Ladder pattern Torpidoes becomes usefull during a Convoy attack
when you have been spotted by the Escort .
Do not fire them before to have been spotted , as a TI/II/III can do the job easily and without fuss and fancy setting .
Few things to remember :
#1: Check the Ship in the convoy who has the highest draft ~usually a big Tanker or a C3~ . In this case around 10m under waterline .
#2: Set the FAT Torp to magnetic pistol , depth 10.5m .
#3: if the Convoy is 2000m away (exemple) , aim for the first or second leading ship in the Convoy and set the straight line to 2500m .
#4: Set the pattern to run ahead of the Convoy and not behind because as the Convoy keep moving , your Torp will loose time during its pattern and can end up behind the Convoy .
#5: Choose a short pattern ~800m~ as most ship in a Convoy are about 400-500m away from each other .
Because you do not know which Ship your Torp will hit , it is better to choose a magnetic pistol , as an impact one will need a good angle to detonate and not to go "dull" on the ship 's hull .
You cannot guess at which angle the Torpido will hit ...
Choosing a mag pistol set at 10.5m will allow the torpido to go easily under ANY ship with a very strong chance to detonate .
Good luck
Cheers .