prob sub
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.::..
SIERR SSN
A GAME OF
NUCLEAR
SUBMARINE COMBAT
STURG ON
SSN
By
R
PRESCOTI and
A
AMOS
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0.0
0.0.1
0.0.2
0.0.3
PROBSUB
is a
set of
rules which
simulates
modern combat between
nuclear
submarines, and also includes anti-submarine
aircraf t
and helicopters.
All aspects of anti-submarine
warfare
are covered, except
the
use of
surface
vessels. However,
it
i s hoped that there will be an update
to
PROBSUB in
the
near future which will cover the use of surface vessels in the anti-submarine
role
as well as
targets.
I t
i s possible
to
play PROSUB without any models at a l l by plotting al l
the
action on a chart see map , but this does lose some visual apeal.
The use
of an
umpire
does
make
the
game more
real i s t ic
but i t is quite
possible
to
play the
game
without one.
April
1990
R Pescott and A Amos
2
Glenfield
Road,
Dover
Kent
CT16
2AL
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VICTOR 1/11
SSN
Copyright
R.Pescott,
A Amos
arid
Tabletop
Games
April
1990.
I l lus trat ions
by
Sarah
Amos
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CONTENTS
REF
SECTION
0.0 Introduction
0.1
Background Notes
0.2
ACI IVE SON R
0.3
PASSIVE SON R
0.4 Towed
Arrays
0.5
Thermal Layers
0.6
Noise
0.7
EXPLANATION OF TERMS
1.1
SCALES
1.2
EQUIPMENT REQUIRED
1.3
UMPIRES
2.0
SEQUENCE OF PL Y
3.0
COMM ND
PHASE
4.0
MOVEMENT
PHASE
4.1
Lateral
Movement
4.2 Speed Changes
4.3 Turning
4.4
Williamson Turn
4.5
Depth Changes
Hydroplanes
Ballast
4.6
Maximum
Safe
Depth
4.7
Mine Activation
Subphase
4.8
AERIAL OPERATIONS
4.9
Collision
=
4.10
M.H.D.
PROPULSION
5.0
COMMUNICATIONS
PHASE
5.1
E.S.M. Subphase
5.2 Radar Subphase
5.3
Visual Subphase
S.4
E.L.F.
Subphase
5.S
V.L.F. Subphase
5.6
LF/HF/VHF/UHF
Subphase
S.7
U.T Subphase
6.0 SON R
PHASE
6.1
Passive Sonar Efficiency
6.2
Sonar
Detection
6.3
Acoustic Masking
6.4
Notes on
Towed
Arrays
6.5
Towed
Array Sub phase
6.6
In Hull Passive
Sub
phase
6.7
Active Sonar Subphase
6.8
Passive
Dunking Subphase
6.9
Active
Dunking Subphase
6.10
Passive Sonobouy Sub phase
6.11 . Active Sonobouy Subphase
6.12
Surveillance Subphase
6.13 M.A.D.
Subphase
6.14
Sonar Detection Example
PAGE
No REF
SECTION
PAGE No
1
7.0
T.M.A. PHASE
30
3
3 8.0 WE PONS PHASE
32
4 8.1
Wire Guidance
32
4 8.2
Torpedo Sonar
32
5
8.3
Torpedo Loading
33
5
8.4
Pre-Launch Program
33
6 Subphase
8.5
Tube
Cap
Subphase
33
7
8.6
Standoff Weapons
Subphase
34
7
8.7
Torpedo Launch Subphase
34
7
Counter Fire Torpedoes
35
8.8
Sensor Deployment Subphase
35
8
8.9
Post-Launch Program Subphase
35
8.10
Decoy
Program Subphase
35
9
9.0
TT CK RESOLUTION
PHASE
36
9 9.1
Hit Probability
36
9
9.2 Aquisition
Percentage
36
9
9.3 Decoy
Launch Subphase
37
10
9.4
Decoy Resolution Subphase
37
12 9.5
Noisemaker Subphase
38
12 9.6
Impact
Resolution
Subphase
38
12
9.7
Damage
Resolution Subphase
38
14 9.8
Nuclear
Weapons
40
15
15
10.0
RECORD
PHASE
42
16 10.1
SUBMARINE STATUS SHEET
43
17
17
11.0
OPERATIONAL
FORM T
44
11.1
Movement
on
Charts
44
18
11.2
Movement
on
Table
44
18
11.3
Starting the Game
on
Table
44
19
19
12.0
ARCTIC OPERATIONS
45
20 12.1
Ice 45
20
12.2 Sonar
in
the Arctic
45
20 12.3 Ice
Extent
Chart 46
20
13.0
AIRCRAFT
D T
SECTION
47
21
22
14.0
TORPEDO D T SECTION
49
23
14.2 Standoff Weapons 49
25
14.3
Anti Ship
Missiles
SO
26
14.4 Cruise
Missiles
SO
26
27
lS.0 SUBMARINE D T
SECTION
51
27
27
16.0
CHARTS
54
28
16.1
Turning
Scale
54
28 16.2 Depth Change Charts
55
28 16.3
Submarine Speed/Noise Chart
56
28
16.4 Torpedo Speed/Noise Chart
57
28
29 17.0
ABBREVIATIONS, PHRASES
58
TERMS
18.0
BIBLIOGRAPHY
S9
19.0
DEPLOYMENT
EXAMPLES
60
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0.1 BACKGROUND
NOT S
In
the following
notes,
the
term vessel , means any submarine
or
surface
ship.
0.1.1 A submarines greatest
asset is
stealth,
in
i t s
basic meaning. A submarine
i s
capable of destroying just
about
any
adversary, with
the large c h o ~ c e of very
high-tech weapons available to i t ; but this task is much easier i f the
attacker
can remain undetected.
Therefore,
submarine combat
i s
a complex game
of hide-and-seek;
with
each
submarine
trying
to
detect his opponent,
whilst
a t
the same time attempting to remain undetected himself.
0.1.2
Thus a submarine
will
do
everything
i t
can
to
remain
undetected,
and
conversely, will do
nothing which will
give away i t s own position, except
1n
dire emergency.
0.1.3
Although
nuclear
submarines have virtually no need to surface while operating,
they do
have
to
raise a
periscope or antenna
in order to detect aircraft and
helicopters; or to monitor radio and radar transmissions. These periscopes and
antennas must
protrude
above the surface, and
so
are detectable
by surface
and
airborne
units:-
a)
I f
the submarine i s moving at more than 5 knots, then a wake will be
formed by the periscope
or
antenna. This
i s
often more
easily seen than
the .actual periscope or antenna i t se l f In any case,
at
speeds over 16
knots,
the periscope or
antenna
will suffer damage.
b Modern surface search radars are now
so
sensitive, that even the t ip of a
periscope
or
antenna
will
probably
be
detected,
i f
someone
is
looking,
and
they
are
closa enough.
c) I f the submarine transmits, with
either
radio or radar, then there
is
a
chance
that
these emissions will be detected by listening enemies, and this
can
give
away
a
submarines pOSition.
0.1.4
As
can
be
seen, radar
i s only capable of
detecting
surface or airborne
, targets, and is a ~ m o s t certain to give
away
the
submarines
position.
As
such,
i t i s
very
rarely used.
0.1.5 The
Ocean is a dark place.
Light,
the basis of vision, does
not
penetrate
more
than about 3 m below
the surface,
a t
best,
so any
visual
means of
detecting
another, submerged submarine is out of the question. A
raised
periscope may
allow
the
detection
of surface or airborne
units, but
risks the submarines
detection.
0.1.6
The
best
medium
a
vessel
can use
to detect
submerged
targets
and
threats,
is
0.1.
7
0.2
sound, and the apparatus which uses sound
for
detection
purposes, is
called
SONAR
Sound
travels through water better than i t
does
through air,
and
in the right
conditions i t i s possible to
detect
sounds coming from hundreds of kilometers
away.
There are two types of sonar, and they use
the
sound waves in different ways:-
0.2.1 a) ACtIVE
SONAR
An active sonar
set produces
high frequency sound waves, and actually
transmits them out into the water, in a more or less directionall beam.
0.2.2
The
sound waves bounce back from an
object,
and
these
returning
waves
are
received by the sonar apparatus. Computer analysis of this return echo can
give the range, bearing,
speed and depth of
the object,
according to the
strength of the return
Signal.
