Understand what three main buttons do and you'll rule practice.
Understand what three main buttons do and you'll rule practice.

Back in the day, a coxswain wore a megaphone strapped to his face in order to be heard by the crew, and used a mechanical stop watch and rate watch to manage workouts and races.

In the early 1970s, chemist Richard Kellerman saw enough distracted coxswains run into things on the water that he was convinced there must be a better solution. Kellerman worked in his basement with physicist Paul Nielsen to develop the first CoxBox, which packed multiple functions into one unit. They built it in a 4-inch diameter sewer pipe (it was cheap and the right size) and today every coxed boat is built with a 4-inch diameter cup for storing a CoxBox.

Today, if you find yourself in the cockpit of an eight or four, you’ll likely have a CoxBox (made by Nielsen-Kellerman) in-hand to help you monitor the performance of your crew during practices and races. The simple three-button design allows coxswains to keep tabs on important data including stroke rate, stroke count, and elapsed time. Plug the CoxBox into your boat’s internal amplification system, strap on your headband-mounted microphone and you’re linked to your crew and ready to take charge.

I teamed up with NK Rowing Brand Manager Emma Overton to answer coxswains’ most common questions about the CoxBox’s functionality:

How do I clear the screen?

To clear the screen, first make sure the timer is stopped (if it’s running, press the START STOP button to stop it), then press and hold the STORE SPLIT button. When you press the STORE SPLIT button, “C L E A r” will appear on the screen; keep pressing until “C L E A r” disappears and you see “00:00.0.”

NOTE: Clearing the screen also clears the memory.

How do I start the timer?

After clearing the screen, the timer is zeroed and stopped. Press the START STOP button once. “READY” appears to the right of “00:00.0” and “STOP” disappears. Now the timer will start when stroke seat begins rowing. (If you want to time a drill that starts with the stern pair out, or arms only, simply have the stroke move his or her seat up and down the slide until the timer starts.)

NOTE: The timer is triggered when the magnet underneath stroke’s seat passes over the sensor on the boat deck. This keeps the coxswain’s hands free for steering at the start of a piece, and provides more precise timing when rowing side-by-side with other boats.

Timer, stroke rate, and stroke count will keep running until stopped. The timer will run to 59:59.99 then roll back to 0.

How do I record the information I see on the screen?

The CoxBox automatically records the stroke rate every ten seconds while the timer is running. You can record a snapshot of the information you see on the screen, including exact time, stroke rate and stroke count for the piece, without stopping the timer by pressing the STORE SPLIT button while the timer is running. The screen will freeze for five seconds so you can read it, but the clock will continue to run internally. A snapshot of the information on the screen also gets recorded when you stop the timer, but all the memory is deleted if you clear the screen.

NOTE: The stroke count will run to 999 then roll back to 0. The stroke rate will be stored in memory automatically every 10 seconds for 59:59.99 Stroke rate information is an instantaneous snapshot, not averaged.

How do I view the recorded information?

To view the recorded information, first make sure the timer is stopped (if it’s still running, press the START STOP button). Press the RECALL MEMORY button to access the memory, then the STORE SPLIT button to move forward through the piece in ten-second increments, or the RECALL EXIT button to go backward through the piece. Press and hold the RECALL EXIT button to get back to the timer.


Go behind-the scenes at Nielsen-Kellerman with Coxing Magazine’s article “Inside the CoxBox.”

Do you have more questions about the CoxBox? Email rachel@rowsource.com, or visit www.nkhome.com.