Ohh Mann, you lost your fin

We were on the edge of Kornati National Park in Croatia, and the skipper had made his feelings about the current absolutely clear during the briefing. It was too strong. We were going in anyway.

I pulled Mann aside before we hit the water.

— "On three, we jump together and go straight down. No air in the BC, negative descent, immediately."

He gave me the OK signal. I counted us in.

— "One, two, three ... go."

Negative descents were familiar territory for me by then, so my only real concern was keeping up with my ear compensation on the way down. I reached the plateau, grabbed a rock to hold myself against the current, and looked up for Mann. He was still on the surface, drifting. I gave the "down, down, down" signal repeatedly. He kept drifting. There was nothing else for it, I surfaced and went to join him.

The boat joined us and repositioned us somewhere with a more forgiving current, we checked our air and kit, and went again. This time the descent went without a hitch. We hit the plateau, exchanged OK signals, I checked his air and decided we had enough for a reasonable dive. We followed the slope down.

At eighteen metres I found an isolated rock and started circling it slowly, looking for marine life, Mann following a metre or two behind. After one full circuit I turned to check on him, and noticed he was missing a fin.

My first instinct was to tell him immediately, but I caught myself. No point alarming him in the middle of a dive. I signalled him to hold position while I did a circular search. Nothing. The fin had simply vanished into the current. I signalled Mann to retrace our route and started searching along the reciprocal bearing, hoping to find it somewhere behind us. Mann followed along quite happily, swimming with complete normality, entirely unaware that he was doing so with one bare foot.

I should mention at this point that Mann is a tall man. Notably tall. His feet are, proportionally, enormous, which is the only explanation I have for why he could kick his way through a dive without noticing that half his propulsion system had disappeared.

We arrived back at the plateau. I asked him to hold position again and did another sweep. Still nothing. At that point there was genuinely nothing left to do, so I showed the abort signal. We checked our air and began ascending.

We surfaced right beside the boat. I told Mann to grab the rope, waited until he had a firm hold, and then said it:

— "Mann, you've lost your fin."

He looked at me for a moment.

— "No. You're kidding."

He was not kidding. Neither was I.