0.2.3
The problem
with active sonar
is
that
the
radiating
soundwaves can be detected
by anyone listening, and a t a range greater
than
their own
detection
range.
Thus, use of active sonar is rather like shouting out your position, while
anyone listening
will
only reply in a
whisper.
0.2.4
Only search for your opponent with
active
sonar i f he already has your
pOSition, and you are desperate.
0 2 ~
Active sonar
may
be used for mapping the terrain of the sea bed, or of
overhead
ice,
or for detecting mines.
In these
cases, i t s maximum effective
range
i s
2 kilometers.
0.2.6
Active
sonar
in
i t s
search
mode
has
a
maximum
range
of
60
kilometers.
I t
may
not be used at
speeds
of over 25
knots.
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0.2.7
0.2.8
0.3
0.3.1
0.3.2
0.3.3
0.3.4
0.4
0.4.1
0.4.2
0.4.3
Active
sonar in
vessels cannot
detect torpedoes.
However, torpedoes which have
approached a target uSing
passive sonar,
will normally go act ive , or switch
to
active
sonar in
order to aquire
the
target.
Active sonar is .aunted
in the
bow of a ne, and so can only cover an
arc
of 30
degrees
either side of the ships
head.
This
does
not apply
to
sonobouys
or
to dunking
sonars
from helicopters.
b)
PASSIVBSONAR
A
passive
sonar
set
does not
radiate
sound waves
in
the
way
that active
sonar
does. I t is
purely a listening
device. As
a
vessel
moves, i t will
generate
noise; from
i t s
engines, from
i t s propellers,
and from the turbulence
in
the
vater that i t s passage ukes.
An in-hull passiye sonar (ie. one .cunted
inside
the
vessel),
may be
able
to
detect
these noises
at a range
of
up
to
120
kilometers.
The
noises
a vessel
generates
are
often unique to that vessel, and so by
consulting
an on-board
l ibrary,
the detecting vessel
may be
able to
positively identify i t s
target.
As passive
sonar
does not radiate any energy, there is
no
way that a target
will know that he
has
been detected; and there is no chance that
the
detecting
vessel will give away i t s position.
Passive sonar is
greatly
affected by the detecting vessels speed. Sonar
efficiency begins to fa l lo f f above 12 knots, and is useless above 22 knots.
Noise from
the detecting
vessels
engines
snd
propellers
will
produce a
blind
zone directly aft
of the
vessel, eyen i f
the
engines are stopped. This means
that
sonar is completely inneffective
in
a 60
degree
are, centred directly
astern. I t
also
means that any torpedo
approaching
from within this arc will
be undetectable to in-hull
sonar.
a spec
kind of passive sonar
set , called a TOWED ARRAY
This
is a
string
of
passive sonar detectors, which is streamed along behind the vessel,
and may be
in
the order
of
560m
long
By
virtue
of
the fact that the towed
array
. is distanced from
the
towing
vessel, i t is unaffected by any noise that vessel is making.
I t
is therefore
much more sensitive than an in-hull passive sonar, and lilly detect targets up
to
280
kilometers
away.
HaYing a towed
array s t
will
impose
restr ict ions on
the vessels
l i ty
0 5 mERHAI.
LAYERS
As will be seen from the previous
section, noise
sound waves) is
both
a
friend
and a enemy. These waves
of
sound can be affected by
the
varying
conditions of the
water through which
i t
passes. The
waters of the
Ocean are
far
from unifora and are not stat ic Currents produce bands of water which
have different
density,
temperature and
salinity
and these differences
co.bine
to produce a IlIERMAL LAYER.
0 5 1 A body
of
water at depths between either
the
surface and a thermal layer,
between two
thermal
layers or between a
thermal
layer and the
sea
bed is known
as
a
DUCT
0.5.2 A thermal layer
is able
to
reflect
sound waves which come
down
to
i t
at an
angle, so sending them back up. Similarly, sound wayes coa1ng up to a
theraal
layer will be
reflected
back down. Thus a Bub-arine in one duct,
may reasin
undetected,
even though
without the layer, i t
would be easily
detected.
0.5.3 Exaaple
of
thermal
layer
and i t s
effect.
...
..
.
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SURFACE
Searching
Submarine
\
\
searching submarine
{
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HERMAL
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0.5.4
0.5.5
0.5.6
0.5.7
To make
matters
more
complex, sound
waves approaching the thermal layer
at
certain
angles,
will be allowed
to
pass through the
thermal layer unaffected.
This tends
to
be
very
unpredictable.
ONVERGEN E ZONES
Another curious effect the water
can produce, i s
the
formation
of Convergence
Zones.
When sound waves radiate downwards into very
deep
water, over 2000m),
a
combination
of the
water
pressure and the
thermal layers
bend the beam more
and more, unt i l i t
i s
directed up towards the surface again.
This
beam manages
to
pass through
a l l thermal
layers.
When the now bent beam reaches the surface,
i t
is reflected back down
again,
to repeat the effect , though
now
with reduced power. The
following
diagram
shows this effect .
normal
detection limit
I
I
I
I
I
I
SURFACE
THERMAL
-
AYER
areas where detection
is possible
0.5.8 The result of this phenomenon i s
to produce
ring shaped areas around the
vessel, between which sonar detection
i s
not possible.
0.5.9
To combine a l l
these effects
into a
usable format,
thermal layers are
, represented
as
broken l ines on the Sonar Detection Chart see 6.2.3).
0.5.10
I t
will
be
obvious
therefore
that
vessels
will
have to
constantly update
thei r
knowledge of the thermal layers and ducts around them.
0.6
0.6.1
0.6.2
As noise i s a fundemental component of submarine
combat,
i t i s important to
understand how
the game represents i t
For game purposes,
the
magnitude of any
noise
i s
represented as
a percentage.
0 thus
represents
total silence.
100 thus
represents .a maximum
loudness.
All noise percentages are cumulative.
Thus a submarine doing a
speed
which
produces 30
noise, with one tube cap
open (5 ),
and
retrieving a towed array
at
high
speed
(20 ), will be actually
radiating
55 noise.
_ _ ~ ~ c . . . . . ...
CQ
LF
SSN
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0.7
0.7.1
0.7.2
0.7.3
0.7.4
0.7.5
0.7.6
0.7.7
0.7.8
0.7.9
0.7.10
0.7.11
0.7.12
0.7.13
0.7.14
EXPLANATION
OF
TERMS
SSN
- Sub
Surface
vessel,
Nuclear
This
refers to a nuclear powered attack submarine, whose
primary
task is
to
hunt,
and ki l l other submarines.
In
Russia, i t i s ~ o w n
as
a
PLA
- Podvodnaya Lodka Atomnaya.
SSBN - Sub Surface vessel,
Ballistic,
Nuclear.
This refers to a nuclear powered Ballis t ic Missile
submarine;
one designed to
launch
ball ist ic
missiles;
ie. strategic weapons.
The task of these submarines
i s
to
remain
hidden
until
needed.
In
Russia,
i t is known as a PLARB - Podvodnaya Lodka Atomnaya Raketnaya
Ballisticheskaya.
SSGN - Sub
Surface
vessel, Guided, Nuclear.
This. refers to a nuclear powered
guided missile submarine.
These
are
only
operated by the Soviet Navy, and they seem to be angled
against
US aircraft
carrier battle groups. They can
launch
salvoes of
nuclear
or
conventionally
armed cruise
missiles
from a submerged
position.
In Russian i t
is
known as a
PLARK
- Podvodnaya Lodka Atomnaya Krylataya.
SCR M - This is the term given
to
the process where a nuclear reactor begins
to
overheat, and shuts
i t se l f
down,
in order
to prevent a
catastrophic
melt
down.
BATTLE-SHORT
- This is the emergency over-ride a
submarine
. commander has, in
order
to
stop
the
reactor
scramming.
I t is
a
dangerous
step to
take,
as
the
reactor is
moving to a cr i t ical state . As such, i t would only be used i f the
tactical situation meant
that
i t would be even more dangerous
to
suffer a loss
of power at
that
moment.
PROBSUB - Sonar contact is probably a submarine.
CERTSUB -
Sonar
contact
i s
certainly a submarine.
MISSION
IILL
-
Severe
damage, resulting
in the submarine being
unable
to
continue i t s patrol.
TRANSIENT - A
man made
noise. -
TRANSITTER - A
submarine
passing
through another submarines patrol area.
