If you use the Terrible T campaign you will/might run into a 'time warp'. To have a Tambor for the entire career DO NOT use the Small Patch and start a normal career with a Tambor, you will have it for the entire war. You can also start with any class boat and be upgraded to a Tambor for the remainder of the war.
I believe with the Terrible T campaign, somewhere in late 43 or early 44, depending when you get back to your home port, you will be warped back to mid 1942.
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