BY VOLKER NOLTE | PHOTO BY PETER SPURRIER
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When it comes to rigging changes, remember that rowing fast depends on two things: force on the blade and the time that force acts on the blade. Blade force is the only force that can propel the overall system—rower and boat—and together with the length of time it’s applied changes velocity. Rowers strive to generate high blade force over a sustained period of time.
Blade force is a function of the interaction of blade and water. Blade force can be generated only if the blade moves relative to the water, and its magnitude is directly correlated to the velocity of that movement. So if rowers want to increase blade force, they need to move the blade faster through the water, which in turn reduces the time that the blade interacts with the water.
This means rowers must have the equipment to create good blade speed in the water while generating the necessary force on the handle. To accomplish this, we make the inboard short enough so that handle velocity translates to blade velocity while keeping it long enough for rowers to produce the necessary handle force to counteract blade force.
Another factor in determining the best inboard length is the geometry created by the inboard rotating around the pin. It must fit the anatomy of the rower so he or she can muster large handle forces over a long path. This is achieved by choosing an appropriate span for a given inboard, which is why inboard and span are always closely related. For example, the inboard is typically 30 centimeters longer than the spread in sweep, and in sculling the length of the two inboards together is regularly 16 centimeters larger than the span. So if you change one of these measures, you must change the other, too.
Selecting the best rigging measurements is a complex undertaking, and there is no simple formula that can be applied universally. All the following factors have to be recognized: blade shape and size; boat class; size and power of the rowers; technical skill of the rowers; wind and water conditions; length of the race, and more. No wonder coaches hesitate to change rigging measurements after they’ve found a set of numbers that seems to work.
For example, the numbers 88/288/160 centimeters for inboard/total scull length/span are very common for single rowers, and you find them all over the world. Weren’t these the numbers that Mahé Drysdale used to win an Olympic gold medal?
Indeed, those were the measurements used by one of the best scullers ever. What coaches often forget is that this rower has been an outstanding specimen in size and fitness, and we don’t usually find such rowers in our clubs. Should we not think twice about using the same numbers for a lightweight junior?
Rigging measurements should be customized to the individual, just as bicyclists change gearing depending on speed, grade, wind, etc. Compared to bicycling, do we change enough gears in rowing, and how many centimeters do we have to move measures so that they have a significant impact?
Let’s focus for now only on changes to inboard and span and discuss specifically the rigging changes in sculling. All the information presented applies to sweep rowing as well, though certain things (e.g., overlap of inboards) are different.
If you lengthen the inboard by one centimeter and leave everything else the same—that is, you keep the length of the outboard and span the same—you shrink the catch angle of the oar by a minimal half a degree, but you lengthen the lever by 1.1 percent, so you reduce the handle force accordingly. The increased overlap of the handles requires a little more technical skill, and the lighter handle force is just noticeable. Such a change is appropriate at a regatta with some headwind as long as the water is not so rough that the increased handle overlap becomes a problem. Changes more minor than one centimeter would have a scarcely noticeable impact on stroke length and handle force. Larger changes of the inboard would necessitate appropriate changes in the span.
Changing only the span is advisable solely for technical reasons: helping a rower manage the overlap, for example, or shifting a sculler’s arc more toward the catch (enlarging the span will necessitate moving the foot stretcher to the stern, which in turn will increase the catch angle while decreasing the finish angle) or the finish (reducing the span). Adjusting the span by only two centimeters will produce noticeable changes, but such a change affects only the so-called “dynamic gearing” while the “static gearing” remains the same. Changing only the span takes considerable time for rowers to get used to.
Changing the inboard and span in tandem while maintaining outboard length influences the load a sculler experiences dramatically. Changing the rigging from 88/288/160 centimeters to 86/286/156 centimeters increases handle force by 2.3 percent for the exact blade force and increases the oar arc by about two degrees, which makes the dynamic gearing heavier. To illustrate the difference, shortening the overall length of the sculls to 282 centimeters would be required to maintain the load of the original rigging.
Bottom line: There are many options for influencing the load a rower experiences. What measures should be taken depends on the individual situation. Is a short-term measure necessary, such as when the wind changes at a regatta? Or can we work with rowers over an extended period of time to improve their effectiveness? The goal of the rigging change should be identified clearly, while realizing that fiddling around by mere millimeters will not really help.