[the.terrabyte.pirate]

Here's my nasty little intercept technique.

1) Pick your targets. I know that my type II has a max speed of 12 knots in fine weather under normal propulsion. Reaching the target has to be achievable. If it's too far away, traveling too fast, or in the wrong direction then it's a lost cause.

2) I start by plotting with the ruler a line from the contact in the exact direction that the contact update states. The contact hardly ever travels exactly along the direction stated (N, NW, ENE etc), but it's a good place to start.

3) Using the protractor I draw a circle with the center on the contact report. If the contact is slow, I'll draw it 6 km radius. If it's medium, 12 km. 6 km represents 6 knots. 12 km represents 12 knots. It's not accurate, but that's irrelevant.

4) Then I do exactly the same for the position of my boat, with a 10 km radius representing 10 knots. This then shows me that in the time it takes me to travel to the edge of the 10 km circle, my target should be approaching the edge of it's circle.

5) I then simply continue to expand the circles by the respective amounts. A slow target's circle would expand to a radius of 12 km, then 18km, then 24 km, while mine expands from 10 km to 20 km, then 30 km etc.

6) Eventually the edge of my circle with intersect with the course of the target. If the edge of my circle intercepts that point before the edge of their circle, it means that I will reach an approx intercept position ahead of them. If their circle has already past that point, it means I either need to either intercept further along it's path, or I need to increase my speed to be at that point earlier. Naturally if the target is traveling medium - fast, chances are that no matter how far along the path I plot an intercept, he'll always be there first. Lost cause.

7) If the intercept is good then navigate to the intercept point at the appropriate speed, submerge, and travel back along his path towards him.

Most of the time I'll pick him up on sonar, and will be in a prime position to attack.

Although the km radius of the circle represents the speed of the target in knots, it is simply a relative measure of distance over time, and not meant to predict an exact time of interception. It only ensures that I'll be there first.