MUTU L INTERFERENCE
- Your
last
target was a friendly.
SOSUS - Sonar
surveillance system
(laid on the sea bed).
GIUI -
Greenland-Iceland-United
Kingdom Gap.
n
area
of
sea
which
acts as
a
bottle-neck for Soviet submarines entering the Atlantic from northern ports
l ike Murmansk.
TARGET
RICH
ENVIRONMENT - Overwhelming enemy
forces.
LYNX HAS.
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1.1
1.1.1
1.1.2
1.1.3
rules
operate
using
the following
game
scales
and
assumptions:-
1
Nautical Mile =
2000
yards
=
2
Kilometers
1
Nautical Mile =
3
inches:
1
Kilometer = 1.5 inches.
1
Nautical Mile per
Hour = 1 Knot
1
inch of la teral
movement - 10
knots
1
Game Turn =
2
minutes of real time
1 Model
or
counter
=
1
submarine, a i rc ra f t
helicopter
or
1
sonar
contact.
All
ranges
on .
the table are measured
from
the centre of the counter or the
model
submarines' fin.
1
Nautical Mile actually equals
6076ft 2025.
3yds L8525Km.
1 . 2 EQUIPMENT REQUIRED
1.3
1. 3.1
1. 3.2
1.
3.3
1.3.4
n
Imperial tape measure (inches).
A number
of
counters
(differing
colours)
for sonar
contacts and
torpedoes.
A
number
of submarine models, preferably in 3000th scale or
similar.
A number
of 3000th a i rc ra f t
and
helicopter models.
1
Protractor
2 10
sided dice.
Sometimes these
are used individually; but where
a
percentage
dice
is called for ( to generate
numbers between 1 and
100), rol l the
two
together. For this case, i t is preferable that the dice
are
of
different
colours,
so that one may represent
tens arid the other the units.
1 20
sided die
1 6
sided
die
Photocopies of the Sonar Detection Chart,
and
the
Submarine Status
Sheet.
Permission
is given
to copy these charts
for personal use only.
UMPIRES
I f
an umpire
i s available,
then the game can be made more
real i s t ic
as
contacts will
only
be announced by the umpire as
they occur.
With
an umpire,
each
player
will
not
move a
submarine
model,
but
will
simply
write his
movement
orders, calculate the noise
levels
generated and
note
the
submarines' new
position on his and the
umpires'
chart . .
During this
phase,
each player must
supply the
umpire
with
the
following
information:-
a) Submarines' position.
b) Submarines' depth.
c) Overall noise percentage, as well as
a breakdown
of the
components of that overall level .
d)
Submarines' speed.
e) Submarines' type.
f )
Torpedoes
position,
depth
and
speed.
g)
Whether
torpedoes are wire guided; runn1ng
what
type of pattern;
or
are
counter
f ire .
h)
Whether
torpedoes are using active or
passive sonar.
The umpire
will then consult
the Sonar
Detection Chart for each possible
contact .
When contact
occurs, he
will notify
the respective player(s) ,
the information
in 7.1.1 or 7.2.1.
However
the
noise
information can
be
presented in one of
two
ways:-
a)
The contacts
total
noise
level can
be
given
to the detect ing player.
b)
The
percentages of a l l the
component
t ransients
(noise
level modifiers),
which make up
the total
noise
can
be
given.
In th is
case,
the detecting player
can
build up a
picture of
what
the
target i s doing, in
order
to
t ry
to predict his actions. I t i s also
possible
for the target play
.
er to produce
a
noise level which i s the
same
magnitude
as
one
of the
noise
level
modifiers;
ie .
a certain
turn
may
sound
l ike a
torpedo launch, etc. in
order to
fool
his
opponent.
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2.0
yers must pe
rm
l l
game
functions according to
the
Sequence
of
Play.
This
regulates the
order of
all
actions into
several phases. Thus players
carry
out these actions
in
turn,
as
phases come
up.
Any actions not carried
out
in
the previous phase must wait unti l the next
game
turn.
2. 1 aJ1I1AND PHASE SEE 3.0)
2.2
2.2.1
2.2.2
2.2.3
2.3
2.3.1
2.3.2
2.3.3
2.3.4
2.3.5
2.3.6
2.3.7
2.4
2.4.1
2.4.2
2.4.3
2.4.4
2.4.5
2.4.6
2.4.7
2.4.8
2.4.9
2.5
2.6
2.6.1
2.6.2
2.6.3
2.6.4
2.6.5
2.6.6
2.6.7
2.7
2.7.1
2.7.2
2.7.3
2.7.4
2.7.5
MOVEMENT PHASE SEE 4.0)
Mine
Activation
Subphase
see
4.7)
Aircraft
and Helicopter Sonobouy Deployment Subphase see
4.8.9)
Collision Subphase see 4.9)
COfoI1UNICATION PHASE
SEE
5.0)
E.S.M. Subphase see
5.1)
Radar Subphase see
5.2)
Visual Subphase
see 5.3)
E.L.F. Subphase see 5.4)
V.L.F. Subphase see 5.5)
L.F/H.F/V.H.F/U.H.F. Subphase see 5.6)
Underwater Telephone Subphase see 5.7)
SON R
PHASE
SEE
6.0)
Towed Array
Passive
Sonar Subphase see 6.5)
In-Hull,
Passive
Sonar Subphase see 6.6)
Active
Sonar Subphase see 6.7)
Passive Dunking Sonar Subphase see 6.8)
Active
Dunking Sonar Subphase see
6.9)
Passive Sonobouy Subphase see
6.10)
Active Sonobouy Subphase see 6.11)
Fixed
Surveillance
System Subphase see 6.12)
Magnetic
Anomaly
Detector
Sub
phase see
6.13)
TARGET MOTION
ANALYSIS
PHASE SEE 7 .0)
WE PONS
PHASE
SEE
8.0)
-
Pre-Launch Weapons Program Subphase
see
8.4)
Tube
Cap
Subphase
see 8.5)
Standoff
Weapons Launch Subphase
see 8.6)
Torpedo Launch Subphase see 8.7)
Sensor Deployment Subphase see
8.8)
Post-Launch Weapons Program
Sub
phase see 8.9)
Mobile
Decoy
Program Subphase see
8.10)
TT CK
RESOLUTION
PHASE SEE 9.0)
Mobile Decoy Launch Subphase see 9.3)
Mobile
Decoy Resolution
Subphase
see
9.4)
Noisemaker Subphase see 9.5)
Impact
Resolution
Subphase
see
9.6)
Damage Resolution Subphase see 9.7)
2.8 RECORD PHASE
SEE
10.0)
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3.0 COMM ND
PHASE
In
th i s
phase,
each
player must determine
exactly
what maneouvres he requlres
his unit(s) to perform in the NEXT
Movement Phase.
This system allows
players
to
move
simultaneously, and
means
that
a players
actions
are based solely On information received
las t turn.
3.1
Such
orders
will
inlcude:-
a) Acceleration
b) Deceleration
c)
Turning
d)
Depth
changes,
due
to
ballast
e) Depth
changes,
due to hydroplanes
f)
Whether .to
switch
on
sensors, such
as M.A.D.
or
radar
g)
Surfacing
h)
Diving
i ) Preparing to
launch
bal l is t ic
missiles
3.2 These orders
should
be
comprhensive
and
specific
.
4.0
4.1
4.4.1
4.1.
2
4.2
4.2.1
4.2.2
4.2.3
MOVEMENT PHASE
In th i s phase, units
are
moved
in accordance
with
the
Movement
Orders
issued
in
the
Command
Phase (3.0);
up
to the physical
l imits
of those orders as
shown.
Units
include
submarines,
aircraf t ,
helicopters,
torpedoes,
standoff
weapons and
mobile decoys.
LATERAL
MOVEMENT
A
uni t s current speed s said to
be
that a t which i t
was
t ravel l ing
a t
at the
end
of
the previous
Movement Phase. .
Lateral
movement
i s determined by
dividing
the current speed by 10.
The
resul t
is the
number
of inches the unit may
be moved this
turn. All l a tera l
movement
of vessels
will create
noise,
the
level of which will rise as the
current
speed r ises . A
slow vessel is
normally a quiet one. See Sonar Phase 6.0.
SPEED
CH NGES
Aircraft
and
helicopters
are c
onsidered
to be able to change speed at
will ,
and
without
penalty.
