Das Boot Surfacing Scene

[Bgile]

Well it did work, so ...

Of course, there may well have been subs lost while trying it as well.

[tommy303]

As Bgile says, it did work on some occasions at least; and there may have been others when it didn't but there were no survivors to describe the failure. Edward L Beach has his main character in 'Run Silent, Run Deep' drilling his crew for just that sort of bow on shot and pulling it off successfully, if I recall. As Beach himself was a successful submarine commander in the Pacific War he would have been aware of all the difficulties of such a shot and its slim margins of success. If one is fortunate enough to be in a position to set up the shot, and that would mean not having to make a large turn to bring your bow or stern tubes to bear, then you might be able to pull it off. Whether or not your torpedoes will cooperate is the question. A single torpedo would probably not be enough, and one would probably need to fire at least two and better yet four in a narrow spread. It then becomes a game of chicken for the destroyer commander--does he keep on course and hope that the torpedoes will miss or be ineffective, or does he chicken out and try to turn out of the line of fire. If he turns, the chances of being hit by the spread increases as he probably can't manouver out of the line of fire at such short notice. One hit is enough to put him out of action or send him to the bottom, provided your torpedo's pistol fires properly. I suspect a reliable magnetic pistol might be better than an impact one at such oblique angles; never the less the hydrostatic pressure wave produced by the ship cutting through the water might actually conspire to cause a hit rather than the other way around. The tendency would be for the pressure wave to deflect the torpedo away from the hull, but the guidance system would sense the change and probably over compensate and actually swing the torpedo back towards the target at a less oblique angle for impact at some point near aft of the bow section.

[Bgile]

The hydrostatic pressure change might also set off the torpedo, which would also be bad for the destroyer. Contact exploders were known to go off when entering a ship's wake.

[marcelo_malara]

Which was the accuracy of a torpedo in WWII, degrees or mils, anyone can tell?

[tommy303]

I don't think you can put torpedo accuracy down to mils or even degrees as over distances the torpedo can be affected by wave action and currents causing it to drift from its course in a way not easily predicted from the firing platform.

[tommy303]

The hydrostatic pressure change might also set off the torpedo, which would also be bad for the destroyer. Contact exploders were known to go off when entering a ship's wake.

Very close non-contact explosions can sometimes be more harmful than a contact one.

[marcelo_malara]

You are right Tommy, the gyro cannot detect the drfit.

[marcelo_malara]

What would the effect of a high angle explosion be? The damage pattern of a torpedo explosion is commonly an elongated area left and right of the impact. In this case (suppose a starboard impact) the left "damage area" would be to the sea, the right one right into the ship. Would it be a highly localized but deeper damage?

[tommy303]

a normal explosion in water is pretty much spherical with the force radiating outwards from the point of detonation. In the case of a contact explosion, a good portion of the force is concentrated against the side of the ship and much of the resulting energy is spent destroying the shell plating and structures beyond it, leaving the remaining energy to vent both into the ship through the ruptured plating as well as upwards to the surface. The deeper the contact explosion the better as the water tends to hold it against the ship and more of the explosive force vents into the hull. The effects, on the whole are localized to a degree, as on a large ship the effect might be confined to just one compartment unless the detonation occurred near a transverse bulkhead.

In a close non contact explosion, the detonation of the warhead has time to develop and actually covers a larger area which may affect not just one compartment but perhaps compartments to either side of the one hit. The expanding bubble from the detonation will hit the ship with more of a blunt force, caving in and rupturing plating over a greater area and will frequently cause much more secondary shock damage to equipment throughout the ship. This is one reason why magnetic pistols were desirable if they could be made to work reliably, as they are by nature non-contact and with the force under the hull, will have a greater chance of breaking the back of a ship.

So long as detonation occurs, either contact or non contact, the actual angle of the torpedo strike has little effect as far as I know.

[Bgile]

I think we can safely assume that a torpedo warhead exploding away from a ship would have a circular blast effect similar to a bomb. If it were to explode within a short distance of the destroyer it would likely open up the hull, and a small ship going 20+ knots is likely to suffer very fast progressive flooding under those circumstances.

Edit: Tommy beat me to the punch!

[RF]

The view shown in the periscope would have the destroyer at less than 1000 metres, insufficient time to launch the torpedoes let alone arm them.

How do you know what power he was using?

I don't. I am going on what was actually shown on screen and the commander's reaction to it.