Cox box
A Cox box is an electronic device used in competitive rowing that combines a digital stroke rate monitor and elapsed time readout with a voice amplifier. Although the term "Cox box" is commonly used as a generic descriptor of this type of device, the name 'Cox-Box' is a registered trademark of Nielsen Kellerman, one of the several companies that manufacture this type of unit.
Use
Mainly used in Eights and Fours the read outs are used by the coxswain to monitor the performance of the crew and manage the race. This is of particular importance in head (time trial) races where the performance of other crews cannot be easily gauged.
The amplifier is linked to one or more speakers along the boat making it easier for the crew to hear commands, this is particularly important for the rower in the bow seat as they are furthest away. The coxswain typically wears a headband-mounted microphone, which is attached by a wire and quick release to the cox box.
History
Before the development of the cox box a megaphone strapped to the head of the coxswain was used to make the cox easier to hear.
Strokes Per Minute (SPM) or Rating
Almost all modern cox boxes have a Liquid crystal display, showing the Strokes Per Minute (SPM). On most Cox Box systems, a magnet is positioned under the Stoke's seat. As the rower moves up the slide (moving forward to prepare for the next stroke), a measurement is taken, and fed to the cox box. The stroke seat (first rower in the stern) sets the rate of rowing for the whole crew so this is very important. The Cox Box also usually features a timer which can be stopped, cleared, and reset, along with a stroke counter. For early morning or late evening rows, the Cox Box is also eqipped with an aqua colored backlight.
Relevance of Stroke Rating
The stroke rating is extremely important when competing in long race events, usually called head races. An excessive stroke rating would mean that the strokes of the rowers will be less than perfect as they are hurried and this will unbalance the boat. If the balance of the boat is not good, then the rowers will not be able to cover the blade properly, meaning that a smaller amount of water would be displaced, moving the boat a distance which would be less than that of a boat which is perfectly balanced. If the stroke rate is continuously excessive, there is less of a chance of winning the race at all as distance is lost every stroke.
For example: If 400 strokes are taken in 3 kilometre head race, and due to poor technique the boat loses 1 m a stroke they will fall behind around 400 m compared to a perfectly rated opponent crew in the same time period, even though the rowers of both crews have put the same amount of effort into taking the strokes.
An excessive rating will also cause the crew to tire too quickly, as a result their technique may suffer further.
Rowing is not just about the sheer power, but also about technique and precise timing, this is easier to manage using a Cox Box.