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Library: underwater devices / evasion
Books
Author: Lum
Date:Jul 23 1998
This book is about what to do if you are in a submarine and someone fires a
torpedo at you. It is very important to know this, so you had better read it.
0) You want to detect the torpedo as early as possible. Early on, you have
the most options and greatest chance of evasion.
1) If prudent and possible, dive or rise to one TL above or below device.
2) Immediately turn perpendicular to device and make for standard bell (at
minimum). If the device is close, your best chance is to try to cut it off by
heading towards it (about 30 degrees off the perpendicular). Otherwise, head
away.
3) If you know device came from a surface contact, launch a torpedo at the
bearing equal to the device (to put the ship on the defensive).
4) While still on the TL of the device, launch a decoy countermeasure. DO NOT
use a jammer countermeasure (yet). Launching the countermeasure before the
device has started active homing will give you an advantage.
5) If you are confident you will be out of the homing arc of the device when
it activates, close on the hostile surface contact and fire (if prudent). Or,
just get out of the area.
6) If you cannot escape in time, the device will start active homing. If you
do not have an active decoy out, launch one immediately. Turn 45 degrees away
from the perpendicular, heading away from the device.
7) Make for flank speed, possibly change depth or heading.
8) Hopefully, the device will pursue the decoy. When the device reaches a
decoy, it will either explode or start searching. So, always try to put a TL
between you and decoy. Take the SST of the surrounding sea into account. In
most cases, sound travels toward the surface, so you will want to leave a
decoy near the surface and then dive.
9) If the torpedo re-acquires you or ignores multiple decoys, turn directly
away form it and release a jammer. Wait for the torpedo to enter the vicinity
of the jammer and then quickly turn directly perpendicular to it. Fire a
decoy. Reduce speed to standard (or slower).
10) If torpedo is very close, go deep and return to flank speed. Fire
multiple jammers as you descend. Go really deep (as deep as you can, even
past 900 feet if you want) and release a decoy at the maximum depth. Turn
perpendicular to the device's path and fire another decoy. As the torpedo is
really close, perform an emergency blow, this will give you an extra burst of
speed. Make sure you turn away from both of the decoys (they're fired at
roughly right angles). Level out depth at around 250 feet (try to avoid
cavitation) and reduce speed to 1/3rd or less. Don't repressurize the main
blower yet, it's too noisy.
Some other tricks you can try:
Fire a torpedo directly behind you. Once the torpedo is a slight distance
away, get it between the enemy device and your ship and then set it to active
homing (on your sub). Disable it before it gets too close (to detonate) and
go back away from your sub. Repeat. This can seriously confuse the homing
logic of the enemy device, b'cos it detects not only it's own active sonar but
your torpedoes active sonar also. It helps if your torpedo is the same exact
type as the enemy one, though. Don't do this for very long, quickly launch a
decoy and make your torpedo home in on that (and detonate). The noise
pollution following the explosion will give you another chance to escape, it's
even better than a jammer.
As a last resort, you can try to use the ocean floor or such (head toward the
ocean floor, almost touch it, close the range and then emergency surface) but
most of these things are desperation moves.
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