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