Sailing boats, wind force, and fortress-cost notes
Rigged boats with named sail parts and wind directions, over cost notes for the fortress of Monte a Santa Maria
The recto carries three sketches of rigged sailing boats, labelled with the parts of a lateen sail (antennale, gratile, ballumina, penna, carro) and with the stern, prow and rudder. Adjacent notes describe how a vessel sails toward the scirocco under a greco wind and mark where the driving force of the wind is felt, at points f and g. The lower half turns to fortification accounting: the ditch, walls and enclosure of the fortress of Monte a Santa Maria are costed at 5942 ducats, and the ditch with the tower and its barbicans at 2393 ducats. A small subtraction (5942 minus 2393, giving 3549) stands beside the boats.
On this page
Wind direction and where a sail feels the wind's force
Two of the boats are annotated with the behaviour of the wind. One 'travels toward the scirocco with the wind that comes from the greco, and the power of the wind is at f'; the other 'comes from the scirocco with the greco wind, and the power of the wind is at g.' The notes tie the driving force on the lateen sail to the compass directions.
Nomenclature of the lateen sail and hull
The rigging is labelled on the figures: d c the yard-line (antennale), a b c the bolt-rope (gratile), a d e the leech (ballumina), d the peak (penna) and c the car (carro), with a note that 'the yard sits here on the mast, toward the east.' A lower hull sketch names the stern (poppa), prow (prua) and rudder (temone).
Cost of the fortress of Monte a Santa Maria
The lower half prices the defenses. The ditch with the walls and enclosure of the fortress of Monte a Santa Maria comes to 5942 ducats. The ditch and its walls, the defense of the stronghold, and the tower with its barbicans, 25 braccia thick and 20 high and all solid save for the defensive openings, come to 2393 ducats.
Subtraction reconciling the two estimates
Beside the boats a short sum sets 5942 over 2393 and draws the difference 3549, reconciling the two fortress figures given in the prose below.