NZSSRA
_{est. 1967}

Levers

A lever uses effort (the rower) on an object (the oar) braced against a fulcrum (the water/boat) to shift a load (the boat/water). According to FISA, boats must be propelled by a second order lever, which is one with the load in the middle. From the shore that is what rowing looks like:

• the rower puts in their effort at the handle end of the oar; and
• the water stays still, so it is the fulcrum, at the blade end of the oar; and
• in between, at the pin, the boat is the load that is being shifted up the course.

However, from the rower's perspective there is a first order lever in action, which is one with the fulcrum in the middle:

• the rower puts in their effort at the handle end of the oar; and
• the pin does not move so it is the fulcrum; and
• the load is the water being shifted back towards the stern of the boat at the blade end of the oar.

Fortunately, as far as gearing is concerned for coaches, it does not matter which type of lever is in action because the effect of changing the ratios is the same.

levers and gearing: pin position

Light gearing	blade >------< pin <-----------------------> rower
Heavy gearing	blade <-----------------------> pin >------< rower

A lightly geared boat requires more strokes to move the same distance as a heavily geared boat but the strokes for a heavily geared boat are harder to make.

Because it is much easier to look at gearing from the rower's perspective (instead of a shorebound FISA official perspective) we will treat oars as if they are 1st order levers. This also means the arcs traced out by the oar and the limitations on those arcs are easier to follow.

Arcs

With a 1st order lever you have two complimentary arcs traced out by the ends of the oar rotating around the pin. Gearing is determined by the ratio of the distance travelled by the blade of the oar (outside arc) to the distance travelled by the handle of the oar (inside arc).

Arc effect

Arcs	outside arc (((	blade >---------------------> pin <----< rower	))) inside arc

The outside arc affects the propelling force of the oar on the boat.
The inside arc affects the biomechanics of the rower.

When looking at the angle swept out by the arcs there are a couple of considerations.

• The oar is at its most efficient when it is perpendicular to the boat; and
• Rowers have to be able to hold the oar and apply useful pressure to it throughout the arc.

In principal, the angle of the arcs will be limited to the rower's inside arc and gearing is simply a matter of changing the length of the blade and/or inboard (distance from pin to handle). However, in practice, changing the inboard can involve changing the size of the spread and will usually affect the amount the inside arc overhangs the boat's keel. Those changes have the following effects:

• Tightening the spread generally increases the angle swept out by the arcs because it makes it easier for rowers to arc the blade behind them at the catch; and
• If the inside arc is too far away from the keel (most historians allow 30cm) this can cause problems with rowers leaning out of the boat to complete their arc [depending on the technique used].

Finally, to add to the confusion, each rower in a crew will have an optimal arc that depends on that rower's height, strength and ability, the speed of the boat and whether the coach has set the boat up from the catch or the finish (backstop). Then, for the more advanced coach, the idea of the rowers arcing their oars in unison is what rowing is all about.

For the average school coach, faced with sharing oars and equipment, similar arcs are achieved through the placement of the foot stretcher and the compression of the body and legs at the catch - then standard measurements are used for the oars. For coaches with the plant and/or the inclination it is possible to change the leverage for each rower to ensure individual rowers of different shapes and strengths are able to arc together as a crew.