Silent Hunter (e)

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SILENT HUNTER

The Wolf's Den
Strategy and Tactics

Theory, Strategy, and Hints will take up the space on this page.
Most of the tips here will have been sent to WolfPack or
discovered through the NewsGroups ( a wealth of information for
tactics). Enjoy...and I hope this improves some scores!

From BdU:To all Boats:Some tried and proven tactics for use
against convoys.

Listen to the pattern of the Asdic as you are being tracked by the
escorts. The Ping is Asdic signals going out and the Pong is the
return from your boat. If the Pong is missing, the escorts do not
yet have your position pinpointed.

Keep the Gyro angle low. The greater the distance to your target,
the greater the angle that the torpedo will have to travel to
intercept.

When the escort makes a run at you, at the moment that the ASDIC
pings stop, make a hard course change to shear off. The change
will put you at right angles to his attack and may get you out
from under the depth charges.

If you are detected, dive under the convoy. All of their noise may
help mask your boat from the ASDIC search. Then cut your engines
to 1/3 until the Pings quiet. Remember that Otto Kretschmer's
favourite tactic was attacking from within the convoy. The escorts
had a very difficult time determining your position and in the
confusion, you may score some very big hits. Surprise is your best
chance and the convoy never expects you to be in the middle of the
columns.

Try attacking from the front of the convoy, where you can lie in
wait. It is tougher doing an end around and you may be detected.
At night, surface attacks are a must and give you the best chance
of working in close to the
convoy...approach slowly!

During day attacks, get in front to intercept then drop to
periscope depth and wait. I rarely am detected when I have been
waiting for some time and come to periscope depth and fire
quickly. Do not give the escorts time to trace the origin of the
attack. If they detect you, go deep and run dead slow. In shallow
water near coasts there may be cold thermal layers that can help
mask your presence.

Thanks to Ken Fishkin and his trigonometry for the following
tables....

They may help with some of the angles!

TABLE 1: DESIRED ANGLE TO TARGET:
Suppose the target is D meters away. You wish to shoot ahead of the
target and be positioned such that when the target is K meters directly ahead
of you it'll be a close, straight-on shot. This requires that when you're
perpendicular to the target, your bearing to it be arccos(WD). Here's
sample values of this, with D going from 1 to 20K, and K at 400 and 500:

D K = 400 K = 500

1000 66.4218 60
2000 78.463 75.5225
3000 82.3377 80.4059
4000 84.2608 82.8192
5000 85.4114 84.2608
6000 86.1774 85.2198
7000 86.7242 85.904
8000 87.134 86.4167
9000 87.4527 86.8153
10000 87.7076 87.134
11000 87.9161 87.3947
12000 88.0898 87.612
13000 88.2368 87.7958
14000 88.3628 87.9533
15000 88.4719 88.0898
16000 88.5675 88.2092
17000 88.6517 88.3146
18000 88.7267 88.4082
19000 88.7937 88.492
20000 88.854 88.5675

If your actual current bearing is LESS than this, then you'll be too far away
If your actual current bearing: is GREATER than this, you'll be too close.

TABLE 2: WHEN TO SHOOT

Suppose that the target is presently D meters away, and you are lined
up perpendicular to it. Suppose that the target is at speed S. If you
fire when the target is directly in front of you, your torpedo will
actually have to veer off at an angle, since the ship is steaming away.
At higher speeds, this can be significant. Instead, you want to fire
before that, when the torpedo should hit if fired directly
straight - lead the target.

Assuming the target is moving right to left,you should fire when the
target is at (theta) degrees, where theta = arctan(S/s), where 's' is
the speed of the torpedo. Setting's' to 30 (the onIy speed I've
seen so far), you get the following table:

TARGET SPEED - FIRE WHEN AT BEARING

2 3.81407
4 7.59464
6 11.3099
8 14.9314
10 18.4349
12 21.8014
14 25.0169
16 28.0725
18 30.9638
20 33.6901
22 36.2538
24 38.6598
26 40.9144
28 43.0251
30 45

You can reach me by e-mail at: jjochen@mnsi.net