However,
aircraf t must t ravel above
a minimum
speed to
stay
airborne,
and
this
can
be
taken
as
half
of
the Patrol
Speed,
though they
may make 1 inch
diameter circles.
Due to
range restr ict ions,
assume that
aircraf t and
helicopters may not
exceed thei r Patrol Speed.
For submarines, the maximum
change in
speed possible
(accelerat ion and
decceleration),
will
depend
on
i t s type, and i t s top speed.
The
following
table gives the
maximum acceleration
and decceleration as a
percentage of the submarines top speed,
or
current speed.
ACCEJ.ERATION
or
top
current
4.2.4
The
top
speed
of
each
class
of
submarine is
glven
ln
the
Submarine
Specificat ion
Charts
(see 15.0).
4.2.5 Note
that
the
new speed is attained
a t
the end of the
current Movement Phase.
All actions
up
to the end
of
th i s
Movement Phase
are considered to
have
.
occured
a t
the
speed
attained
by
the
end of
the LAST MOVEMENT PHASE.
4.2.6
A
submarine may continue to accelerate as
per
4.2.3,
unt i l
i t reaches i t s top
speed.
I t may deccelerate as
per
4.2.3, unti l i t s
present
speed
i s
below 5
knots,
when i t
may
stop a t any
time.
4.2.7
Crash
Stop
This
will
reduce the present speed
by up
to 30knots, but will produce 90
noise level
in doing
-
so.
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4.3
TURNIN
Turning
a vessel ,
will
reduce
the
amount of la teral movement i t can
t ravel ;
i t
will
also
generate a certain amount
of
noise.
4.3.1 The maximum amount of turn that a submarine can make will depend on i t s
current
speed. This i s
because the
rudders need a
flow of water
over them, in
order
to produce a turning effect .
4.3.2 A turn will result in: a) A reduction in la te ra l movement.
b)
An increase in radiated
noise.
4.3.3
The
table
following
shows:-
a)
The minimum required speed for any angle of turn.
b) The loss
of la te ra l
movement
caused by
any angle of
turn.
c) The amount of noise
generated
by any angle of turn.
4.3.4
~ o ~ m u m
rent
SPE
duc t ion of La ra.l
fib,
lltage Noise
Turn
Required in
Knots
Movement
in
T
.
-
1
2
0.2
20
2
0.2
6
30
2 0.2 8
40
0,
50
o.
,
60 2
0.2
17
3
0.2
20
3
0.2
22
90
3
0.3 25
100
3 0.3 28
llO
3
0.3
31
120
3
0.3
34
130
< o.
Q
0
0
,
-
2
1-40
1 - , 0
I -
1-80
00
120
l
14 0
I /1.O
1 /80
1 1.00
r-
l
, - 2 ,
o
3
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6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
6.3.7
6.3.8
6.3.9
6.3.10
ACOUSITIC MASKING
I t
is
possible
for
a submarine to hide from
passive
sonar detect ion
in
an
area of high ambient noise;
so
long as any noise
i t
produces is less
than
the
surrounding ambient noise level.
I f a submarine i s stationary in an area of high ambient noise,
such as
under
the Marginal
Ice
Zone with lowered towed
array
so that
i t
gets best detect ion
range, i t will be able to detect and at tack any target
t ransi t t ing
i t s patrol
area, without
any fear of being detected
i t se l f
(unless the
target uses active
sonar) .
If
a
submarine
t r ies
to
hide
up
against
the
ice in
this
way
there
i s
a
chance
of
coll-ision
with the
ice,
the procedure for which is as for case
i below.
The r isk of coll ision may be
negated
by
the use of active sonar
mapping, but
then there is the r isk of detection.
Another way to hide acoustically i s to hold a posit ion
so
close to another
vessel
that their combined sound signature appears as one to another, tracking
vessel , ( ie . one
not in close
proximity).
This third vessel will hear
the
SUM
TOTAL
of the noise coming from both the other two
vessels.
The problem with
th i s
method
is that
the two vessels must come within
half
a
kilometer and 4 m of depth of each other;
this
i s a potential col l is ion
distance. They must also be in the same
duct.
Because the
approach of
the
two
vessels
is deliberate,
the
r isk of coll ision
will be
lower
than normal.
There are two
circumstances
where vessels will merge
thei r
sound
emmissions:-
i A submarine trying to merge with a vessel ,
without that
vessels
knowledge.
i i Two
submarines determined
to merge.
In case
i
above,
the
procedure for the maneouvre is as follows:-
a)
Only the
submarine
making the approach will accept
the
r isk of damage
i f
i t goes wrong.
b)
c)
d
e)
Allow the
submarine
to make the approach; assuming i t i s not detected.
The approaching player rolls a
D20
On a result of 4 or less , a col l is ion
has occured.
Treat
th i s
as
for
normal col l is ion rules
(4.9), except
that the damage
only applies to the approaching submarine, and not the other
vessel .
f)
The
other
vessel
will know
that
a
coll ision
has taken
place.
In case i i above, the procedure i s as follows:-
a)
Allow the submarines
to
approach,
b) Both submarines operators throw a D20.
c) A
resul t of or
2 on either side
resul ts
a coll ision .
1n
d) Both submarines
will suffer
damage as
per
coll ision rules
(4.9).
Once a submarine is acoustically
hidden,
i t
may
e fai r ly easy for a searching
passive
sonar
to
detect the combined
sound
signature, but
very diff icul t to
seperate the two, or even t e l l
that
there
are in
fact, two targets.
In
order for a passive
sonar
to be able to seperate the sound signatures i t
must be able to
detect
a noise
level equal
to the DIFFERENCE
in
noise levels
generated by the two vessels.
The procedure for
passive
sonar
attempting to seperate
two merged vessels is
as fol lows:-
a)
Subtract the noise
level
-generated by one of the vessels from
that
generated by the other.
b) Assuming that
the
combined signature i s within range, then the difference
in noise levels, or less, must be
rolled
on percentage dice, in order for
the searching passive sonar to t e l l that there are, in
fact
two vessels.
c)
I f
the rol l is
unsuccessful,
then only an overall
noise
level will be
detected, and no identification
of
submarine
type will
be possible.
Active
sonar
will
always
be
able
to distinguish
the
two
vessels.
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NOTES ON
TOWED
ARRAYS
A towed array passive
sonar i s streamed astern
on a cable which
i s in
the
order of s60m
long
.
. 1 A streamed towed array puts rest r ict ions on
the
submarines maneouvrability,
and a minimum
current
speed of 4 knots i s required to keep i t
streamed at
the
same depth
as the
submarine .
. 2 At a current speed
of
22
knots
or
more,
the
streamed towed array will produce
20 noise .
. 3 During a Movement Phase involving a turn of more
than
10 degrees, or a change
in
depth
of
more
than
sOm;
AND
for the
2
minutes
1
turn),
af ter
the
maneouvre;
the
Towed
Array will be inoperable, as i t
will
need to se t t le down.
I f the submarine performs a minimum
turning circle
then
the
towed array i s
lost
.
. 4
I t
takes 14
minutes
to deploy or re tr ieve a towed array
a t
slow winch speed,
this only adds 1 noise. I f i t i s retrieved
at
a high winch speed then th is
only
takes
2 minutes but produces a
20
noise level .
. 5 A submarine may jet t ison a towed array
at
any time .
. 6
Some
submarines
only
have a
clip-on
towed array. This must be attached
externally,
with outside
assistance,
(from the dockyard). I t cannot be
retreived
once
deployed but
may be
jettisoned
. 7 A stationary submarine
may lower i t s
towed
array
down, to l i s ten
in
ducts
below
i t s
present
depth.,
or below
i t s
maximum
safe diving depth.
In th is way a submarine will have
the benefit of
maximum
range
on i t s in-hull
passive sonar in i t s
own
duct, as well as
maximum
range
on
i t s
towed
array
in
a lower duct.
.8
Assume
that
a l l towed
arrays
are s60m
long.
At a deployment
ra te of
40m/min,
the time taken
to
reach
a
depth
below the submarine
can
be
calculated.
. 1
The sensing element of the tow i s 60m
long.
After
lowering,
the
now vert ica l
towed
array
will s t i l l require 2 minutes to se t t le down.
