirschfeld, they escaped an hunter killer group, waiting in an half circle around their position with stopped engines, by slowly surfacing at night and sneaking away on the surface with e-motors.

[BanDHMO]

Originally posted by wolf310ii:

Depth charges in the water means not the boat is detected.
On the last few hundred meters the destroyer was blind, so the CO, knowing that a u-boat can hear the depth charges being dropped, had to guess what evasive manouver the u-boat will take and still dropping on wrong position.

If there is more than 1 destroyer, then yes, there is a point in hiding.

He doesn't have the exact fix on you the moment he's bombing, but he does know where you are if you just heard him pass over you and drop charges. It wasn't just a happy coincidence that he decided do randomly throw depth charges overboard when he was right on your position. He knows, and he's presumably told to his allies he has you. Once he turns, he will see your exact position again, because you won't get far in that time if you are still crawling. You are crawling at maybe 3 knots, he's going at 10 times that speed. So you either run while he can't hear you, or you will be taking another batch of depth charges soon, and then another, and another. With a second DD it's harder, but you still have a window of opportunity to be loud because nobody can hear you while the depth charges are blowing up nearby.

So, the moment depth charges are in the water, you go full loud and MOVE. Yes, the position is revealed to other DDs, but they already know it anyway. And if you don't move, you likely die right then, so any side-effects that aren't immediate death are acceptable. When explosions are about to stop, go back to crawling.

Going at the first sight of an destroyer to crush depth is computer game tactic.
U-Boats prefered to stay at 50-150m, the deeper an u-boat goes, the more fatal leaks become.

Even when they were being hunted? I get that there are plenty of downsides to being deeper, but we're not talking about a recreational trip. You have barrels of explosives thrown at you from above and whether you can dodge them enough determines if you live or die. Obviously, you wouldn't go right to crash depth, but 50m doesn't sound survivable in a fight. You might as well just surface and surrender at that point.

Speaking of sneaking away on the surface after blowing tanks, I don't think I'd count on it as a general tactic. The conditions would have to be just perfect or it's less doable than staying under. There's no blind spot when you are on the surface, no such thing as they passed right over you but didn't notice, the sighting range wouldn't be too bad even at night, and worst of all YOU can't see them much better than they can see you. Maybe if it's a moonless night and/or fog/rain, etc. None of that was the case in the final scene of the clip. The sky is fairly clear with the moon out, only obstructed for a moment by a lone cloud. I'm sure surface escapes happened in reality sometimes, but those stories would be notable exactly because they were rare.

[Wyzard]

what use is toilet paper , i want a full History lessen - NOW

[athenian]

U-571 is not a good U-boat movie. How about that torpedo scene at the end? One in a million chance, but they got it. I wouldn't take it too seriously in terms of U-boat tactics.

[Grumpy Old Dude]

movies...have a script

[wolf310ii]

Originally posted by athenian:

U-571 is not a good U-boat movie. How about that torpedo scene at the end? One in a million chance, but they got it. I wouldn't take it too seriously in terms of U-boat tactics.

That wasnt even the worst of the movie.
The scene with the leak "Captain, i cant reach the valve, my arm is too short" "Close that valve, thats an order" "Oh in that case i can reach it, no problem, i just grow a longer arm"