Hi Platon.

The reason for the alternating, was in both cases, a sudden illness of Lt. Sars.
You my probably be right about the date, I have it from Abelsen: RoNN ships 1940-1945. According to Valvatne`s own book "Norwegian Submarines at war", Ula left on 28 of October 1943 at 11 AM. He was asked to take command a couple of days before.
To bee sure about the exact dates, I will take a look in the logbooks at the Naval Museum in Horten next week, if they still exist then.

Regards Rolf