Diving Apparatus and a Scheme for Sinking Enemy Ships
A diving dress, a submerged boring engine, and notes on burning a fleet
One of Leonardo's schemes for underwater naval sabotage. The notes describe stopping and burning enemy galleys - slipping a small boat beneath the stern and firing them all at one stroke - alongside a full diving outfit: jerkin and hose, a breathing bag held off the chest by iron half-hoops, an inflatable ballast bag with a valve, sacks of sand, cork floats and a glass-eyed mask. Large drawings on the right show a screw-driven boring device mounted on a double hull to work entirely under water, with a diver beside it, while the text sets terms for a ransom pact with one Maneto. The page opens with the maxim 'Do not teach, and you alone will be excellent.'
On this page
Firing the enemy fleet at one stroke
Once the watch is set, slip a small boat beneath the stern and set every ship afire at a single moment; stop the masters' galleys, drown the rest and burn the fort of the bombard. The opening jottings sketch a plan of naval sabotage before any drawing is explained.
The diving dress: breathing bag, ballast and glass-eyed mask
A jerkin and hose, a little bladder for urinating, and a breathing bag held off the chest by iron half-hoops. A whole bag with a ball-valve lets the diver sink when deflated - pulled down by sacks of sand - and rise when inflated; a glass-eyed mask, a good knife against nets, and spare inflatable bags complete the outfit.
A boring engine worked entirely under water
On the right a device is mounted on a double hull with a thick screw turning within its nut (the 'female'); a note insists that everything - the whole locking mechanism - stays under water, with the man stationed beside it. It is designed to bore into an enemy ship's hull unseen.
'Do not teach, and you alone will be excellent'; the pact with Maneto
The sheet opens with a personal maxim and closes on the terms of the enterprise: make a pact by legal instrument that half the ransom be yours, keep the prisoners' deposit near Maneto and let payment pass through his hand, and carry a horn to signal whether the deed has succeeded.
