Finally, we arranged for the collapse of the hull. I had taken for granted that we could use ordinary explosive squibs, forgetting how sound affected a person living in liquid. The things simply weren’t to be had; they were never used here.

We finally settled the problem — we thought — by opening all the interhull inspection plates and removing as many of the bolted braces — the ones which had to be removable for maintenance purposes — as possible. It seemed pretty certain that pumping out the hull now could hardly help but cause it to collapse.

A good deal of time was wasted trying to improvise something that would start the ballast pumps either by time or from outside. It finally occurred to someone — not me — that there was nothing to prevent us from starting them from inside and then leaving, shutting the lock after us. Pressure would not start to drop until the hull was sealed off from the ocean.

That seemed to finish the job. The sub was already weighted in near-equilibrium with outside ballast, so we picked it up and began to swim toward the nearest entrance. There were ten of us altogether, and the load wasn’t too bad. We brought it to a halt under the roof opening, pushed it up until it met the interface and left it there while we donned outdoor coveralls.

I wasn’t yet accustomed to these. I hadn’t yet gotten around to asking what the little tank on the back was for — my theory didn’t account for it, as you may remember. There was no chance to ask now. Bert helped me to adjust everything properly, though I wasn’t sure what he was doing part of the time. In three or four minutes we were casting off the outside ballast, and the sub was entering water for the last time.

We left a little negative buoyancy on her, and some of us walked supporting the hull while the rest swam and pushed it. Bert and I hadn’t made any special plans about where the wreck should be staged; obviously it shouldn’t be too close to an entrance, or there’d be little excuse for not having found it sooner. On the other hand, it wouldn’t be possible to carry the thing too far away. We gave it an hour of travel and then let the hulk settle to the bottom.

Personally, I couldn’t have found my way back to the entrance we had used, and it would have been sheer luck if I ran into one. Bert and the others didn’t seem worried, however. I assumed that they either knew the ground or had some navigation scheme I hadn’t yet learned about. The only light came from our own lamps, whose radiance formed a tiny glowing dome in the immense blackness of the Pacific. We were far out of sight of the tent area, as I still called the farm region in my own mind. I didn’t even know the direction in which that lay, and knowing would have done no good since I had no compass.

Bert gestured me toward the sub’s lock. I opened it and went in. In a way, I hated to do this, but the idea still seemed good.

What I had to do inside was done quickly; it amounted only to closing two switches. I closed the locks behind me and joined the others.

We had recharged the boat’s batteries, and there was no worry about there being energy enough to empty her. I was quite proud of remembering that point — large as the tanks were, adding the hull volume to them meant a tremendous additional job for the pumps. However, I had barely reached the rest of the group when we were reminded of something neither Bert nor I had thought of, and for which there was not the slightest excuse for either of us.

Emptying the ballast tanks with the flotation tanks still full put positive lift on the boat. Naturally, she started up.

Fortunately the initial rise wasn’t too quick. I was able to catch her, open the lock under power — I couldn’t have done it manually with pressure difference already set up — and unseal and open the lift-jettison valves. By the time I got outside again the ship was a couple of hundred feet from the bottom. The swimmers were flocked around covering the scene with their lights: I looked at the top of the hull and saw the oily stream of lift fluid pouring out. The rate of climb was already slowing, and in a minute or two it ceased and reversed. We followed the ship back to a place on the bottom not too far from the one we had picked. And there we waited. And waited. And waited. The helpers talked finger-language among themselves. Bert and I couldn’t talk at all, since the pad had been left back at the entrance when we had donned the coveralls. We each knew just about what the other was thinking, though, and as time went by and the hull just lay there we began to exchange inquiring glances.

The pumps had had time to handle the total volume by now, certainly. The inside of that ship should be practically a vacuum.

We had paid no attention to what was left in her air tanks. There couldn’t have been enough to matter at this pressure. No bubbles had appeared from the ballast vents, but any air released by the tanks inside might well have gone into solution at this pressure before being ejected.

The problem was not whether the inside pressure was zero or some small number of atmospheres, though; it was what we could possibly do about the hull’s failure to collapse. The pressure would stay down until long after the pumps ran out of fuel, and even that would be a long time since they must now be running free. Considering the general reliability of Board equipment, it could be months before some tiny leak let the internal pressure build up again to the point where even power could open the locks. I didn’t know how long we could sit around without more oxygen-food, but it certainly wasn’t months. As a matter of fact, it was going to be fairly hard to explain the three days or so which had already passed since I had seen Marie. Any more would be much harder, but I couldn’t afford to see her again without a convincing story about Joey all ready.

A depth charge would have been helpful. Even a squib would probably have been enough; the hull, after what we had done to it, must be very, very close to its limit. Unfortunately, there were still no explosives available.

All I could think of was to take the sub back, have Bert or me go into the conversion room, attach the sub to the lock which was supposed to connect the room with just such visitors, go through whatever had to be done to get the man back to surface pressure and pump the room back down so he could get into the sub to start everything over. I didn’t like the idea. I was pretty sure Bert wouldn’t either, but I couldn’t find out under the circumstances. It wasn’t the sort of idea which could be transmitted by any gestures I knew. It was going to take quite long enough with the writing pad.

I did manage to make Bert understand that we would have to go back for the pad and a conference. When I tried to indicate that the sub should be brought with us, though, he vetoed the suggestion flatly. After a minute or two I stopped trying to push the idea. As I said, I wasn’t too fond of the basic plan anyway.

He made some gestures to the others, and all but four came with us; the four settled down on a level patch of mud twenty yards from the ship and started a game of some sort. At any other time I’d have been curious about the details.

The swim back was, of course, much quicker than the one out — or rather, would have been if we had made it.

I don’t know how far we got in the eight or ten minutes we were swimming. I suppose a quarter of a mile is a reasonable guess. I’m not the world’s most efficient swimmer, and even I wasn’t overworking.

The interruption, like so much else which had gone wrong with our plans, should have been foreseen, but none of us had foreseen it. If we had, we wouldn’t have been waiting anywhere around the sub after her ballast pumps had started.

It was obvious enough in nature, and the only reason I didn’t realize what had happened in the first second after the event was, of course, that I wasn’t really conscious.