WoS parallel torpedo attack comp setup

[alien1234]

Hi I have had a lot of success of doing guess work on a standard torp attack of a 90 deg angle.
I.E :- im facing north 0 deg stationary, the enemy ship is running West270deg to East 90deg at estimated 5 to 10 kts and an aprox range of 1000metrs with the setup at 300deg on the periscope.
So my guess work for the computer set up is :- AoB stboard side 90deg angle, range 1000metrs, speed 7kts, torp setup its self is 1 mtr depth fastest speed and impact detination, after entering the data I wait until the ship nears 0 deg on the periscope, usually fire off at 350deg, I dont bother resetting the distance. 50% of the time I get a direct centre hit, 30% its either a bow or stern hit, 20% of the time a miss usually only by a few feet, either by my speed guess is out or the torp has been spotted. My realism is set to high so I get no map data etc, the only thing I can use is the torp tracking lines on the map and the periscope angle view markings on the map, how ever I dont use these on an easy set up, I do use it after firing the torp.

Now what I want to know is how do I set up for a parallel torp attack?
I.E I found a small convoy, I cant use the deck gun as 1 ship is armed (take this out first so I can use the deck gun). the convoy is running east 90deg at 6kts, im running east 90deg at 6kts at a range of 800mtrs and on the south side of the convoy, I know the periscope angle will be around 270deg, computer setup as 6kts range 800mtrs.
How do I work out the angle on the bow and setup for this type of attack? Also at this point I have to use the torp track angle on the map I know this is cheating but I cant work it out lol and I havent found anything on the internet for this type of attack. Thanks