In watercraft

Watercraft

A watercraft is a vessel or craft designed to move across or through water. The name is derived from the term "craft" which was used to describe all types of water going vessels...

, a racing shell (also referred to as just a fine boat (UK) or just shell) is an extremely narrow, and often disproportionately long, rowing boat  specifically designed for racing

Sport rowing

Rowing is a sport in which athletes race against each other on rivers, on lakes or on the ocean, depending upon the type of race and the discipline. The boats are propelled by the reaction forces on the oar blades as they are pushed against the water...

 or exercise. It is outfitted with long oars, outrigger

Outrigger

An outrigger is a part of a boat's rigging which is rigid and extends beyond the side or gunwale of a boat.In an outrigger canoe and in sailboats such as the proa, an outrigger is a thin, long, solid, hull used to stabilise an inherently unstable main hull. The outrigger is positioned rigidly and...

s to hold the oarlocks away from the boat, and sliding seats. The boat's long length and semicircular cross-section reduce drag to a minimum. This makes the boat both fast and unstable. It must be actively balanced by the rowers to avoid tipping. Being able to balance, or "set" the boat while putting maximum effort into the oars is therefore an essential skill of sport rowing.

History

The racing shell evolved from the simple working rowboat. Boats with longer hulls

Hull (watercraft)

A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...

 and narrower in beam

Beam (nautical)

The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...

 were developed in the early 19th century specifically for team racing. These dedicated boats were the first boats that could be called racing shells, and they have since evolved into the highly specialized forms used today.

Riggers

A narrower boat provides a sharper angle to the bow and a smaller cross-sectional area reducing drag

Drag (physics)

In fluid dynamics, drag refers to forces which act on a solid object in the direction of the relative fluid flow velocity...

 and wave drag

Wave making resistance

Wave making resistance is a form of drag that affects surface watercraft, such as boats and ships, and reflects the energy required to push the water out of the way of the hull. This energy goes into creating the wake.-Physics:...

, and avoiding hull speed

Hull speed

Hull speed, sometimes referred to as displacement speed, is the speed of a boat at which the bow and stern waves interfere constructively, creating relatively large waves, and thus a relatively large value of wave drag...

 limitations at race speed. The first racing shells, while narrower than working rowboats, were limited by the width necessary to mount the oarlocks on the boat's sides ("gunwale

Gunwale

The gunwale is a nautical term describing the top edge of the side of a boat.Wale is the same word as the skin injury, a wheal, which, too, forms a ridge. Originally the gunwale was the "Gun ridge" on a sailing warship. This represented the strengthening wale or structural band added to the design...

s"). By attaching riggers to the gunwales, the oarlocks could be placed farther out, two things happened: oars got much longer, providing more length to the strokes, and hulls got narrower, until they were as narrow as it was possible while still retain sufficient buoyancy and balance.

Materials

Originally made from lapstrake wood

Wood

Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...

, shells are now almost always made from a composite material

Composite material

Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...

 for strength and weight advantages. The first composite shells were made from a form of papier-mâché

Papier-mâché

Papier-mâché , alternatively, paper-mache, is a composite material consisting of paper pieces or pulp, sometimes reinforced with textiles, bound with an adhesive, such as glue, starch, or wallpaper paste....

 and became popular in the 1870s. Modern shells are usually made of carbon-fibre reinforced plastic in a honeycomb

Honeycomb

A honeycomb is a mass of hexagonal waxcells built by honey bees in their nests to contain their larvae and stores of honey and pollen.Beekeepers may remove the entire honeycomb to harvest honey...

 structure. They are manufactured by either cold laying up of the carbon, which is then left to set, or by using heat curing, which ensures that the carbon fibre composite is properly set. The best shells are characterized by their "stiffness", as the lack of flexing means none of the force exerted by the rower is wasted in twisting the boat.

Sliding seats

A rower on a fixed seat is limited in the amount of power he can apply to the oars by the strength in his upper body and the distance he can pull the oars on each stroke. After riggers were added to the shell allowing the use of longer oars, rowers took advantage by taking longer strokes and using their legs during the stroke. At first, the athletes wore trousers with wear resistant leather

Leather

Leather is a durable and flexible material created via the tanning of putrescible animal rawhide and skin, primarily cattlehide. It can be produced through different manufacturing processes, ranging from cottage industry to heavy industry.-Forms:...

 bottoms covered in grease

Grease (lubricant)

The term grease is used to describe semisolid lubricants. Although the word grease is also used to describe rendered fat of animals, in the context of lubrication, grease typically applies to a material consisting of a soap emulsified with mineral or vegetable oil...

 and the shells had concave, longitudinal seats. The athletes could then use their legs to slide along the seat, adding the power of their legs and letting them greatly lengthen the stroke. This eventually led to the modern sliding seat, mounted on rollers, which allows nearly frictionless movement of the rower's body.

Sliding rigger

The same advantages may be obtained by fixing the seat and mounting the outriggers on rollers. Now the athletes body mass remains stationary and the boat doesn't pitch bow to stern nearly as much. This improves the boat speed significantly.
The disadvantage is that this arrangement may result in blisters on one's buttocks and in the risk of sliding off one's seat when exerting too much explosive force at the beginning of a race
.
In April 1877 Michael Davis of Portland Maine applied for a patent for a sliding rigger/foot-board with fixed seat.
In 1981 the German Peter-Michael Kolbe

Peter-Michael Kolbe

Peter-Michael Kolbe is a German rower and is one of the greatest single scullers ever. And, with the possible exception of Australia's Stuart Mackenzie, the greatest to have never won an Olympic Gold Medal...

 won the FISA

International Rowing Federation

The Fédération Internationale des Sociétés d'Aviron, or FISA for short, is the International Rowing Federation which is the governing body for international Rowing. Its current president is Denis Oswald...

 World Championship using a sliding rigger. In August of 1983 FISA banned the use of the sliding-rigger, presumably because it was thought to be more costly than sliding-seat boats.

Boat classification

There are a large number of different types of boats. They are classified using:

• Number of rowers. In all forms of modern competition the number of rowers can be 1, 2, 4, or 8. Although they are very rare, boats for other numbers of rowers do exist (such as the 24 person Stämpfli Express
  Stampfli Express
  The Stämpfli Express is a rowing boat for 24 rowers and coxswain made by Swiss manufacturer Stämpfli. The boat can be rigged for either 24 scullers or for 16 scullers and 8 sweep rowers....
  
  ). In the 19th century, there were often races with 6, 10 and 12 rowers per boat.

• Position of coxswain. Boats are either coxless, bow-coxed (also called bowloader
  Bowloader
  A bowloader is a crew shell in which the coxswain lies semi-supine in the bow, as opposed to the normal seated position at the stern.Bowloaders are often seen as coxed fours and also coxed pairs...
  
  s), or stern-coxed. In coxless ("straight") boats, a steersman is responsible for steering by either use of a mechanism connecting one of his shoes by wire to the rudder—the swiveling of the shoe turns the rudder, or by using a hand controlled string, called a tiller rope, which is parallel to the gunwhales or the boat, and controls the rudder in a similar fashion. Singles and doubles do not employ a rudder in competition; the oarsmen steer by increasing or decreasing pressure on one scull or the other. In competition, bow- and stern-coxed boats may race one another.

Although sculling and sweep boats are generally identical to each other (except having different riggers), they are referred to using different names:

• Sweep: straight pair (2-), coxed pair (2+), straight four (4-), coxed four (4+), eight (8+) (always coxed)
• Sculling: single (1x), double (2x), quad (4x), octuple (8x) (very rare in world class, and always coxed)