Once or twice they heard the sound of oars, as some Genoese galley passed up or down, but none came near enough to perceive them, and they crossed the main channel, and entered one of the numerous passages practicable only for boats of very light draught, without being once hailed.

A broad shallow tract of water was now crossed, passable only by craft drawing but a few inches of water; then again they were in a deeper channel, and the lights of Chioggia rose but a short distance ahead.
They paused and listened, now, for they were nearing the ship channel, and here the enemy would, if anywhere, be on the alert.

Coming across the water they could hear the sound of voices, and the dull noise made by the movement of men in a boat.
"Those are the galleys watching the boom, I expect," Francis said.
"Now, Philippo, we can move on.

I suppose there is plenty of water, across the flats, for us to get into the channel without going near the boom." "Plenty for us, signor; but if the boom goes right across the channel, heavy rowboats would not be able to pass.

There are few shallower places in the lagoons than just about here.