The Esse 850 is an 8.5 metre long racing sportboat designed by Umberto Felc

and built by Josef Schuchter Sportboats of Stafa, Switzerlan

The first hull was sold in 2004 and the Esse 850 International Class Association was begun in 2005 in Europe. The design has achieved some popularity in Europe with over 110 boats in the one-design fleet by mid-2009. The design is unusual in that it is a very high performance sportboat designed to be raced with a crew of 1-4 sailors. Class rules established by Esse 850 International Class have a maximum crew weight of 280 kilos which effectively limits the crew to 3 athletic adults. The design is characterized by a very large ballast to displacement ratio and a narrow hull of 2.2 metres Beam (nautical), beam and a tall mast with a high aspect ratio sail plan. In concert with most sportboats, the Esse 850 is designed as an alternative to the complexity of traditional sloop-rigged sailboats, with an emphasis on ease of handling with a small crew and exceptional speeds. Typically, sportboats such as the Esse 850 are much lighter and more powerful than their traditional counterparts. The reduced weight is usually the result of smaller accommodation volume in the hull and lower

freeboard In sailing and boating, a vessel's freeboard is the distance from the waterline to the upper deck level, measured at the lowest point of sheer where water can enter the boat or ship. In commercial vessels, the latter criterion measured relativ ...

, hence less hull structure. The weight reduction over traditional designs means that a larger percentage of the total weight of the boat is concentrated in the keel providing greater stability and the ability to carry a larger sail plan for greater power. The weight of the entire boat is 1180 kilograms, including the

hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

and

standing rigging Standing rigging comprises the fixed lines, wires, or rods, which support each mast or bowsprit on a sailing vessel and reinforce those spars against wind loads transferred from the sails. This term is used in contrast to running rigging, whic ...

. The design concentrates the righting moment of the keel in a 770 kilogram torpedo-shaped bulb at the end of an airfoil shaped fin. The ballast to displacement ratio is 0.61 which provides an exceptionally "stiff" platform. The high righting moment allows the design to carry a larger than normal sail area which increases power and consequently speed through the water. The Esse 850 is an example of the latest design concepts in high speed hulls and sail plans. The sail plan is characterized by a large

mainsail A mainsail is a sail rigged on the main mast of a sailing vessel. * On a square rigged vessel, it is the lowest and largest sail on the main mast. * On a fore-and-aft rigged vessel, it is the sail rigged aft of the main mast. The sail's foot i ...

and a high aspect ratio jib in a

fractional rig A fractional rig on a sailing vessel consists of a foresail, such as a jib or genoa sail, that does not reach all the way to the top of the mast. The forestay is a wire that secures the mast to the front of the boat. With a fractional rig, th ...

design. These high speed fractional rigs are a nearly ubiquitous feature on sportboats and are used for their ease of handling and their high lift and low drag characteristics. Hull shapes on sportboats are typically designed so that the hulls plane at high speeds. These hull designs are characterized by fairly sharp bows to allow them to penetrate waves with reduced drag and a flatter underbody

aft "Aft", in nautical terminology, is an adjective or adverb meaning towards the stern (rear) of the ship, aircraft or spacecraft, when the frame of reference is within the ship, headed at the fore. For example, "Able Seaman Smith; lie aft!" or "Wh ...

of the bow. The flat underbody develops lift as speeds increase and the hull rises higher in the water, which reduces the

wetted area The surface area that interacts with the working fluid or gas. In maritime industry, maritime use, the wetted area is the area of the hull (watercraft) which is immersed in water. This has a direct relationship on the overall hydrodynamic drag of ...

and decreases drag, allowing higher speeds to be achieved. The traditional

spinnaker A spinnaker is a sail designed specifically for sailing off the wind on courses between a reach (wind at 90° to the course) to downwind (course in the same direction as the wind). Spinnakers are constructed of lightweight fabric, usually ny ...

is replaced with a

gennaker A gennaker is a sail that was developed around 1990. Used when sailing downwind, it is a cross between a genoa and a spinnaker. It is not symmetric like a true spinnaker but is asymmetric like a genoa, but the gennaker is not attached to the ...

that is set on an extensible

bowsprit The bowsprit of a sailing vessel is a spar extending forward from the vessel's prow. The bowsprit is typically held down by a bobstay A bobstay is a part of the rigging of a sailing boat or ship. Its purpose is to counteract the upward tensio ...

. Using a bowsprit allows the size of the

to be a much larger

sail A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails ma ...

than would be possible with a

. The speeds achieved downwind by these designs can be remarkable. In the case of the Esse 850, speeds of 17

knots A knot is a fastening in rope or interwoven lines. Knot may also refer to: Places * Knot, Nancowry, a village in India Archaeology * Knot of Isis (tyet), symbol of welfare/life. * Minoan snake goddess figurines#Sacral knot Arts, entertainme ...

(19.5 mph/31.4 km/h) are readily achievable in true wind velocities greater than 25

. The Esse 850 design was selected as the

European Yacht of the Year European, or Europeans, or Europeneans, may refer to: In general * ''European'', an adjective referring to something of, from, or related to Europe ** Ethnic groups in Europe ** Demographics of Europe ** European cuisine, the cuisines of Europe ...

in 2005 and the Sailing World Magazine Overall Boat of The Year in 2007. There is an active owners grou

that promotes the design. Distribution in North America is by Esse Pacific Northwes

External links

Felci Yacht Design

Schuchter Sportboats

Esse 850 International Class Association

Esse Pacific Northwest

Esse 850 Italy
{{Trailer sailers and Trailer yachts worldwide Keelboats 2000s sailboat type designs