TOWED ARRAY P SSIVE SONAR SUBPHASE
Vessels with an operable, deployed
towed array,
passive sonar will attempt
to
detect
targets
as fol10ws:-
a) Check the present
depth
of the searching sonar.
b)
Find the
sonar s
efficiency at the
current speed
(see
6.1).
c)
Plot
the searching sonars depth
on
the
le f t
hand
edge
of the
Sonar
Detection
Chart
(6.2.11).
d) Check the range and depth of the potential ta rget .
e) Plot the potential target, using
the range
and depth scales.
f)
Check to see
i f
the
potential target
is within the detection range of the
sonar
in
use, at i t s present efficiency.
g) I f the potential target is
in
the same duct as the searching sonar; or i f
there are no thermal layers; and i f the potential target is
in
range; then
there i s a
possibility
of detect ion.
h)
I f the potential target i s in a different duct, then there i s only a
possibility
of detection
i f
a st raight l ine can be traced, on the Sonar
Detection Chart
(6.2.6),
from
the searching
sonar to
the
potential target,
without touching one of the solid l ines
representing
the thermal layer.
i
In
other words,
the l ine from the searching sonar to the potential ta rget
must go
through
one
of the
gaps
in
the
thermal
layer,
in order for
there to
be a possibility of detect ion.
j I f such a l ine can be traced, sum up
al l
the noise
percentage
factors that
the
potential target has
produced since the Sonar Phase of the las t game
turn.
k) These factors will include:-
Noise
produced by any weapon
launches last
game turn.
Noise produced by the targets current speed.
Noise produced by
any
maneouvring or
ballasting
by the
ta rget .
Noise produced by any
other
noise factors.
1) The searching player now
rolls
the
percentage
dice. A rol l equal to
the sum
of these
factors,
or
less, means the searching
sonar
has detected, and i s
tracking the
target.
The f i r s t piece of the T.M.A.
i s
obtained, and there
will now
be
an
Effective
Noise
Modifier
for
subsequent
acquisit ion
attempts
(see
7.0).
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6.6 IN-HULL PASSIVE SON R SUBPHASE
6.6.1
6.7
6.7.1
67.2
6.7.3
6.7.4
6.7.5
6.7.6
6.7.7
6.7.8
6.7.9
6.7.10
6.7.11
6.8
6.8.1
6.8.2
Vessels
and
torpedoes with
operable in-hul l , passive
sonar will attempt
to
detect
vessels.
This subphase
is carried out
in
the same manner as the Towed Array, Passiv e
Sonar Subphase previous. The only difference i s that the detect ion ranges will
be
reduced. Remember that
sonars
do not
operate
behind
the
searching vessel
(see
0.3.5) .
oes
with
an
operable
active
sonar
may
i f
ordered, attempt
to
targets .
Active
sonar is capable of
penetrating
thernial layers
to
s
ome
extent. Th e beam
loses one
third
of
i t s
power ie . range), each time i t passes through a
lay
e r .
That
is ,
af ter passing through a
layer, one
third of the
REMAINING range
i s
lost .
I f
there is sufficient range to carry
i t
to another
layer,
then af ter
passing through th i s one,
one
third of the then remaining range will be
lost .
Active sonar may
pass
through gaps in the
thermal layers without loss.
A submarine cannot use active sonar i f i t s present
current
speed i s abov e 25
knots.
Active
sonar
will be detected a t twice the range to which i t is being beamed;
whatever
the speed of the detec t ing unit. I t i s possible
to
vary the power of
the beam
so
that i t
only
t ravels a
required
distance, up to the maximum of 60
kilometers.
ANECHOIC
TILES
Some
submarines are coated with
Anechoic
Tiles. These are made of rubber, and
absorb active sonar
transmissions,
reducing the
return echo
of
an
act i ve s onar
transmission by 50 .
This means that a submarine
using
i t s active sonar . at 100 power would
radiate
sound waves a ful l 60
kilometers; these
would str ike a t i l e -coated
submarine
a t
that 60 kilometer
range
but
the
t i l es would absorb half of
th
e
sound waves,
so
the return echo would only t ravel 30 kilometers back towards
the searching
submarine. This
means the
target
submarine would remain
undetected, although
i t
would detect the
presence
of a searching submarine,
and
would
gain
a x3
Noise
Multiplier , and bearing.
Effectively,
anechoic
t i l es
halve
the
activ
e
sonar
detection
range, whil
e
doubling
the distance a t
which i t can be heard.
Active sonar cannot be
used
to detec t torpedoes.
Active
sonar may be used
to
map
the sea bed,
or
overhead
i ce. I t may
also
be
used to detect mines. In both cases, i t s effective range is 2
kilometers.
I t
i s
possible to avoid detection
by
active sonar, by hiding i n the s ona r
shadow
cast
by the
sea
bed features (such as
underwater
hi l l s e tc . ) , and
also the shadows cast
by
downward protrusions from
overhead
ice.
Active
Sonar Search Procedure
a) Check the present
depth
of the searching sonar.
b) Plot
the
searching sonars depth on
the
le f t hand edge of the Sonar
Detection Chart.
c)
Plot the
range
and
depth
of
the
potential target .
d) Check
that
the potential
target i s
within
act ive sonar rang
e taking
into
account any layers passed
through.
e) f the
potential
target is
within
range, then i t will
automatically
be
detected, whatever
noise level i t
i s
producing.
f)
On the
chart,
plot out
twice
the prevail ing
detection range
to see i f any
other unit has heard the
radiating
active sonar
waves.
PASSIVE
DUNKING
SONAR SUPHASE
Helicopters with an operable, deployed, dunking sonar may attempt to detect
targets, using
the passive
mode.
Anti-submarine
helicopters
are
normally
f i t ted
with
a
dunking sonar
which
can
be used in ei ther a passive or active mode.
The
helicopter
hovers
above
the
surface
and
lowers
the sonar
down
to the
required
depth. This is done in
the
Sensor Deployment
Subphase
(2.6.5).
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6.8.3
6.9
6.9.1
6.10
The
sonar
works
in
the passive mode
jus t
as for an
in-hull sonar
or towed
array (see
6.5). The maximum detect ion range in th is mode i s 8 kilometers.
ACTIVE DUNKING
SONAR SUBPHASE
Helicopters
with
an
operable,
deployed
dunking sonar may attempt to detect
targets
in the active mode.
The operation of
the sonar i s
as for
6.8,
and the procedure
for
detect ion
is
as for in-hull active
sonar
(see 6.7) . The maximum
range
i s 3 kilometers.
PASSIVE SONOBOUY SUBPHASE
Passive
sonobouys will
attempt
to detect targets.
6.10.1
6.10.2
Sonobouys are carried
by
ai rcraf t and helicopters. For the amount
carried,
see
Aircraft Data
Section 13.0. They
are
dropped in
the
Movement
Phase (see
4.8).
Passive
sonobouys
work in the same manner as a passive in-hull or towed array
sonar
(see 6.5). .
6.10.3
Sonobouys have a passive detection
range
up to 20
kilometers.
The bouy stays
on
the
surface, with an aerial , and lowers a sensor
to
i t s
preset depth
maximum 150m). This depth must be
set
during
the
Command Phase. The sonar
then
works
as
in 6.5.
6.11
6.11.1
6. 2
6.12.1
6.12.2
ACTIVE
SONOBOUY
SUBPHASE
The sonobouy
is
deployed
as in 6.10
above,
and
acts
in
the
same manner
as 1n
hull active sonars (see
6.7).
Active
sonobouys have
a maximum
detection
range of 2
kilometers.
FIXED
SURVEILLANCE
SYSTEM
SUBPHASE
Fixed surveil lance systems will now attempt to detect targets.
In
certain areas,
where i t
i s probable that
submarines may be funnelled, the
U.S and
the
U.S.S.R have laid fixed, passive sonars on the
sea
bed.
One such
system
is
the SOSUS
l ine in the GIUK gap.
These sYstems may be placed no more than 500 kilometers from a continental
shelf or on a
continental
shelf .
They
may act
the same as for in-hull , passive sonars,
but are
not
so accurate
as they can
only place
a submarine within a 100 kilometer ci rc le and i t
is
not
capable of
identifying
the
submarine
type.
6.12.3
6.
3
The
information
is passed
in rea l
time
( ie. immediately),
via a cable to a
ground station.
MAGNETIC NOM LY DETECTION
SUBPHASE
Aircraft
and helicopters
with
an operable M.A.D.
device
will attempt to detect
targets.
