Construction of CapnScurvy's Angle on Bow Calculator
January 7, 2008
This calculator has three parts, pages 5, 6, 7 or 8 (page 7 is for imperial use, page
8 is for metric). The pages should be printed, cut out, and held together with a
two prong, brass brad fastener. Your printer should be set to its highest printing
preference, and you should use standard 8.5 x 11 heavy weight card stock paper
(110 lb is good). Click on the printer icon at the top of this PDF screen, a PDF
"Print Box" will appear. About half way down find the heading "Page Handling",
find the item "Page Scaling" and enter "Fit to printer margins" if its not displayed.
This will insure a correct page size for the calculator parts. Be careful to have the
three parts lined up correctly when you are making the center whole thru the
Once constructed, use the document included in this PDF (pages 2, 3, and 4) to
learn how to use the calculator with Silent Hunter 4 Wolves of the Pacific. This
basic instruction will be good for gamers using the game play elements set to a
medium low realism, (i.e. Only the "Manual Targeting System" enabled (check
marked) within the game options. The other options except for "No Map Contact
Update" can be set to whatever preference you like. The "No Map Contact Update"
option should be considered when you are ready for a much more challenging
Another tutorial is available for using the calculator with high realism game play
settings enabled in Silent Hunter 4. This "High Realism Tutorial" will show you how
to use the calculator and other tools of the game to find target ship positions and
headings when both "Manual Targeting System and No Map Contact Update" are
enabled (check marked) in the game play options. You will learn to plot target ship
courses, find AoB, and time for speed, all from the Navigation Map. This will
enable you to plan attacks based on the data you acquire manually. With the 1.4
patch came the ability to measure in 50 unit increments (yards or meters) rather
than tenths of nautical miles (202 yards) on the Navigation Map. This will create
much greater accuracy when manually plotting a targets course.
See you under the sea.
CapnScurvy's Angle on Bow Calculator
Jan. 7, 2008
The three parts of the calculator are from largest to smallest:
1 . The Base Wheel
The blue Arrow along the bottom represents your sub's course heading to the middle Compass Dial. The outer numbers in
the blue field, represent your view-to-target bearing that can be found at the top of the Binoculars, Periscope, or UZO.
2. The Compass Dial
3. The Target AoB Dial
The black arrow represents the target ship's course heading to the middle Compass Dial. The outer smaller numbers are the
Angle on Bow indicators. Angle on Bow is the direction bearing of your sub from the target ship's bow, either Port (left) or
You will need to know three things to make a correct calculation. They are:
1 . Course heading of the target ship
2. Your own boat's course heading
3. The view-to-target bearing
For this basic instruction, have the game play options of "Manual Targeting System" enabled (check marked) and the "No
Map Contact Update" disabled (unchecked). To find the target ship course heading, use the Navigation Map to plot its
course. Along the left side of the map, open the Compass by clicking on it, next click the Ruler. This will give you the
Bearing-to-North Protractor tool. Click and drag a line through the target ship in the direction of its travel and read the
bearing that the line intersects with along the BACK edge (closest to the target ship) of the protractor.
The Orange circle shows
the Compass icon clicked
"open". This changes the
ruler into the Bearing to
North Protractor. The Green
circle indicates where you
read the bearing heading
for the target ship. In this
example it's about 112'.
Your sub's course heading can be read from the Compass of the Quick Controls Panel along the lower
portion of the game screen. As long as you both keep a steady course, the calculation will be accurate
until a course change is made by you or the target ship.
The Yellow circle on the
left picture shows your
compass dial. The small
red arrow points to the top
center of the dial indicating
the subs course bearing.
There are no indicator
marks along the rim of the
compass to help in its
reading. A mod compass
would be nice to add if it
has larger bearing
numbers with indicator
Your sub's course heading
can also be obtained the
same way as the target ship
by centering the Bearing to
North Protractor over your
sub's projected path line and
reading the value closest to
the sub. In this example it's
To obtain the view-to-target
bearing or just "target bearing" use
either the periscope, UZO, or the
binoculars to site the target. The
bearing of the target, from your
sub, will be seen at the top of the
device. In this example the view-
to-target bearing is about 328'.
Now we have the three pieces of
information to make a calculation.
Target course bearing=1 12'
Sub course bearing=305'
View to target bearing=328'
Using the illustration below, line
up the black Arrow of the inner
Target AoB dial with it's course
heading of 1 12' onto the Compass
Dial (the Green circle). Next, while
moving the two smaller dials
together, line up the Base Wheel's
blue Arrow to your boat's course
heading of 305' with the Compass
Dial (the Red circle). Now find the
"view-to-target bearing" of 328'
along the outer Base Wheel and match it with the inner dial's Angle on Bow degree numbers (the Blue arrow along the lower
right, drawn to the inner dial at about the 2 Port mark). The AoB bearing is about 20' Port.
The AoB will change with the
movement of both ships, so keeping
the blue Base Wheel "view-to-target
bearing" moving with the target ship is
a good idea. "Locking" the in-game
view is advised, however you should
use caution regarding leaving your
periscope up for too long. There is a
chance of being spotted, causing the
target to take evasive action. No
need to move the dials unless a
course change occurs between the
You can also get AoB info for future
firings by using the navigation map to
draw out your subs future planned
course heading. As long as the target
dosn't change course, you will not
need to move the inner dial. By
moving the blue Arrow to your new
course, you will see what the future
AoB will be.
Happy Hunting !
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Time Target Ship
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Time Target Ship