The Tools ] [
The RADAR function in Silent Hunter can be a tricky endeavor, but
with a little basic math and fair amount of practice, you can become
proficient in its use. Regardless of whether you employ the
automatic or manual TDC modes, mastering the RADAR function will add
a whole new dimension to Silent Hunter. Included in this page is a
simple but effective method for utilizing the RADAR. The procedure
described below will work well, but will require course alterations
to insure an intercept. What tends to be confusing about the RADAR
function is the difference between the bearings in degrees relative
to your compass heading and the bearing in degrees relative to your
sub. Gain an understanding of that concept and you're well on your
first, a little background . . . .
RADAR (Radio Detection And Ranging) was
initially installed on US sub's during the latter part of 1941 when
the USS Plunger field tested the first version during an actual war
patrol. It was a rather primitive and unreliable setup called the
SD. Having a limited range (6 - 10 miles), it was non-directional
and primarily useful in detecting enemy aircraft.
major technological improvement came in 1942 with the development of
the SJ RADAR. Designed as a surface search system, it provided exact
range and bearing and redefined many of the tactics (particularly
night surface attacks) employed by the skippers. Further advancement
in RADAR technology came about in 1943 with the PPI (Plan Position
Indicator) or "improved SJ" system. When one commonly thinks of a
RADAR screen, the improved SJ comes to mind. It translates the RADAR
pulse information into a picture, with all bearings relative to the
sub at the center.
Silent Hunter models these system particularly well. The early war
S-boats have no RADAR and thus must rely on gut instinct and visual
sighting. In the career mode, you will receive equipment upgrades as
your patrol dates correspond with the historical use of the improved
major concern of US sub skippers was the fact that prior to the war
Japan had developed a reliable and accurate radio direction finding
(RDF) system in the Pacific. In fact, they were way ahead of the
United States in that category. The Japanese were detecting and
pinpointing US naval vessels well before Pearl Harbor using their
RDF. While the IJN's ability to detect RADAR signals was well known,
it was unclear whether Japanese warships possessed a RADAR system of
their own. In fact, IJN RADAR appears to have been limited to
aircraft carriers and battleships.
Silent Hunter accurately models the SD, the SJ and the PPI RADAR
systems used by US submarines during WWII. The graphic below is of
the PPI. The actual screen controls will vary from system to system
as historical improvements and advances were made depending on the
year you are in.
Toggles between on/off, PPI and A scope.
2) Allows you
to toggle between "rotate" and "focus". It can lock on to a
contact to determine bearing and range.
3) SD on/off.
4) Allows you
to adjust the range scale. Particularly useful in PPI when
making a night surface approach, or executing an intercept
5) Range to
method allows you to turn "bow on" to a contact bearing.
assume for this exercise that your sub has a heading of 030. This
heading is in terms of a compass bearing. With due North being 0
degrees, this means that you are traveling in a direction 30 degrees
relative to due north.
let's assume that the picture on the right is your RADAR screen.
While it looks exactly like a compass in the graphic, the difference
is that the RADAR bearings are relative to your sub and not to
North. Your bow would be 0 degrees, your starboard (right side) beam
would be 90 degrees. The stern is at 180 degrees and 270 off the
port (left side) beam.
graphic shows a RADAR contact at a bearing of 240. Now you need to
figure out what heading to take to try to intercept the contact.
Here's what we know:
sub was at a compass heading of 030.
B) RADAR picked up an unknown contact bearing 240 from the sub.
find the correct course heading to take, add the two figures.
240 + 030 = 270
turning the sub's bow in the RADAR graphic to 30 degrees, and laying
it over the compass image you can see that the RADAR contact pip
lines up with 270 degrees on the compass.
. . . suppose you are on a course heading of 240 degrees and RADAR
reports a contact bearing 311 . . . .
+ 311 = 551
Obviously this needs to be adjusted because there are only 360
degrees in a compass circle. In this situation simply subtract 360
from the figure.
+ 311) - 360 = 191
correct "bow on" heading course would be 191. Hit the F7 key to take
you to the gauges screen, or the F4 key to take you to the bridge.
Find 191 on the compass and click. You are now on your way and have
completed the first step in conducting a successful contact
Compass heading bearings are relative to due North.
Radar bearings are relative to your submarine, with your bow being
at 0 degrees, regardless of your actual direction of travel.
Adding your course heading to the RADAR contact bearing (or
subtracting 360 as necessary) will put you in a direction to
intercept the contact.
that you have determined the bearing, range and probable location of
the contact and you have initiated a course change to execute an
intercept, you will need to monitor the RADAR screen until you can
make a visual sighting. The above model turns you in the direction
of the contact. Unless the ships are anchored in port, the bearing
and ranges will change constantly as the ships continue their
transit. You will need to order additional course changes to adjust
for their movement. If you are in the period that has the PPI, lock
on to the closest contact and take a look at the range dial. See if
the range is increasing, meaning they are heading away or
decreasing. A convoy at too great a range may be impossible to catch
if they are heading away from you.
you begin to close the distance between your sub and the approaching
targets, change the range ring settings to give you a clearer
picture of what the convoy looks like. The larger "blips" are your
bigger targets. You will also be able to locate the escorts too;
found usually hanging around the perimeter of the group. Don't be
confused by the super large blips . . . it's probably interference
from a land mass, but you can check your charts just to be sure. As
you gain experience and confidence in reading the RADAR screen
you'll be able to alter your course well in advance of the convoy
for the best possible attack position. I have found that by keeping
the oncoming targets bearing in the neighborhood of somewhere
between 315º and 45º I can generally work into a fairly good set up.
One method that
navies use to reduce the threat from a submarine attack is the "zig
zag". You can see the challenge of trying to determine the exact
heading or target solution when your contact changes course so
often. Obviously, this can be particularly frustrating when you are
on a final attack approach and the target zigs away just before you
were ready to fire your torpedoes.
Tracking a zig
zagging convoy can try one's patience, but it is most certainly
"do-able" with RADAR. For those who want to duplicate the methods
used by WWII skippers, you can come to a full stop and note the
bearing info from your RADAR screen. Doing this several times, and
plotting the course will give you a pretty good picture of their
actual heading. Make sure to change the range ring settings (arrow 4
in the Tools graphic) as you begin to cut the distance
between your sub and the convoy.
inexpensive and reusable plotting board can be made by simply taking
a piece of 8½ x 11 sheet of paper and drawing a large circle. Find
the center and place a large dot. Now, around the outer edges of the
circle pencil in the compass bearings from 0 to 350°. You can
actually make it in 5 or 10 degree increments. Obviously the smaller
the increment the more accurate your data will be. You can insert
the copy into a clear plastic presentation page cover and use an dry
erase marker or grease pencil to add the contact points.
A "cheat" method of
countering the zig zag is to turn your sub "bow on" to the contact
and increase your time compression so that you have virtually a
constant picture of the convoy's movements. Adjust your course
gradually using the arrow shortcuts to keep them on track.