User Guide

UNDER ICE DISPLAY
All controllable subs in Sub Command are capable of operating and surfacing when under the ice.
The basic under-ice operating procedures are the same regardless of the submarine class you are
commanding and are covered in Special Operations and Procedures/Under Ice Operations on p.
152.The use of the Under Ice Display to locate polynyas is covered here.
In order to surface when under the ice it is necessary to locate an area of thin ice or open water
called a polynya. In Sub Command, each class of submarine uses different equipment to locate an
appropriate place to surface.These are covered separately below.
In Sub Command, all controllable submarines are given equal under ice capabilities. No one hull is
stronger than another. Surfacing or attempting to surface in ice that is too thick can cause damage
to your ship.
ICE THICKNESS DAMAGE
0-4 feet: No Damage to Ownship.
4-8 feet: Minor damage (May lose ice sensors).
8-12 feet: Moderate damage. May lose masts.
> 12 feet: Flooding possible.
SEAWOLF: UNDER ICE DISPLAY
The Seawolf’s Under Ice Display is incorporated into the ship’s Trim Display in the Ship Control
Station.A profile of the ice thickness above Ownship is represented across the top of the Trim
Display. If you change your course, the display instantly updates to display the ice thickness on the
new course.
688(I): UNDER ICE DISPLAY
The 688(I) utilizes an upward looking television camera to assist in locating suitable locations for
surfacing when under the ice. Suitable areas appear brighter while areas where the ice is very
thick appear dark. Because the TV relies on differences in brightness it is not helpful at night.The
Signal Strength Indicator uses colored lights to indicate the thickness of ice directly over Ownship
as follows.
Green: 0-4 feet thick
Yellow: 4- 8 feet thick
Red: 8- 12 feet or more.
AKULA: UNDER ICE DISPLAY
The Akula’s High Frequency Display utilizes an upward looking High Frequency Acoustic Sensor and
a Signal Strength Indicator to help determine ice thickness. In Upward Looking mode,the display
window red indicates ice and black indicates no ice.The display is never a solid red when ice is
present but has a mottled look displaying various shades of red.The darker areas are locations of
thinner ice.The representation of ice at the center of the display indicates the ice directly over
Ownship.
The row of colored lights beneath the display window is the Signal Strength Indicator. The strength
of the signal returning from your acoustic Sensor indicates the thickness of the ice directly above
Ownship. Signal strength is represented as a color indicating ice thickness as shown below.
145
Sub Com PC elec manual.qxd 7/25/01 4:59 PM Page 145