Help with target speed estimation.

[wrrichard]

I must admit I've always played with some ingame targeting help. I am learning full manual targeting now. I have figured out ranging, identification, and AOB. The real hard part for me is target speed estimation. I've read a lot of ways to calculate target speed, but none of them have seemed like a good way for me. I've been using half their max speed for the most part and doing okay, but not great. I'm also getting pretty close before firing.
Do any of you have any thumbrules or quick estimates that you use?

[Chock]

A quick, but not very scientific one is observing the bow wave.

[btaft]

I like HItman's approach of measuring the time it takes for the vessel to pass the same spot in the scope. It is much quicker than the 3 minute rule and is not dependent upon getting a good range reading. Getting close is always a good thing because it minimizes the effect of any inaccuracies in your solution. I would recommend keeping "map contacts on" so that you can check your solution on the attack map to see how good you are getting

Good Luck!

[Hitman]

Thanks for the comment, though I think it would be worth noting that this method has been around for a long time; I did not invent it. My tutorial was just about the methods I use, the only of those I personally "invented" is the aspect ratio determination of the AOB:up: , but germans in WW2 used something similar (Though I learnt about it later:hmm: )

[vindex]

With radar, I measure the distance the ship travels in 6 minutes. Then multiply by 10 and you have your knots/hour. Very convenient, if you have the time to observe.

If you have map contacts on, it's fairly easy to see whether the solution is tracking with the target, and adjust the speed accordingly. I also use the speed to adjust the solution so that it is centered on the target.

[Bilge_Rat]

There are various methods, I use:

1. if the contact was reported by radio, the report includes the speed or speed range;

2. if you have enough time use the 3 minute rule to get an estimated speed;

3. if you are short on time, guestimate a speed, I sually start with 8 kts for merchant/convoys; 15 kts for warships;

4. plug in estimated speed in Position Keeper and refine to final speed;

5. if all else fails, setup for a snapshot as the target crosses you bow.

[zanzo]

Correct me if I'm wrong, boys and girls, but am I the only one who has never had the speed calculation done by the Data Tool? No matter how long I wait after clicking on the Chronometer button in the Data Tool then clicking to send to the TDC the speed is always "00". It doesn't work with the standard game, doesn't work with the 1.02 patch and doesn't work with Real Fleet Boat. It's no great drama to do it with various other methods, but wouldn't it be nice if it worked (for once) just as they explained in the manual?

Can anyone help me/clarify this for me, please?

[daft]

Correct me if I'm wrong, boys and girls, but am I the only one who has never had the speed calculation done by the Data Tool? No matter how long I wait after clicking on the Chronometer button in the Data Tool then clicking to send to the TDC the speed is always "00". It doesn't work with the standard game, doesn't work with the 1.02 patch and doesn't work with Real Fleet Boat. It's no great drama to do it with various other methods, but wouldn't it be nice if it worked (for once) just as they explained in the manual?

Can anyone help me/clarify this for me, please?

The chronometer is broken unfortunately. It's a known bug, and hopefully it'll be fixed in 1.3.

[MaciejK]

There are various methods, I use:

1. if the contact was reported by radio, the report includes the speed or speed range;

2. if you have enough time use the 3 minute rule to get an estimated speed;

3. if you are short on time, guestimate a speed, I sually start with 8 kts for merchant/convoys; 15 kts for warships;

4. plug in estimated speed in Position Keeper and refine to final speed;

5. if all else fails, setup for a snapshot as the target crosses you bow.

Could someone explain the 3 minute rule?

[Bilge_Rat]

3 minute rule, using imperial measures, there are many variations, but this is how I do it:

step #1- identify target, determine range and bearing;

step #2- plot range and bearing on NAV map as Mark #1;

step #3- start chronometer, wait 3 minutes;

step #4- determine new range and bearing;

step #5- plot new range and bearing on NAV map as Mark #2;

step #6- measure distance between Mark #1 and #2 (this requires a bit of a guesstimate, since the ruler only measures tenth of nautical miles)

step #7- multiply distance traveled x 20 = nautical miles per hour ( 1 knot = 1 nautical mile per hour).

The speed estimate is often 10-20% off, but it gives you a trial speed to plug into the PK. Because you are manually plotting the target's course on the map, it also allows you to doublecheck that you have the correct AOB.

ps - you can also use the Nomograph to calculate step #7 - it works very well, I dont use it because I find it clutters up the map, but that is a personal choice.

[DURUK]

There are various methods, I use:

1. if the contact was reported by radio, the report includes the speed or speed range;

2. if you have enough time use the 3 minute rule to get an estimated speed;

3. if you are short on time, guestimate a speed, I sually start with 8 kts for merchant/convoys; 15 kts for warships;

4. plug in estimated speed in Position Keeper and refine to final speed;

5. if all else fails, setup for a snapshot as the target crosses you bow.
Could someone explain the 3 minute rule?

Well.. i really wouldn't like to misguide anyone so i'll leave the explaining of 3 minute rule to someone else.. (i usually mess it somewhere between imperial and metric settings) however i would recommend everyone that has "show contacts on map" enabled the nomograph.. its fast and reliable.. can't understand why not much preffered though..

[mookiemookie]

step #3- start chronometer, wait 3 minutes;


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

[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?

[Bilge_Rat]

step #3- start chronometer, wait 3 minutes;


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


3 min. 15 sec is for meters, 3 min. is for imperial, although since the game screws up meters and yards, you are still right. :o

[btaft]

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)

[Bilge_Rat]

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?

[mookiemookie]

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!

[tedhealy]

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.