TDC Issues

[cwelt]

Originally Posted by Rockin Robbins

You have several overlapping problems here. Firstly, you are activating the PK way after the data in the TDC is stale. You are developing data in the wrong order. Using the stadimeterto get a speed/course estimate is so innacurate that it should be a last resort option. And you are shooting after you have determined you are wasting a torpedo. Let's fix it.

1. Use radar fixes to calculate speed. Measure the number of yards between 2 fixes three minutes apart. Divide by 100 (drop two zeroes or slide the decimal two places left) to get kph: 700 yards equals seven knots. Enter that into the TDC. Since this parameter doesn't change continuously, you can do this before your turn on the PK.

2. Turn on the PK. All other parameters will continuously update as your own boat and the target move.

3. Set AoB to match unit's course. Now if you change course and speed the target will remain in your crosshairs and course craziness will not occur unless the target changes its course.

4. Lock the periscope to the target. Use the stadimeter and press the send range/bearing button to get the data to the TDC. Your PK is now locked onto the target and if his course and speed remain unchanged AND if your inputs are correct you can shoot any time the target is in range.

5. Switch to the attack map and watch your impact point. It should be superimposed on the target and follow it long enough for a torpedo to travel from its tube to impact point. It is quite easy to see when a change in AoB or target speed is necessary. Just tweak those parameters, repeat step 4, and check again.

6. Don't shoot until your attack map shows the impact point stays on the target long enough for the torpedo to get there. Did you open the torpedo door? If not, open it now, giving plenty of time for the door to fully open.

7. The last thing to do is update the range and bearing just before you shoot.

At any time during the procedure, you can lower and raise the periscope as necessary or desired. Tube opening is not critical so long as the tube is fully opened at time of firing.

Thanks very much, I figured something I was doing was wrong... your step by step seems alot more fluid than mine did. I will test this out tonight and be sure it is working. I hope you just saved the USN a ton of money in wasted torps