I was dingin thistlegorm yesterday, did 2 dives on air. The first was just a 35 minutes go around the ship with no penetration, just discovering the place as it was my first time there. The other one was almost all inside going from one deck to the other. It was for 47 minutes with 20 minutes in the depth between 20-25 m inside the lower part. then about 16 minutes in depth between 15-18m checking the upper part then ascending and having the safety stop. This was on air using a 15L tank, we went up because of the NDL together with air consumption, I was out of the water with 60 bars left. Mild current and good visibility, I was lucky