I hadn’t expected to see it hit bottom, of course. I would certainly never have expected to see what happened when it did.

For the most part, level stretches of sea bottom tend to be on the gooey side. They may call it globigerina ooze or radiolarian ooze, but it’s usually ooze. You can meet with coral and sand and other firm stuff in shallow water and honest rock at times on slopes, but where it’s level you expect something like a cross between ordinary mud and the top couple of inches of a stagnant pond. When something hard and heavy lands on it, even gently, you don’t expect the bottom to give it much support. You may sometimes be surprised on this matter, but you never count on anything bouncing off the sea bottom.

Pugnose didn’t exactly bounce, I have to admit, but she certainly didn’t behave properly. She hit the lighted surface thirty or forty yards from the edge, and perhaps twice as far from me. I could see easily. She touched, as expected, and sank in as expected. There was no swirl of silt, though — no sign of the slow-motion splash you normally see when something lands in the ooze. Instead, the bow section disappeared almost completely into the smooth surface while a circular ripple grew around it and spread away from the point of impact. Then the wreckage eased gently back up until it was half uncovered, then back down again, still in slow motion. It oscillated that way three or four times before coming to rest, and each rebound sent another ripple spreading out from the spot for a dozen yards or so.

By the time that stopped, so had my tank. I felt it hit something hard — rock, for a bet, and I’d have won. Then it began to roll very, very gently toward the light. I couldn’t see the surface I was on at all clearly, but it seemed evident that it was a solid slope which would deliver me beside the Pugnose in two or three minutes if I didn’t do something about it. Fortunately, there was something I could do.