Harbour works, dredges and pumps
A silt-proof harbour mouth, bucket dredges, footed twin pumps and a counterweighted lever
A sheet of hydraulic and excavation engineering. Leonardo shows a harbour mouth flanked by wing-walls to keep out wind-blown sand, twin pumps footed to avoid the mud, and several dredges, one on floating hulls, another measured at 3 braccia per arm, and a wheel of rotating shovels. A note in the upper margin analyses a counterweighted lever with a driving cord, reckoning its mechanical advantage. The devices share the theme of moving water and spoil.
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A harbour mouth that resists silting
Leonardo designs a harbour mouth flanked by two wings of wall so that the wind cannot drive into it the sand that the shore sheds. The walls shelter the opening from wind-blown sediment. It is a study in keeping a port navigable.
Twin pumps raised on feet
A pair of pumps stands on pedestals in the water, their tubes footed clear of the bottom so that mud does not block the intake. Leonardo notes that such a pump would not draw the water right down to its floor. The feet trade complete emptying for clean intake.
Bucket dredge mounted on hulls
A chain-and-bucket dredge is carried on floating hulls to excavate a river or canal bed. Leonardo remarks that this design does not spill the spoil from the upper part of the rising buckets. It is one of several dredging schemes on the sheet.
A second dredge (3 braccia per arm)
Another dredge is sketched, dimensioned at 3 braccia per arm. It joins the family of excavating machines for clearing waterways. Only the measurement is given.
Rotating-shovel excavator
In the lower left corner is a device of rotating shovels. Leonardo measures two and a half braccia from the centre of the axle to the cutting edge of each shovel. The wheel of blades would dig as it turns.
Counterweighted lever with driving cord
A bar lettered d, c, a, e, f, n, b works as a balance: a load of a hundred at one end is resisted by the arm c d e f, while n acts as an accidental weight. Leonardo reckons the mover n advancing two miles drives the load b through ten, and calls for the pivot to turn with the least possible friction. The note calculates the mechanical advantage of the linkage.