On the far eastern horizon, where the water slipped round a corner of hill, there was a long trail of smoke.

The streamers thinned out, and seemed to come from some boat well round the corner, but I could see at least two boats in view.
Therefore there must be a long train of barges, with a tug in tow.
I looked to the west and saw another such procession coming into sight.
First went a big river steamer--it can't have been much less than 1,000 tons--and after came a string of barges.

I counted no less than six besides the tug.

They were heavily loaded and their draught must have been considerable, but there was plenty of depth in the flooded river.
A moment's reflection told me what I was looking at.

Once Sandy, in one of the discussions you have in hospital, had told us just how the Germans munitioned their Balkan campaign.