A nice intercept!
It's always nice if a plan comes together
with or without the mobo (don't use it myself).
I have one comment though. A lone ship is always reported with speeds like slow or medium, unless BdU gives another contact report (like in your case).
This is the weak point of any calculation. You took 6 but the range could have been 4-7 or even greater.
What I do is calculate the position with a range of 7.5 when reported slow and then just wait for it. It's a bit dissapointing if it's much slower, but better than missing it altogether.
With convoys, you can always read the exact speed from the contact report...
There are a couple of other considerations as well. The contact report seems to be from 14:50. It is now 14:53. That's hardly any difference, but nexttime it may differ half an hour. It's just a matter of how quick you can get out of time compression.
You also don't want to cross the target's path literally, because it can spot you an start zig-zagging. you want to lay and wait submerged. The range of view depends of the time of day, the wind speed and fog. I would say it's max 7000 meter
I have made the convoy intercept 'theory' below which is based on some other basics that you can find on this forum, but has these things included in the calculation.
