sorry, Tweety, my answer before was very brief.
now I got some more time to ask, why do you like to shoot at this aob?
what I can see from above posted image, you are in a perfect position to infiltrate the convoy (surfaced or submerged depending on wheather or sight, or radar-equipment on DDs).
just let the lead escort sail by and run silent at a perpendicular course, you should then find yourself between first and second column and range would be no problem any more. your shots on targets within a range of 1000m will always hit (almost
). you could fire even your stern-torpedo and take out a second ship in one run.
just my ideas .......