6.13.1
Although a Magnetic Anomaly Detector (M.A.D.)
device i s
not a sonar, i t can
detect submerged submarines, and
so
i t has been f i t ted in
here for
simplicity.
6.13.2
M.A.D.
devices are carried
by
Anti-Submarine
Warfare
(A.S.W.)
aircraf t and
helicopters,
usually in a
boom at
the t a i l . Most
submarines are
made
of
s teel , which i s a potentially
magnetic
substance, and therefore such a
large
steel object .will distort the
l ines
of the Earths magnetic
f ie ld.
6.13.3
A
N.A.D
device
is
able
to
detect
minute
variations in
the Earths
magnetic
field, and
so
is able to
detect
the presence of a submarine down to a depth of
300m.
6.13.4 The ai rcraf t or helicopter must be within 1 kilometer (1.5 inches), of
the
submarine,
and
a t
a
height
of no more than 200m. I f i t has been
ordered
to
switch on i t s M.A.D. during the Command Phase, then contact will be made
i f
the
machines
path crosses that made by the submarine this game turn, i t need
not end up over the submarine.
6.13.5 The information gained by a M.A.D.
contact
will be the
point a t
which
the
paths of the machine and the submarine crossed.
No
depth or
type
information
i s
possible.
6.13.6 Some submarines
have
hulls made of
titanium,
which i s non-magnetic. The M.A.D.
device may
only detect these
submarines down
to
a depth of 150m.
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6.14
(It,
SONAR DETECTION EXAMPLE
A Western submarine, a t a
depth
of 260m, is
conducting
a sonar search. There
is
a thermal
layer a t
320m.
t
has
6 potential contacts;-
1) RANGE
is
262
Kin
DEPTII
is
80m.
The target
is in the searching submarines
duct. Western towed
arrays
have
a
maximum
range of 280 Km so
this
target has a possibili ty of
detection by
towed
array;
i t is too distant for in-hull sonar.
2
RANGE
is
204
Kin
DEPTH
is
340m.
This
target
is
in a different duct, but
there is
a direct l ine through the
layer
to
the
target
(check with a rule) .
This
means the target
could
be
detected
by
towed array,
but
is too
distant
for in-hull sonar.
3 RANGE
is
200
Kin
DEPIH
is
600m.
This target
is
impossible to
detect a t the moment. There is no
direct line
through the
layer,
and i t
is
too far
for
active
sonar.
t would be possible
for
the towed array to be lowered below the layer; the target would then be
detectable.
4) RANGE
is
98 Km DEPTH
is
340m.
5)
This
target
is detectable
to
both towed array and in-hull passive sonars,
as
there
is a break in the layer.
s
target
is
not
tecta
e
as there
is
no
break
in
the
layer.
6) RANGE
is
SO Km DEPTH is 60m.
This
target will be
detectable
to towed array, in
hull
passive, and, i f the
searching
submarine
chooses, active
sonar.
Remember, for each chance of detection, percentage dice are rolled. A result
equal to or less than
the radiated noise
from the target,
results
in
detection
.
II
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/
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7.0
7.0.1
7.0.2
7.0.3
7.0.4
and
updates i t s
Phases.
. with information gained
in the
Communications
I t
is
not normally possible for a vessel to launch a weapon a t a target, as
soon
as i t is
f i rs t
detected. The
attacking vessel
must gradually build up an
overall
picture
of what
the
target i s dOing and
may
be about to do. This
picture
is
called the
Target Motion Analysis
(T.M.A.).
In
order to build
up
the T.M.A. the
attacking
vessel must
detect
the target
and keep
i t
detected ,
for
a number
of consecutive game
turns.
Once a
sonar
has
detected
a sound
source,
then
i t will
be
easier
to
re -
detect
i t in
the next game turn.
In
fact, the longer
the
source i s tracked,
then the
easier i t i s
to
retain. This
is
because the sonar
operator i s now
looking for a
particular
sound in a
particular
direction.
In order
to simulate
this
phenomenon
the game art i f ic ial ly amplifies the
noise coming from the target . The
longer
the target is tracked successfully,
the
more the noise i s effectively
amplified,
thus making i t easier to reta i
n.
In order
to in i t ia l ly
acquir
e
the
target ,
then only the actual
noise
level
coming from the target is
used.
Thus EFFECTIVE NOISE GENERATED
(EN ) ACTUAL NOISE
X 1
ie .
there is an effective Noise Modifier (ENM) of xl.
I f
the
f i rs t
turns
search
was
successful,
then
on
the
second
turn of
attempted
contact, there
is
an NM of x 3.
I f the
second
turns search was
successful, then
on the third turn of attempted
contact, there
is
an NM
of x
6.
I f
the third
turns search
was
successful,
then
on
the
fourth turn of
attempted
contact. there is
an
NM of x
9.
I f f or any reason contact i s lost , then the Effective Noise
Multiplier
i s
reduced
by one level; ie. from 9 to 6;
or
from 6 to 3, for each turn
of
failed
contact.
If
the NM was x 3, then th is
is
reduced to x 1.5, for one game turn.
Aft e r th is
the NM
i s x 1, unti l
contact
is
regained.
7.1 Building Up the T.M.A.
7.1.1
7.1.
2
The information to build
up the
T.M.A. comes
in the
following order:-
1st
Turn of
Contact
-
2nd Turn
of
Contact
-
3rd Turn of
Contact
-
4th Turn
of Contact
-
Bearing
from which
noise
i s coming from.
Overall percentage noise
being
generated.
Whether
target
is
probably
a submarine (PROBSUB),
torpedo.
Bearing from which noise
is now
coming.
Overall noise
percentage now
being generated.
Whether
target
i s certainly a submari ne
(CERTSUB).
Current
speed of
target .
Bearing from which noise i s
now
com1ng.
Overall noise percentage
being
generated.
Whether
the target
i s certainly a submarine.
Current speed
of
target.
Current
range to target .
Bearing from which noise is now coming.
Overall noise percentage now being generated.
Type of submarine or torpedo.
Current
speed
of target.
Current
range to target.
Current
depth of
target .
This i s
now a ful l Target Motion Analysis.
If ,
for
any
reason,
the
attacking vessel loses contact
with
the
target
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7.1.3
7.1.4
7.2
7.2.1
7.2.2
7.2.3
usually
by not
throwing
the
required percentage),
then
the
T.M.A.
is
degraded.
If
contact
is lost after
1,2
or
3 consecutive turns
of
successful
contact,
then
the
whole T.M.A.
i s lost .
This means that when
contact is
regained,
the
T.M.A.
will
be
a t
level
1.
I f the
contact
is lost
after
having
had a l l 4 levels
of the
T.M.A. built up
then
2 levels
will
be lost
for each game turn
out
of contact,
providing
the
target has not turned
or
changed depth in any
way this
will
normally only
occur
i f the target is
unaware
i t is being
tracked).
Two Vessel
or Sonobouy
Attack:
i f
two
vessels are
in
direct
communication
with
each
other,
and
both are
independently tracking
the
same target, then
i t i s
possible to
build
up
the
T.M.A.
faster. This is because the
two
vessels
can
trangulate to obtain the
range component without
having
to
wait for
sonar to do i t
1st.
Turn
of Contact
-
Bearing
from which
noise is
coming.
Overall
noise
percentage being generated.
Whether
Prosub or
torpedo.
2nd. Turn
of
Contact -
Bearing
from which
noise is now
coming.
Overall noise percentage
now
being generated.
Whether
Certsub.
Current speed
of target.
Current range to target.
3rd. Turn
of Contact
-
Bearing
from which
noise is now
coming.
Overall noise
percentage
now being generated.
Type of
submarine
or torpedo.
Current speed of target.
Current
range
to target.
Current
depth of target.
In
this
case, the
whole T.M.A. will be lost only
i f both attacking submarines
lose contact
with
the
target,
then treat as for
7.1.3
or
7.1.4.
The above
sequence
of building up the T.M.A. is
always
the case when more than
one sonobouy
is tracking the
target.
7.3 umber of
T.M.A.
Targets
A unit
is
capable
of keeping
a T.M.A. on up
to 6_ targets at
one
time.
Thus
i t
can
be seen
that i t may
take up to 4 consecutive
game turns of successful
contact,
in
order to
be
able to
launch a weapon.
RUBIS SS
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8.0
8.0.1
8.0.2
8.0.3
8.0.4
8.1
8.1.1
8.1.
2
8.1.3
8.1.4
8.1. 5
8.1.
