Vertically-variable ocean sail system

A method for operating a mechanical sail system, comprising:

• raising a lift carriage, a lower sail cylinder, and an upper sail cylinder to a top position within a silo;
• activating a first locking device to secure the upper sail cylinder at the top position;
• retracting the lift carriage and the lower sail cylinder to a bottom position within the silo;
• activating a second locking device to secure a top portion of the lower sail cylinder to a bottom portion of the upper sail cylinder;
• deactivating the first locking device;
• raising the lift carriage, the lower sail cylinder, and the upper sail cylinder to the top position within the silo;
• and
• activating the first locking device to secure the lower sail cylinder and the upper sail cylinder at the top position.

A mechanical sail, comprising:

• an upper sail cylinder, having a top plate and a base, the base holding a plurality of shot pins;
• a lower sail cylinder, having a diameter slightly less than a diameter of the upper sail cylinder, and having a top portion mating with the base of the upper sail cylinder, the upper sail cylinder and the lower sail cylinder removably connected by the shot pins;
• and
• a lift carriage, having a central spindle, the lift carriage mating with a base of the lower sail cylinder such that the upper sail cylinder and the lower sail cylinder are together rotatable around the central spindle, the lift carriage held within a silo mounted beneath a deck of a ship.