Help with target speed estimation.

[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 , 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.

[MaciejK]

Originally Posted by 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.

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.

[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.

[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]

Originally Posted by mookiemookie

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

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.

[DURUK]

Originally Posted by MaciejK

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..