Fabulous answer gents
you have been a great help.
I can get back to my scenario when I get back from work today, thankfully its in peacetime, but I have to avoid contact with French Naval units if possible, so im trying to loop around the submarine whilst keeping a close eye on his movements.
Yes the change in bearing rate is what I meant by the speed difference, I got confused into thinking this affected the TMA solution in the TMA plotter
thanks for clearing me up on that.
I'm still learning as you can tell :P
Cheers