New Patrol Zones

[Stiebler]

Is it possible to create new patrol areas that are not part of the existing grid?

I regret that the short answer is No.

The grid pattern itself seems to be hard-coded.
The U-boat knows when it reaches a grid because:
a) it checks its current latitude and longitude.
b) it tests whether this can be converted into a grid.
c) If so, it compares the grid with the assigned grid. If the two grids match, you have reached the assigned patrol grid.
All the above is definitely hard-coded.

If you are making a Pacific campaign, you will need also to make one of the Far East bases your Home Base. Otherwise, you will never be able to update your U-boat with new equipment, nor to change your torpedo load-out.
I think GWX has the ability to allow you to assign a Far Eastern flotilla (12th Flotilla) to Penang.

Stiebler.