Originally made from wood, shells are now almost always made from a composite material (usually a double skin of carbon-fibre reinforced plastic with a sandwich of honeycomb material) for strength and weight advantages. FISA rules specify minimum weights for each class of boat so that no individual team will gain a great advantage from the use of expensive materials or technology.
The WaterRower Club Rower has been designed for high traffic areas such as commercial gyms, studios, rehabilitation clinics, etc. Its black rails have been styled to prevent scuffing; other wooden components are finished in an attractive rosewood which are more resistant to soiling than the natural model. Each machine has been hand finished with Danish oil and urethane for protection. Wood has been chosen due to its marvelous engineering properties, primary amongst these is its ability to absorb sound and vibration enhancing the waterrower's quietness and smoothness of use. Ash, like all woods used in WaterRower construction, is a premium hardwood with incredible longevity and dimensional stability. For reasons of ecology, all WaterRower woods are harvested from replenishable forests. WaterRower Club Rower Black Rails have been styled to prevent scuffing, other wooden components are finished in an attractive rosewood which are more resistant to soiling than the Natural model.
I kayak (ocean and flat water, not river), so I was drawn to the WaterRower over a flywheel type rower (which I have used in gyms) because I wanted to hear the sound of the water, which I miss hearing against the hull of the boat during the winter when I can't get out on the lake. I also like the way the paddles engage in the water; it's a very smooth pull and release, and moving the mass of the water instead of a dialed down tension feels more natural. As someone else also commented, the seat (at least on the wood version) is incredibly smooth and solid; no wobbling at all. I generally listen to music on my Nordic Track ski machine, but with the WaterRower I am content to listen to the sound of the water; working out on this is somehow both energizing and calmingly meditative at the same time. In the event that you want to use it while watching tv (this is one use to which I wanted to put it), it is quiet enough to hear the tv without having to turn it up.