manual targeting - speed

Frederf · 08-23-09, 11:37 PM

Many of us don't consider the stopwatch button on the speed TDC input dial "manual targeting." Either way, it's a simple script that takes 2 bearing-range inputs and calculates a course and speed required to go from one to the other in the time between the two sightings. Being automated computer code it is very inflexible and intolerant of anything but exactly the behavior it expects.

Each of the two readings has to be of the stadimeter/bearing type where you use the stadimeter with the periscope wire on the target and click the "Update bearing" button. After you have done this twice with the correct time between (I think it has to be >10sec and <1hr but 30sec to 10 minutes is normal use).

The function only uses the last two readings. If you click the send button twice to fix the little visual bug where the torpedo red arrows don't update... that counts and you'll have to start again.

Now as far as accuracy in concerned there are all sorts of problems with the target speed-course helper function. I don't think it accounts for your own submarine's motion so if you move between sightings there will be inaccuracy. I think it does compensate for changes of own sub heading between readings but I'm not sure.

If you make a mistake on the 2nd reading the 1st reading is effectively lost and you have to start all over again. With manual plotting of bearings you can average out many readings to get a better or more confident result, which you cannot do with the helper. With manual plotting you can run the PK function while you are doing the process but with the helper you have to have PK off. Basically while you're doing the helper function the TDC is all tied up.

08-23-09, 11:37 PM	#4
Frederf Seasoned Skipper Join Date: Apr 2005 Posts: 665 Downloads: 79 Uploads: 1	Many of us don't consider the stopwatch button on the speed TDC input dial "manual targeting." Either way, it's a simple script that takes 2 bearing-range inputs and calculates a course and speed required to go from one to the other in the time between the two sightings. Being automated computer code it is very inflexible and intolerant of anything but exactly the behavior it expects. Each of the two readings has to be of the stadimeter/bearing type where you use the stadimeter with the periscope wire on the target and click the "Update bearing" button. After you have done this twice with the correct time between (I think it has to be >10sec and <1hr but 30sec to 10 minutes is normal use). The function only uses the last two readings. If you click the send button twice to fix the little visual bug where the torpedo red arrows don't update... that counts and you'll have to start again. Now as far as accuracy in concerned there are all sorts of problems with the target speed-course helper function. I don't think it accounts for your own submarine's motion so if you move between sightings there will be inaccuracy. I think it does compensate for changes of own sub heading between readings but I'm not sure. If you make a mistake on the 2nd reading the 1st reading is effectively lost and you have to start all over again. With manual plotting of bearings you can average out many readings to get a better or more confident result, which you cannot do with the helper. With manual plotting you can run the PK function while you are doing the process but with the helper you have to have PK off. Basically while you're doing the helper function the TDC is all tied up.