If you wish to use La Rochelle due to the use in the film Das Boot... be aware of a couple of things.
first, the real U-96 on which the novel and film are based upon, sailed from St. Nazaire not la rochelle.
Second, La rochelle was only used and referenced in the film because that port had changed very little since the conclusion of the second world war and would appear more authentic on film ( the das boot novel correctly uses St. Nazaire )
third, la rochelle was the base of operations for the 3rd flotilla which was briefly non existent in late 1939 and through 1940 and as such i dont believe it is even included as an option in SH3
La pallice was actually used as a u-boat base for the 3rd flotilla - the base was only briefly switched to la rochelle fairly late in the war before being redeployed to bases in Norway.
i am 95% sure it is not possible in SH3 or GWX to use la rochelle as a base of operations
__________________
|