How Does Rowing Work? Oars, Levers and the Longest Stroke

An oar is a lever with the fulcrum at the blade, not at the rowlock. When the blade is locked in the water it does not move backward through it, or only a little; the rower's pull on the handle levers the rowlock, and the boat attached to it, past the fixed blade. The oar's inboard section from handle to rowlock is about a third of its length and the outboard from rowlock to blade two thirds, so the handle moves a short distance with great force and the boat moves a longer one, and the gearing, the ratio of the two, is adjusted by moving the rowlock along the oar the way a cyclist changes gear. The blade slips a little, which is the energy lost to moving water, and a good stroke minimises it by locking the blade fully before the pull and keeping it covered until the end.

A stroke has four parts, and it is the legs that row:

• •The catch: the rower slides forward on a seat that runs on rails, shins vertical, arms straight, and drops the blade into the water
• •The drive: the legs push first, driving the seat back, then the back swings open, then the arms draw the handle to the body; about 60 percent of the power is legs, 30 back and 10 arms
• •The finish: the blade is lifted out and turned flat, feathered, to skim the surface on the way back
• •The recovery: the rower slides forward again, slowly, while the boat runs on under its own momentum, which is the moment it is moving fastest

The boat does not move at a steady speed. During the drive the rowers' bodies move toward the stern and the boat is driven forward; during the recovery the rowers slide toward the bow, and since the crew weighs several times the boat, their movement pushes the hull forward beneath them, so that the shell is running at its fastest while the oars are out of the water. A crew that rushes the recovery checks the boat; a crew that takes it slowly lets the hull run. The rhythm of a good crew is a long, sharp drive and a patient slide, at a rate of about 36 strokes a minute in a race, and the whole eight must move as one, since a rower who is early or late puts a brake on the boat and unbalances it. The cox, facing forward, steers, calls the rate and sees the race the rowers cannot.

A racing shell is built to be narrow, since drag on a hull comes mostly from the wetted surface and the waves it makes, and a long thin hull makes small waves; the price is that it is so unstable that a beginner cannot sit in one without capsizing, and the oars, resting on the water, are what keep it upright. The hulls were wood until the 1970s and are now carbon fibre, the sliding seat was introduced in the 1870s and the outrigger, which puts the rowlock outside the hull so that the boat can be narrower than the oar's inboard length, in the 1840s. Boats range from the single scull, one rower with two oars, to the eight, and sculling boats, with two oars per rower, are distinguished from sweep boats, with one, in which the rowers alternate sides to balance the turning forces.

Olympic races are 2,000 metres and take five and a half to seven minutes, which is the worst possible duration for a human body: too long to sprint on the stored energy of the muscles and too short to settle into the steady state of an endurance event, so that the rower runs the whole distance at the edge of both systems, with lactate rising from the first minute. Rowers have the largest measured aerobic capacities of any athletes and the largest hearts, and the sport's training, hours a day on the water and on the rowing machine, is famous for its monotony. Races are decided by fractions of a second after two kilometres, the boats overlapping at the line by the length of a bow ball, and the crew that wins is very often the one whose eight blades entered the water at the same instant for two hundred and twenty strokes.

Rowing moves a boat by levering it past a blade locked in the water, with the rowlock as the moving point and the legs supplying most of the force through a sliding seat; the stroke is catch, leg-driven drive, finish and a slow recovery during which the crew's shifting weight makes the hull run fastest. A long narrow hull, an outrigger and carbon fibre make the shell fast and unstable, timing between rowers decides races, and the 2,000-metre distance sits at the point where sprinting and endurance both fail.