8.1.
7
8.1.8
8.1. 9
8.2
. 2 .1
8.2.2
8.2.3
8.2.4
8.2.5
WEAPONS PHASE
Here,
both
sides may launch or release weapons and sensors
in
order to :
a)
Conduct an
attack.
b) Defend against incoming weapons.
c)
Bring
new sensors
into
play,
for
bet ter
detection.
The major weapon in submarine warfare i s the torpedo. Modern torpedos are a
far cry from the relatively
primitive,
free running torpedoes of the Second
World War. .
Todays
torpedoes are,
in fact highly sophisticated
guided
missiles, capable of
being
steered
by
the parent
vessel, or
of conducting
thei r
own
search
and
attack.
Torpedoes have no towed array.
Note that
submarines s i t t ing
on the sea bed, or are 1n or
against
ice , cannot
launch torpedoes.
WIRE
GUIDANCE
Torpedoes
launched by
vessels
may be guided by
the parent vessel for
a t least
part of
thei r
run,
via a wire
between
the
torpedo
and the vessel. The
wire
will ca r rya l l information from the torpedo
as
well
as
instruct ions from the
controll ing vessel.
Controlling
a torpedo
puts
certain restr ict ions on the
maneouvresthat the
submarine
may
perform:-
a)
The
current
speed
i s
res t r ic ted
to
a
maximum
of
25
knots.
b) Acceleration and decceleration are l imited to 15 of the current
speed.
c) The maximum amount of turn in a Movement Phase is 45 degrees.
d) The
maximum
depth
change
in a Movement Phase i s 100m.
I f
any
of
these maneouvres are exceeded
while guiding
a
torpedo,
then
the
con to 1 wire
will
be severed.
If
the torpedo has not
been programmed when
the
wire i s
cut,
then
i t
will shut
down and
may
be removed from play.
Wire guidance
may
be
used
up to the
maximum
distance,
as
l is ted for that type
of
torpedo see 14.0).
While under wire guidance, a torpedo may make
as many attempts to
acquire a
target , as i t
is brought into
possible detect ion range, before
losing power
af ter covering i t s
maximum distance a t
that
speed sett ing.
A
maximum
of
two
torpedoes
can
be
wire
guided
Simultaneously
and
a
maximum
of
two
targets can
be attacked
a t
the same
time.
Once a wire
guided
torpedo comes into
detection
range of
the target , i t
may be
le t
loose
to
attack
the target on
i t s
own.
This i s
known as an autonomous
attack.
In maneouvring, the torpedo will act largely
as
a submarine. For turning and
changing depth
refer
to the
Turning Table 4.3.4)
and
the
Depth Change By Use
of Hydroplanes Table 4.5.6). The
lateral
movement
los t
will be exactly
as
for
submarines, but reduce a l l noise levels produced,
by
75 .
Torpedoes cannot be
launched at
below
350m
depth.
TORPEDO
SONAR
Torpedo
mounted pass ive sonar has a
maximum detect ion
range of 3 kilometers,
i n
the duct
that
the
torpedo
i s
in.
I ts
passive sonar
may
only
be
used
while
i t is t ravel l ing at OW SPEED.
Torpedo mounted passive
sonar has
no penetration of thermal layers, and
not
even
the
gaps on the
Sonar
Detection Chart.
Torpedo mounted active
sonar
has a detect ion range of 3 kilometers
in
i t s own
duct, and also
in
the ducts
immediately
above and below i t . The active
sonar
will
be heard
at
a range of 6
kilometers
in ALL ducts.
A torpedo may use
i t s
active sonar
a t
any speed.
When a
vessel
is
detected
by the
passive
sonar of a torpedo, the torpedo will
automatically switch to active sonar in order to acquire the target , unless i t
has been
instructed
not to do so.
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8.3
8.3.1
8.3.2
8.3.3
8.4
8.4.1
8.4.2
8.4.3
8.4.4
8.4.5
8.4.6
8.4.7
8.4.8
8.4.9
8.4.10
8.5
8.5.1
8.5.2
B.S.3
TORPEDO LOADING
I t
requires
8
minutes
(4
game
turns) to re-load
a
torpedo
tube.
I t
would
also
take this long to empty a
torpedo
tube.
Due
to space
restricL
iOlls, on I y
Olll'
torpedo tube may
be
re-loaded per submarine
a t
anyone time.
Submarines l i s ted as
capable of ' rapid
re-load' ,
will only
require 4 minllt"s
(2
game
turns)
to re-10ad a tube.
tube may not
be
re-loaded
whilst
the
las t
torpedo launched
from
i l is
sl
i I I
being
wire guided.
PRE LAUNCH WEAPONS PROGRAM SUBPIIASE
Any
weapon
which i s not wire guided,
must be programmed
before launch.
Wt lIpons
which
are wire
guided
may
be progralllliled
a t
any time during t he lorpl'dol's
"LIIl,
usually
when i t is near i t s target .
There are two types of torpedo search pat tern:-
a)
Slow speed; passive.
b) Hi gh speed; active.
When
a
torpedo i s run a t
slow
speed (see 14.0) :
I t
will
use
passive sonar.
The
detection area will
be a
circle
of 7
kilomet
e
rs diamcLcr.(Lh(,re IS 11
need to move
the torpedo
around
i t s circle, jus t
move i L forward
al i Is
slow speed;
the detection
are
.a
will
be a ci rc l e
7 ki
I.ometers a round
i I ) .
The to tal
running time i s
4
minutes. This may
be 4 minutes a t
a
sing/(' depth
or 2 minutes
a t
each of 2 different depths.
When a
torpedo i s run a t
high
speed
(see 14.0) :
I t
will use i t s active sonar.
The detection area this time wi l l be a ci rc le of
10
ki
lom
e t e rs d
jam "
PT .
The
to tal running time will
be
2 minutes,
a l l
at th
e same
depth.
The active sonar waves will be heard 3 kilometers outside the search areil, 1 ( .
13
ki
lometers
from the
torpedo.
The information needed to be programmed into the
torpedo
is : -
a)
Distance
and
bearing to
run
straight out before star t ing
Lhl s
('ar
c h
pattern.
b)
Runout
speed.
c) Type
of
search
pattern.
d)
Depth a t
which
to star t the search pattern.
e)
Whether
to
change
depth during the search
i f
sJow/passjve),
and
if
so
what i s the new depth.
f) Whether
to use sonar
on
the runout,
and
i f
s
o,
when to star t , >lnd
what
type.
Remember,
if the guidance wires are cut before the
torpedo
is
programme
d, then
the torpedo will
shut down.
PROGRAMMING STANDOFF WEAPONS
The
informatioon
needed to be programmed into a standoff weapon 1 S : -
a)
Distance
and
bearing to fly out.
b) I f the payload i s a torpedo: Type of search pattern.
Depth a t which
to star t search p>lttcrn.
Whether
to
change
depth,
i f
so
new
depth.
c) f payload is a nuclear
depth
bomb,
at
what depth i t i s to
explode
.
If
the standoff weapon
i s
a
bal l is t ic missile,
then the
launching
submarine
must
remain
stationary for 10 minutes (5 game
turns),
whilst the missil e (s)
i s /are being
programmed. Normal weapons
may
be programmed
in seconds.
TIIBE CAP SUBPHASE
Both sides
may
open
or
close any
hull
openings to
allow the passage
of weapons
or sensors.
Weapons
being launched
from
submarines will need to
emerge from weapon
tubes.
These tubes
are covered
by
tube
caps, which allow
the tube
to be
re-10adcd
without
flooding the
submarine.
Tube
caps
must be
opened before the
weapon
can
be
fired,
however, opening the
caps
will make
noise (see
6.0.13).
I f caps are l e f t open,
they continue to create noise and
prevent
re-loading.
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8.6
8.6.1
8.6.2
8.6.3
8.6.4
8.6.5
8.6.6
8.6.7
8.6.8
8.6.9
WEAPONS LAUNCH
wea:pons.
In the context of
submarine
combat, a
standoff
weapon
is
one which
travels
through the air
during
part -of i t s D1Qvement to
the
target. This means they
have a relatively
long
range,
allowing the
launching
unit
to standoff from
the target.
Anti-submarine
standoff
weapons launched
by
submarines are usually launched
from
torpedo
tubes. They
then
' r ise to the surface, where a rocket motor
ignites,
propelling
the weapon
towards the target.
