ok.. maybe one of those "ah ha moments" ?? Doubtful though.
After getting the distance and speed down all I needed to figure out was the bearing of the ship? I'm sure what I did was wrong, but I set my sonar guy to follow the closest ship, he kept reading out his bearing and all I did was turn the dial to what the sonar guy said the ships bearing was.
Direct hit from a distance of 1100 yards.
I dunno, I feel it was done by the seat of my pants and I got lucky.. I've gone through this over the years, GWX, SH4 and SH5.. I always give up at this point, lol I'm going to stick with it now.
EDIT!!
ok I now was able to sick two merchants..
I have map contacts on, so that is a huge help, I can easily get the distance and speed.. The distance I can get by a number of ways, I use the ruler

I use the sonar to ping and then the stadimeter.
as for the speed the only way I do it as of now is timing 3 minutes and marking..
Using the OTC realistic scopes mod there is something I can do to judge the speed using the TDC, but everytime I click it my guys say I have to wait 5 seconds or something.
I'd like to figure that out as well, but for now my biggest problem is the angle BS, lol
I keep adjusting until the attack map looks almost right, its obviously cheating as I want to go full realistic eventually and this method is not teaching me anything!