SUBSIM Radio Room Forums - Help with target speed estimation.

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- - Help with target speed estimation. (https://www.subsim.com/radioroom/showthread.php?t=114593)

Quote:

Originally Posted by raduz

interesting... nobody speaks about the hydrophone turn count to determine the targets speed... I wonder why... did they never use it during the war?

You could do it in SH3, for example http://www.subsim.com/radioroom/showthread.php?t=107303

Does it work in SH4?

Quote:

Originally Posted by btaft

Quote:

Originally Posted by Bilge_Rat

step #3- start chronometer, wait 3 minutes;

Not to nitpick, but It's actually 3 minutes and 15 seconds. :know:

Actually it is correct as described above for imperial units.....3 minutes x 20 (60 minutes in an hour) since the map displays values in nm and this would be the distant traveled in 1 hour.

If using metric units then the 3:15 is value used since you are converting from meters to knots and not multiplying by anything (i.e. the distance measured for a period of 3:15 turns out to be the speed in knots.....just ahppens to work out that way)

Well heck, I figured it worked in SH3, it should work in SH4!

No wonder we never adopted the metric system! :doh: Thanks for the correction!

Playing with map contacts off, first I make two plots on the map from bearing and range so I can get a rough idea of course and AOB. As I get closer, I refine this and tinker with AOB.

I guesstimate the speed based on the bow wake, ship type, and max top speed from the ID chart. I plug that into the TDC with the other info, then watch the PK's generated bearing. If at scope depth, I make visual checks on the target every 1 to 5 minutes, if the PK's generated bearing gets out in front of the actual bearing, I reduce the speed on the TDC. If the generated bearing falls behind the actual bearing, I increase the speed on the TDC. I then repeat the process making adjustments to speed (and AOB too if it's way off as this could throw the generated bearing off) until the generated bearing can match the actual bearing for at least a minute or two. I try to get the bearings to match for longer, but usually a minute or two is good enough for a short range torpedo run.