In the meantime I watched the pressure gauge, which told how the water was piling up above me, and the sensors which would let me know if anyone else was using sonar gear in the neighborhood. I wasn’t sure whether I wanted them to react or not. If they did, it would be progress; I’d know someone was down here who shouldn’t be — but it might be the same sort of progress the other three had made. It might not be grounds for too much worry, since fifteen or twenty feet of smashed hull would show on any sonar scope for just what it was, and supposedly the tank inside would not. Of course, some sonarmen are harder to fool than others.

I could look out, of course. The tank had ports, and a couple of them faced the opening where Pugnose’s stern used to be. I could even see things at times. There were flecks of phosphorescence drifting upward and streaks of luminosity not quite bright enough to identify in color which sometimes whipped past and vanished in the gloom and sometimes drifted for minutes in front of a port as though they marked the position of something which was trying curiously to look in. I was tempted — not very strongly, but tempted — to turn on my lights once or twice to see what the things were.

The wreckage was tumbling slowly. I had been assured that this wouldn’t happen — that weight had been distributed so that the sharp prow would always point down and leave the tank on top when I hit bottom — but there was no one to complain to. There also seemed to be nothing to do about it, and I began to wonder just what I could accomplish if the tank wound up in bottom ooze, or even on hard rock, with the wreckage on top of it. The thing had little enough maneuverability as it was. With very much extra weight, dropping ballast might not be enough to start me back toward the surface.

I couldn’t shift my own weight enough to affect the tumbling at all. The tank’s inside diameter was only about six feet, and much of that volume was taken up by fixed apparatus.