at 1st sorry for my orrible english!
at 2nd if you wont take the carrier or the BB and can't find it lisen me, i do the same way at the end of tolerance, if you see in the map the red way (supply route) you hear she start at Gibilterra and end at Malta, put your boat at the start way in Gibilterra and armed you whit many many patience because before or after she (carrier or BB) transit in front of you.....
I hope you know what a mean and please sorry me for my disgusting english
T_T
Good Luck!