How do you change subs in campaign mode

[Brightwell]

In the office back in port I click on the submarines area and see the VII sub I want to upgrade to and have the renown to cover the quoted 2500 cost but despite trying to click on everything I can find when I go back from that screen I still have the type II. Am in the first flotilla around the end of 1939, is there a time restriction before I can get this sub?

If the answer is already in these pages, apologies but I went through 9 pages of this forum looking for it

[Brightwell]

In the office back in port I click on the submarines area and see the VII sub I want to upgrade to and have the renown to cover the quoted 2500 cost but despite trying to click on everything I can find when I go back from that screen I still have the type II. Am in the first flotilla around the end of 1939, is there a time restriction before I can get this sub?

If the answer is already in these pages, apologies but I went through 9 pages of this forum looking for it

[MissouriMedic]

You've done everything correctly. That should've worked.

I can't answer as to whether or not this is date-related, but that's a good theory. It sounds like a bug (allowing you to see the upgraded model as if it were available, but not actually being able to 'purchase' it)
I had some buggy issues when it came time to purchase the type III torpedos... so I do know that some minor bugs exist in the upgrading system... sounds like you found one of them.

[Lovo_Kasistan]

You have to double-click on the name of the boat you want in the list.