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Old 05-06-07, 09:49 AM   #13
ronbrewer
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Join Date: Jul 2005
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Quote:
Originally Posted by Laffertytig
im havin real probs hitin targets usin manual settings as all my shots are all goin aft.

im doin the naval academy torpedo mission and goin for the ship due NE which is movin S at 7 knots so ive got the speed sussed. heres what im doin

set tdc to manual, lock periscope to target and set course to 90

once on course i use the protractor method to get AOB which i imput using notepad, i also set target speed

set all torps to fast set tdc to auto open doors and fire.

so what am i doin wrong?
I'm not sure of your issue but it may be related to having the target locked on the periscope while in auto TDC and entering items from the notebook. I haven't used the notebook since 2005 but I think it is used while the TDC is in auto mode (I could be wrong).

However, since you have the target's true course it comes down to how you position your sub. Also, when I input data on manual TDC in the conning tower I keep the periscope at zero bearing to cut down on confusion. I always look at my solutions from the aspect of what it would be if the target were directly in front of me. After that when you set the TDC back to auto it will update the settings when you point the scope back onto the target.

Here's an approach to the situation you mentioned:

Since the target's course is 180 and your sub is on course 90, if the target's bearing to you is NE (45 degrees) then that is an AOB of 135 starboard (90 + 45). Since you are on a perpendicular course to the target you just take the amount of degrees the periscope has turned from zero bearing and add it to the target's AOB 90. Below are examples of AOB numbers when on perpendicular course (to help clarify what is going on):

Target bearing = 350
AOB = 80 (you add a negative 10 in this case)

Target bearing = 0
AOB = 90

Target bearing = 10
AOB = 100

Target bearing = 20
AOB = 110

Target bearing = 30
AOB = 120

Target bearing = 40
AOB = 130

Target bearing = 45
AOB = 135

In a situation like the one you are in where the target is already well past your zero bearing you can turn the sub towards it to cut down on the torpedo's gyro angle. For example, if you changed your sub's course from 90 to 110 you then have the following:

Target bearing = 350
AOB = 100

Target bearing = 0
AOB = 110

Target bearing = 10
AOB = 120

Target bearing = 20
AOB = 130

Target bearing = 25
AOB = 135

That would cut 20 degrees out of how much the torpedo would have to turn when it leaves the sub (improving the accuracy of its run).

Basically, once you know the target's true course there are games you can play with the positioning of the sub since the math involved with the AOB is straightforward.

Hope this helps,
Ron

Last edited by ronbrewer; 05-06-07 at 12:19 PM.
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