Project Green Jet - a vision of the future of sailing

“That was the reason we decided to create a really new yacht design concept! To push the boundaries. Everything started with my master’s degree in which I was trying to search for the new future guidelines of yacht design and construction, especially in sail boats and try to find the vision of nautical trends and movement.”

The SY120 and why it is special

The object of Sifrer’s degree became a 36 m futurist carbon super yacht, which he named the SY 120, a completely new design concept and solutions for basic sailboat elements. The research for the project took him four years and the degree project earned him both educational and industry acclaim in yacht magazines world wide.

What set the SY120 apart from everything before it, was its wholistic approach to sailing and the use of automated adjustments.

From Wikipedia’s excellent resource on the physics of sailing: “The energy that drives a sailboat is harnessed by manipulating the relative movement of wind and water speed: if there is no difference in movement, such as on a calm day or when the wind and water current are moving in the same direction, there is no energy to be extracted and the sailboat will not be able to do anything but drift. Where there is a difference in motion, then there is energy to be extracted at the interface, and the sailboat does this by placing the sail(s) in the air and the hull(s) in the water.

Sails are airfoils that work by using an airflow set up by the wind and the motion of the boat. The combination of the two is the apparent wind, which is the relative velocity of the wind relative to the boat's motion. The sails generate lift using the air that flows around them. The air flowing at the sail surface is not the true wind.[3]

The sail alone is not sufficient to drive the boat in any desired direction, as a sail by itself would only push a boat in the same direction as the wind. Sailboats overcome this by having another physical object below the water line. These include, a keel, centerboard, or some other form of underwater foil or even the hull itself (as in catamarans without centreboard or in a traditional proa). Thus, the physical portion of the boat which is below water can be regarded as functioning as a "second sail". Having two surfaces against the wind and water enables the sailor to travel in almost any direction and to generate an additional source of lift from the water.

The under-water area of SY 120 is composed of two keels with inner volume and high density ballast. The keels are attached at angle of 30 degrees to the sides of the transversal hull structure. One keel has two blades with two pipes inside, attached with inner volume at the bottom and connected with a pump to the other side. The pump pushes ballast from one volume to another through one of the pipes, according to the angle of lean. Computers control the amount of ballast in the volumes.

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