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Pisces · 08-30-09, 04:44 AM

Here is a classic tutorial on how it can be done with SH3:

http://www.subsim.com/radioroom/showthread.php?t=88961

(whoops, the same technique as that wiki link)

Look for post 41 on the second page. A good summary picture of the procedure. Allways make these kind of drawings based on where the contact should be right now!. Especially if the contact report is hours old.

Allways go as fast as you can, top-speed, or flank if fuel is not an issue. But readjust the drawing if weather is slowing you down. Then the contact has the least amount of time to move away and the search area stays limited in size.

As for how far away you can depends on experience, the capabilities of your boat, and on the situation. Knowing his speed accurately is most important for long range intercepts. But if you got just a speedrange it's wise to use a worst-case speed. Then you'll allways end up infront of it, and can turn to meet the contact along it's course if it isn't there. Also meet him at top speed since you can loose it if it makes a course, or speed, change in the meanwhile. If you can't find him at all, though luck, but you did your best.

Whenever you arrive at the intercept location, and the contact actually did have the assumed speed, the target may still be outside of visual range due to it having a course slightly off from the reported course. So you will have to rely on radar or hydrophone (sonar is too short) to extend your detectionrange. The reported course (N,NNE,NE,ENE,E, etc. ) are all in steps of 22.5 degrees, which means that the actual course can be 11.25 degrees on either side of reported. You need to fit your best sensor range (circle) within such a 22.5 degree wedge to determine how far you can let the contact move (since time-stamp of contact report) before he might sneak past undetected on the fringes of detection range. Roughly speaking this is 5 times your maximum detection radius. So if your radar has a range of 30nm (60k yds) make sure you can be at the intercept point before he has moved 150nm or don't bother to intercept at all. Beyond that his chances of of a lucky undetected escape increases.

To make that visual: Draw a courseline for the contact of 5-times-sensor-range from it's origin point. Draw a circle centered at the end of the line with a radius the same as your best sensor. Draw another 2 lines starting from the contact origin point with the ends touching on either side of the circle. You should get a drawing that looks like an ice-cone. If your intercept course doesn't intersect it before the center of the circle you should forget about it.

The above drawing also solves the issue of whether or not to intercept a contact that is allready moving away from you. If the intercept drawing (with the ice-cone) says you can get it in time, don't second guess it, but GO FOR IT.

08-30-09, 04:44 AM	#6
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	Here is a classic tutorial on how it can be done with SH3: http://www.subsim.com/radioroom/showthread.php?t=88961 (whoops, the same technique as that wiki link) Look for post 41 on the second page. A good summary picture of the procedure. Allways make these kind of drawings based on where the contact should be right now!. Especially if the contact report is hours old. Allways go as fast as you can, top-speed, or flank if fuel is not an issue. But readjust the drawing if weather is slowing you down. Then the contact has the least amount of time to move away and the search area stays limited in size. As for how far away you can depends on experience, the capabilities of your boat, and on the situation. Knowing his speed accurately is most important for long range intercepts. But if you got just a speedrange it's wise to use a worst-case speed. Then you'll allways end up infront of it, and can turn to meet the contact along it's course if it isn't there. Also meet him at top speed since you can loose it if it makes a course, or speed, change in the meanwhile. If you can't find him at all, though luck, but you did your best. Whenever you arrive at the intercept location, and the contact actually did have the assumed speed, the target may still be outside of visual range due to it having a course slightly off from the reported course. So you will have to rely on radar or hydrophone (sonar is too short) to extend your detectionrange. The reported course (N,NNE,NE,ENE,E, etc. ) are all in steps of 22.5 degrees, which means that the actual course can be 11.25 degrees on either side of reported. You need to fit your best sensor range (circle) within such a 22.5 degree wedge to determine how far you can let the contact move (since time-stamp of contact report) before he might sneak past undetected on the fringes of detection range. Roughly speaking this is 5 times your maximum detection radius. So if your radar has a range of 30nm (60k yds) make sure you can be at the intercept point before he has moved 150nm or don't bother to intercept at all. Beyond that his chances of of a lucky undetected escape increases. To make that visual: Draw a courseline for the contact of 5-times-sensor-range from it's origin point. Draw a circle centered at the end of the line with a radius the same as your best sensor. Draw another 2 lines starting from the contact origin point with the ends touching on either side of the circle. You should get a drawing that looks like an ice-cone. If your intercept course doesn't intersect it before the center of the circle you should forget about it. The above drawing also solves the issue of whether or not to intercept a contact that is allready moving away from you. If the intercept drawing (with the ice-cone) says you can get it in time, don't second guess it, but GO FOR IT. __________________ My site downloads: https://ricojansen.nl/downloads Last edited by Pisces; 08-30-09 at 05:06 AM.