When
near the target,
the
payload
will separate
from
the
rocket
', anft
fa l l s
into
the
water,
perhaps
on a
parachute.
The
payload
may be a torpedo; which
will
, begin a
search pattern
in
the
normal
way (programmed before launch);
or may
be a
nuclear
depth bomb. ,
The launch,
surface
ignition and
re-entry into the water,
will
a l l
make
noise
(see
6.0.13).
Launch
is by positive
discharge only. The
minimum
launch depth
for a l l
standoff weapons
is
20m. The 'maximum launch depth for SUBROC and
S S N ~ 1 5
1S
250m.
Maximum
launch depth for SEALANCE and SS-N-16
is
350m.
The
submarine
must be
stationary in order to launch
any
standoff
weapon and
i t is
assumed that the
missile
ignites over
the
launching submarines
position.
The
flight time to the targets position
can be
calculated by dividing the
range
to
the
target,
by
the
missile
'
speed
(in
Km/min). Round up
the
flight
time
to
the
nearest
half minute. This gives the time when the payload enters
the water.
There is
always
the po'ssibi l i ty
that
the standoff we1:lpon will not
land
in
exactly
the right
place.
This
is
especially so in the
case of submarine
launched standoff
weapons. In
order
to simulate this,
the
launching player
rolls a 020, at the Movement Phase when
his
missile
is
due to re-enter
the
water. Use
the score on the
Standoff
Weapon
Deviation
Table
(1) ' following.
STANDOFF WE PON DEVIATION TABLE (1)
DICE SCORE
1-8 1 9 1 10 1 1 12 1 13 J .14 1 15 1 16
I
17
I
18 19 20
.
Deviation
Km)
o
1 1 1 21
4
1
4 I 5 I
6
I
7
I
8
I 9 I
10 1
T21
.
8.6.10 In order to
find the
direction of the deviation,
roll
another
D20, and
consult
Table
(2).
8.6.11
~ ~ ~ : . . . . . . W ~ E A P O N DEVIATION
rection
N
NE
E
SE
8.6.12 f the payload
is
a
torpedo,
on
entering
. the water, it will begin
the
search
pattern
'
i t has
been programmed
for, as
per normal torpedo rules.
If the
payload
is ,a
nuclear depth
bomb. i t
will
sink to
i t s pre-selected depth
and ex
plod
e.
8.
7 TORPEDO LAUNCHSUBPHASE
8.7.1
8.7.2
8.7.3
8.7.4
Both
sides
may launch tor-
pedoes.
There are
two ways of launching torpedoes from submarines.-
a) Positive
Discharge.
b)
Swim out.
Positive Discharge
This method
can
be used to
launch tQrpedoes
while the
submarine has
a
present
speed of up
to
22 knots. I t
is
very noisy.
because the
torpedo
i s
blown out
of i t s
tube
by compressed air
The torpedo may be se,t
to run at
i t s
high
or low speed.
This
is
the
only
way
in
which
standoff
weapons
may
be l.
aunched
and
also,
Soviet Players only. the only way that counter-fire
torpedoes
may be launched.
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8.7.5
8.7.6
8.7.7
8.7.8
8.7.9
8.7.10
8.7.11
Swim
Out
This
method
may
only be
used
for
torpedoes set
to
run at
their slow speed, as
the torpedo swims
out
under
i t s
own power and
is
not ejected. The
only
noise
produced by this method
is
the
torpedoes
own
propulsion
system.
The current speed of the submarine must be lower than the slow running speed
of the
torpedo.
COUNTER FIRE TORPEDOES
This
is
a
tact ic
only
used
by
the Soviets.
I f a
Soviet
submarine detects a torpedo attacking i t i t may
elect
to f ire a
counter-fire torpedo. The
idea
is
to f i re a torpedo down the track of the
incoming torpedo, in
order to hit
the
attacking
submarine, or
at
least
to make
i t maneouvre enough
to lose control of i t s torpedoes).
Counter-fire torpedoes are not wire gUided,
so
they
must be programmed
before
launch. They are
launched
by
positive
discharge
only
and may only run at high
speed.
Before launch the torpedo must be programmed with:-
a)
Search depth.
b) Bearing and
distance
to
run before
conducting an active
sonar search
pattern.
The torpedo must use an active
sonar search
pattern, because i t will
be
launched
on a
bearing-only
T.M.A. and
will
need
active
sonar
to
provide
the
range component.
8.7.12 Counter-fire torpedoes must be l is ted as such at the
s tar t
of the game and
cannot be
used for
any
other purpose.
A
Soviet
submarine
can only carry
a
maximum
of
two such torpedoes.
8.8
8.8.1
8.8.2
8.8.3
8.9
8.9.1
8.10
8.10.1
8.10.2
subphase, units
may
deploy
or retrieve sensors
and
communications
systems.
Submarines
may
begin to
t ra i l
out their
towed
array sonars, i
not
already
deployed
see 6.4
for
restr ict ions caused
by towed arrays). They may also begin
to
retr ieve
towed
arrays in
this phase.
These
may be
je t t isoned at
any time.
Helicopters may deploy
or
retr ieve dunking sonars. I t
is
assumed that these
are
limited
to
a
maximum
depth
of
200m. The
sonar
can
be winched
at
a
rate
of 100m
per minute, so the
time
taken to
get
i t
to
the
required
depth can be
calculated,
and rounded up to the nearest half
minute.
Helicopters must remain stationary while i t s sonar
is
in the water.
Submarines
may release communication bouys expendable
or
not. They may also
t r a i l floating
aerials or
retrieve them. Rules
are
as for towed arrays
see
6.4).
POST LAUHCH WEAPONS PROGRAM SUBPIIASE
Both sides may i f
they wish,
program any wire guided torpedoes which
are
s t i l l being controlled. Rules
are
as
for Pre-Launch
Weapons Program Subphase
see 8.4).
MOBILE
DECOY
PROGR M
SUBPHASE
Mobile decoys may now be programmed ready for launch. They have a
maximum
running time of
18 minutes,
although they
may be programmed
for less.
They move
just
l ike
submarines,
and
will
appear
just
l ike
i t
to passive sonar.
TYPHOON
SSBN
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9.0
9.0.1
9.0.2
9.1
9.1.1
9.1. 2
9.1. 3
9.1.4
9.1.5
9.1.6
9.1.
7
9.2
9.2.1
9.2.2
9.2.3
9.2.4
n t
success or
failure
of
al l
attacks
by weapons
capable of
impacting this turn,
i s
resolved.
During an
attack:-
a) The attacking
player
will
try to raise the Hit Pobability of his
torpedo(s)
to
as
near
to 100
as
possible.
b) The
target player will try
to lower the
Acquisition
Percentage
of
the
torpedo(s)
as
far as he can.
A submarine
that is
unaware of an incoming torpedo
is
less likely
to be
missed.
A submarine
that
is
tracking
an incoming
torpedo,
can
improve
i t s
chances of being missed
by:-
a) Launching
countermeasures,
which will attempt to at tract the torpedo
into attacking them
instead
of
the
submarine.
b) Maneouvring to avoid the torpedo, and also break contact with
the
attacking
submarines'
sonar.
Hit Probability Percentage (HP ), i s a
figure
given to each model of
torpedo,
based on i t s level of sophistication, and
represents
i t s likelihood
of being able to conduct a successful
attack.
I t
i s
l isted for each
type
of
torpedo
in section 14.0.
If
two torpedoes are
launched and
used together
to
conduct
a
simultaneous
attack,
then
a combined
Hit
Probability
Percentage can
be
obtained.
The
attack
will
then
be
prosecuted
as
i f
there
were only one torpedo, but
with
a new
HP .
If
the attack
is
successful, and the two torpedoes acquire the target,
then
they
are treated as two torpedoes again. Only two torpedoes
may
combine their
HP in this way.
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9.3
9.3.1
, 9.3.2
9.3.3
9.3.4
9.3.5
9.3.6
9.3.7
9.3.8
9.3.9
9.3.10
9.4
9.4.
I
9.4.2
9.4.3
9.4.4
DECOY LAUNCH SUBPHASE
There are two types of decoy that a submarine may launch
in
order to lure
incoming
torpedoes
away, and make them attack
the
decoy.
a) Mobile decoys.
b)
Noisemakers.
Mobile Decoys
These are sophisticated devices which
are designed to simulate the
parent
subma