⚠This manuscript page contains mirror-writing <note>Leonardo famously wrote from right to left, a habit that may have been a personal preference or a way to prevent ink smudging as a left-handed writer.</note> by Leonardo da Vinci. The image exhibits significant ink bleed-through from the reverse side and surface staining typical of aged paper.

UNPUBLISHED LEAVES OF LEONARDO DA VINCI

(Royal Library of Windsor Castle)

CIVIL, MILITARY, AND NAVAL ARCHITECTURE

Édouard Rouveyre, Publisher, 76 rue de Seine, Paris

for making the ship concerning the motion of ships how it turns

Milan Leonardo often noted his location; this likely dates the observations to one of his periods of residency in Milan under the patronage of the Sforza family or the French governors.

The following text is translated from Leonardo's technical Italian notes regarding the diagrams of the hull and mechanical systems.

The structure of the vessel must be such that it resists the percussion of the waves original: "percussione dell'onde", and the curvature of the sides should be designed to divert the water with the least resistance.

Regarding the motion of ships, consider how the rudder acts as a lever against the density of the fluid. When the rudder is turned, the pressure of the water against its surface creates a force that rotates the stern, thereby directing the prow in the opposite direction.

The center of gravity must be maintained low to ensure stability against the wind.

In the mechanical studies:
The rotational mechanism referring to the pulley and gear sketches demonstrates how force is multiplied through the diameter of the wheels. By increasing the distance from the center, a smaller weight can move a much larger load, though it must travel a greater distance.

The wheel turns here

The profile sketch of a human bust in the margin is a classic example of Leonardo's "grotesques" or character studies, often drawn instinctively alongside his scientific observations.