TMA and range determination

[TopTorp '92]

Originally Posted by Troels K

Hi

I’m new to Dangerous waters.

I’m having some difficulties determining the correct range to a contact.

At the moment I’m using active sonar to find the range. However, it would be nice if the range could be found without active sonar.

Therefore, how do you guys determine a suitable range to a possible target?

I know the basic TMA like lead/lag course, but the manual says that two or tree legs will result in a single possible solution (page 5-22), these two or tree maneuvers confuses me.

This is probably a huge subject, however, some short guidelines would also be appreciated.

Thanks in advance.

Troels

Let the auto TMA do do the work. Turn the boat 60 degrees every 20 to 30 min or so. Stay in a lag line of sight. Drive behind the target. Shoot. Clear datum. Then do it all over again tomorrow with another target.

Worry not about the complex math. It's too tedious, time intensive and it will warp your sense of judegement. Watch the sonar broadband display for obvious changes in bearing rate and reposition ownship accordingly. Don't forget to stay in a lag LOS. Drive behind the target. Close the range. Shoot. Clear datum . . . and do it all over again tomorrow . . . with a different target.

Keep a snapshot ready just in case one sneaks up on you.

Top Torp