Destroyer Circle Radiuses
 

After identifying a destroyer, if you select it on the map, four circles highlight around it.
One looks like a 3/4 circle tight around the ship in the shape of a pac man, mouth out the rear.
The second is a semi circle further out from midship to mid ship facing the bow.
The last two are around the whole ship about 10nm out with one slightly smaller.


I assume one is radar and one sonar but I dont know what the other two are and I dont know which is which.


Anyone know?

The smallest is active sonar (ping), the 2nd would be passive sonar, the 3rd visual, the 4th radar... usually maybe - because mods might change them... There used to be an illustration in the Silent Hunter Manual - I think... might have been a dream... :O: - but I do know that somewhere on the site here is a rather good description of it, but I wouldn't have a clue what to "search" on to find it (them)... :salute:

Thanks, exactly what I was looking for.

Worst trouble with doing a search is I find the old threads - and the pictures are gone. Basically the circles, half and "pie wedge" circle represent the AVERAGE detection zones for different sensors.

https://scontent-msp1-1.xx.fbcdn.net...87&oe=5DF7B723

First number is max range, second number is average range. If you're near the outer circle an elite crew has a good chance of detecting you on radar, inside the circle a competent (average) crew will probably detect you. No way to know how good the enemy crew is unless you know which escort it is from the mission editor, but basically either the radar or visual ranges it's a good idea to submerge before going inside those. Early war you won't see a radar circle, late war you might see a passive sonar circle on some merchant ships.

Passive sonar is hydrophone, which is an underwater microphone that can hear whatever noise the sub is making - running at standard or higher speed, loading torpedoes, throwing wrenches at the cook because the coffee is cold, all those can be heard on the hydrophone if you're within range. The reason for the wedge cut out of the back is the "baffles" - the destroyer's own propellers make too much noise to hear any other sound in that wedge.

Active sonar is the ping pong, transmit a ping and if there's a big solid object in the half circle there's a good chance the ping will echo off the object and give a range and bearing. Two ways to beat that, aspect and thermal layers. Aspect means if the destroyer is on your beam, he has a big target to bounce pings off of, if you're facing directly toward or away from him it's a narrower target he has less chance of getting an echo from. Thermal layer is when the temperature of the water makes a sudden large change, when you hear "passing thermal layer" note the depth and go 60 feet lower to get the whole sub under the layer.

Gonna post the pic again with a different format, I don't know why this forum keeps erasing them.

https://scontent-msp1-1.xx.fbcdn.net...87&oe=5DF7B723

Excellent, Sniper297! I just thought I hadn't found the thread yesterday because there weren't any pix on it... I don't know if I could find that again... :salute:

Great Info.:Kaleun_Cheers: