Canal dam with a sluice gate raised by a windlass
A long embankment and water-gate; the winch a gathers the chains that hold the cateratta
A bird's-eye view of a long embanked canal or river guarded by towered water-gates, drawn diagonally across the sheet. Below, in detail, a windlass marked a is wound until its shaft gathers up all the chains that hold the sluice gate (cateratta); once the chains are collected and the gate meets the shaft it is thrown onto a lever, as shown in the second device below. Further faint notes appear on the sheet that are not part of the transcription, and the scholarly tags associate the leaf with studies of moving water, waves and foam.
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Windlass a lifting the sluice gate
The windlass labelled a is turned until its shaft (stile) winds up all the chains that support the sluice gate. When the chains are fully gathered and the gate reaches the shaft, the gate is thrown onto a lever. The same lever action is shown in the second device drawn below.
Canal with towered water-gates
A long embankment carries the channel diagonally across the sheet, punctuated by fortified gate-towers that regulate the flow. The sluice detailed below would be raised and lowered to control the water passing the barrier.
Embankment and gate structure
The heavy banked works and the masonry gate-piers are drawn to show how the barrier crosses the waterway. Small figures give the scale of the embankment and its openings.