Can I change my uboat number in the logbook after start of campaign
 

Using all the latest TWOS I modified captains name and uboat number in the journal logbook and it told me it was changing the name and number in the game config files. However in the game all radio messages go to a different uboat number. My journal says U-48 but all messages are to U-29. Can I fix this after starting the game?

You can only match U-boat number from ships journal to the one visible in your captains log, using OFEV ...