Multiple Sonar Lines

[Doenitz2008]

How do you more experienced skippers do it ? I'm talking about a sonar only approach to a large formation. I'm trying to attack a large TF headed to Rabaul, July 1942. Conditions dictate sonar approach, with a few periscope peeks. I note that the only options really in terms of following a single contact are 1) follow nearest warship, or 2) follow nearest contact.

I'm trying to focus on a specific contact in order to determine speed. I'm finding this very difficult with 9 or 10 sonar lines extending out from my sub, some of which are only 2-3 degrees apart.

And - how accurate are the sonar lines for marking positions? I.E., my sonar man tells me merchant bearing 320. I ping at 320, get a range. When I use the compass to mark bearing and range, is the sonar line that extends from the sub a close enough indicator to the 320 mark ?

Thanks

PS: How do you read and interpret A-Scope radar ?

[commandosolo2009]

I'm trying to focus on a specific contact in order to determine speed. I'm finding this very difficult with 9 or 10 sonar lines extending out from my sub, some of which are only 2-3 degrees apart.

This is meant to simulate a non-aware convoy. In real life, skippers had to deal with everchanging courses convoys, zigzagging packs, and non AI tincan openers.. The normal approach is to yo-yo the periscope just to get a general bearing, and if desired, target speed (although you play with contacts on, you dont have to, since you can calculate based on point A to point B / time in secs to get speed and course, now whats left is the range thru pings ((least preferred or fail-safe versus already inaccurate stadimeter)) and of course the firing bearing which you decide based on target behaviour)

And - how accurate are the sonar lines for marking positions? I.E., my sonar man tells me merchant bearing 320. I ping at 320, get a range. When I use the compass to mark bearing and range, is the sonar line that extends from the sub a close enough indicator to the 320 mark ?

Sonar lines are arbitrary even if you manage to get a hold of their last pixel, you definitely have to break waterline for a final look and with contacts on, you can see their exact position and from there, follow up without having to break again except on final check and firing bearing. As for pings, its better to ping on firing bearing since some merchant ships can hear your ping and it certainly diminishes your element of surprise - the chief ace up the sleeve of a submarine.

PS: How do you read and interpret A-Scope radar ?

A-scope is the green heartbeat radar, not the PIP radar (closer to sonar stack in the conning tower). You rotate the radar mast at radar depth or surfaced until a peak pops up indicating a possible surface contact. From there you see the range and for bearing, move to the PPI. PPI can give both exact and arbitrary bearings, so also work with your scope whenever possible. And dont leave it hanging for them seagulls to hand you to tincans...

Regards,
CS2k9

[Armistead]

Solo gave good advice, never trust sonar lines when you're under. The sonar line will give you an accurate direction, but not range. Many things take effect, if you go under the thermal, lines may even vanish, your speed will have effect. Your sonar lines may show different ranges, it may appear that escorts are much further away, but come up and take a peek in the scope the escorts could be right on you. So why they give you a true bearing, range not so much. Certainly you can get more accurate readings going slow above the thermal.

Sometimes I'll work plot and get course from far away using my scope, then dive, basically everything is worked out first, then I'll use sonar to get bearings and shoot.

Sonar only attacks are hard, you still need to get a good plot to put yourself in a position first, unless the group just happens to be coming over you.

[Doenitz2008]

[Hylander_1314]

Can anyone say SPAM!

[WernherVonTrapp]