Cpt_Geschraub

04-10-2005, 10:54 AM

So I have been playing SH3 for a week or two now and one thing that really gets me is intercepting those radio contacts. I'm sick and tired of taking my compass and drawing little circles around my ship and the contact and trying to figure out where I should intercept the contact. Which, Of course, doesn't work all the time and leaves me cursing as I sail in circles trying to find the ship. So I thought, hey, there has to be a formula to calulate these things. So I grab my calculator and a hour of trigonometry later I figure out the formula. Here's how to intercept radio contacts using Cpt.Geschraubt's interception formula.

You need: a TI graphing calculator or something that can evaluate sines and inverse sines. If you don't have one go here (http://www.calculator.com/calcs/calc_sci.html)

First, you receive the contact's position via radio. Here is a ship going at a slow speed.

http://img86.exs.cx/img86/4778/16lh.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=16lh.jpg)

Next, you draw a straight line ahead of the contact going the same direction. This is the contact's projected path.

http://img86.exs.cx/img86/8728/26oa.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=26oa.jpg)

Then you draw a straight line from your sub directly to the contact.

http://img86.exs.cx/img86/1832/34bl.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=34bl.jpg)

Use your protractor to measure the angle between the two lines. The angle here is 123 degrees.

http://img86.exs.cx/img86/581/42el.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=42el.jpg)

now use this formula to calculate the angle you need to turn from to intercept the contact. You should use knots as the the u-boat and ship's speeds.

http://img163.exs.cx/img163/8044/form3nl.jpg

My u-boat is traveling at 12 knots and the contact is traveling at approximately 5 knots.

http://img158.echo.cx/img158/2964/form28ww.jpg

And so the angle I need to turn to intercept the ship is 20.4534 degrees

measure the angle out

http://img51.exs.cx/img51/1120/50ov.th.jpg (http://img51.exs.cx/my.php?loc=img51&image=50ov.jpg)

and plot the point.

http://img51.exs.cx/img51/4011/60jv.th.jpg (http://img51.exs.cx/my.php?loc=img51&image=60jv.jpg)

make sure when you plot your course you plot it a little ahead of your point so you will end up in front of your target therefore you will have the perfect Opportunity to set up an ambush.

http://img51.exs.cx/img51/4686/76dj.th.jpg (http://img51.exs.cx/my.php?loc=img51&image=76dj.jpg)

With a little luck, you will spot the ship in no time.

http://img56.exs.cx/img56/3255/87on.th.jpg (http://img56.exs.cx/my.php?loc=img56&image=87on.jpg)

Note that this formula won't work well in bad weather because it's not 100% accurate and

visibility is very poor on dark and stormy nights. (trust me, I pulled up 5 meters beside a

c2 cargo before my crew finally spotted it.)

Also note that the accuracy of the formula decreases the further you are away from the target so I recommend you use this for 150km or less. Happy hunting!

You need: a TI graphing calculator or something that can evaluate sines and inverse sines. If you don't have one go here (http://www.calculator.com/calcs/calc_sci.html)

First, you receive the contact's position via radio. Here is a ship going at a slow speed.

http://img86.exs.cx/img86/4778/16lh.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=16lh.jpg)

Next, you draw a straight line ahead of the contact going the same direction. This is the contact's projected path.

http://img86.exs.cx/img86/8728/26oa.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=26oa.jpg)

Then you draw a straight line from your sub directly to the contact.

http://img86.exs.cx/img86/1832/34bl.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=34bl.jpg)

Use your protractor to measure the angle between the two lines. The angle here is 123 degrees.

http://img86.exs.cx/img86/581/42el.th.jpg (http://img86.exs.cx/my.php?loc=img86&image=42el.jpg)

now use this formula to calculate the angle you need to turn from to intercept the contact. You should use knots as the the u-boat and ship's speeds.

http://img163.exs.cx/img163/8044/form3nl.jpg

My u-boat is traveling at 12 knots and the contact is traveling at approximately 5 knots.

http://img158.echo.cx/img158/2964/form28ww.jpg

And so the angle I need to turn to intercept the ship is 20.4534 degrees

measure the angle out

http://img51.exs.cx/img51/1120/50ov.th.jpg (http://img51.exs.cx/my.php?loc=img51&image=50ov.jpg)

and plot the point.

http://img51.exs.cx/img51/4011/60jv.th.jpg (http://img51.exs.cx/my.php?loc=img51&image=60jv.jpg)

make sure when you plot your course you plot it a little ahead of your point so you will end up in front of your target therefore you will have the perfect Opportunity to set up an ambush.

http://img51.exs.cx/img51/4686/76dj.th.jpg (http://img51.exs.cx/my.php?loc=img51&image=76dj.jpg)

With a little luck, you will spot the ship in no time.

http://img56.exs.cx/img56/3255/87on.th.jpg (http://img56.exs.cx/my.php?loc=img56&image=87on.jpg)

Note that this formula won't work well in bad weather because it's not 100% accurate and

visibility is very poor on dark and stormy nights. (trust me, I pulled up 5 meters beside a

c2 cargo before my crew finally spotted it.)

Also note that the accuracy of the formula decreases the further you are away from the target so I recommend you use this for 150km or less. Happy hunting!