The table on the left gives the speed of waves of different wave lengths in deep water. “Deep” in this context is not an absolute value, but is relative to wave length. The simple relationship starts to to breakdown when the depth of the water is less than 1/4 th the wave length. At that depth the bottom exerts sufficient drag on the wave to slow its motion and thus decrease the wavelength [equations and more about wave speed].
The Concept2 Model D Indoor Rowing Machine includes the excellent PM5 monitor that provides all vital data. It can display your workout performance in two ways. You can choose to see your workout in total distance and time, or as “splits”. Splits is a way of seeing how your pace is varying along two set points. Either way is useful, but splits give you more of a “real-time”, in the moment calculation of how you are doing.
One downside of the Waterrower for me are the footrests. Whilst they are perfectly adequate if you want to row in shoes, rowing barefoot, which is something I like to do, is impossible. The plastic is completely square at the bottom and has sharp edges that cut into your heels. I also found that my shoes get caught when trying to put them in and out of the holders, which is a bit irritating.
Outside of resistance type, we found the number-one arbiter of ride feel to be cord quality. Water ergometers tend to employ nylon cords, while air ergometers feature metal chains — a durability factor we anticipated would result in our favoring air. But while all three water rowers aced our expectation of smooth, high-tension strokes, perfecting the chain seems to be more difficult: Some tug with just a slight rumble, others feature bouncy, grinding chains that are incredibly loud, something akin to angry snoring. As for nylon, the best wind and unwind like elastic silk — no slack, no sound, no catching, just perfectly even tension throughout the stroke.
First of all, if you're considering rowing, just do it. It is by far the most enjoyable and beneficial exercise I have ever tried. I've made huge strides with both cardio and muscle fitness with the WaterRower, and it's so enjoyable I look forward to exercising each day. Yes, it is more expensive than most other rowing machines, but when you compare it to a lot of other types of exercise equipment, it's actually pretty reasonable. When you also compare the exercise benefit you get, it's a bargain.