tank choice & process
There are many factors that come into play when choosing a tank that is right for you.
Powered or Unpowered?
Both kinds are useful, but different. Suggesting that only one is of value is like saying only free weights are good, and ergometers are bad. We recommend both, think both can be useful, and think that decisions about which to install should be made with very careful consideration of the plusses and minuses of each.
Sometimes it is simple budget decision: Usually powered tanks are more expensive than unpowered. In some cases, for very fast tanks, they can be considerably more expensive. Faster tanks (powered) provide a very good simulation of rowing in both the way it feels to the rower, and the way it looks to the coach.
In moving water tanks, and especially in a fast tank, normal oars can be used, or they can be slightly cut down, and rigging (and arc) remain similar to a racing shell. Water speed can be much closer to actual rowing speed. Catches and finishes, and the timing of power application are much like on-water rowing. In some cases, this can mean more time spent in the tank. That is, when the coach has a powerful tool like this at his or her disposal, it changes the calculation about when to go out on the water, and when to stay in the tank.
Dead water tanks are cheaper and simpler. The rigging needs to be altered to get anywhere close to a realistic feel, with a considerably longer inboard; so the rowing arc is less like a boat. In dead water tanks the oars move much faster than the water. Shafts are shortened, blades reduced, inboard increased, and spread increased to allow the oar to slip—since the water never “gets up to speed.” The simulation works for leg drive and learning to get power on, but the catch and finish angles are less realistic, and with the water almost at a standstill, the catch is heavier, but not as well simulated, likewise the finish; there is no “crab.”
Also, since the water is moving very slowly compared to the oar, there are waves and sloshing. These don’t prevent the athletes from getting a workout, but contrary to what you might think, dead water tanks are often rougher and noisier than moving water.
Can you use a moving water tank with the motor off? Yes, in fact one of the great things about tanks, whether powered or not, is that they give athletes a place to work on water feel and technique on their own, without the pressure of seven athletes watching and being thrown off by their efforts at adjustment. There is not much difference between an “athlete-powered tank” (which won’t be moving much with just one rower), and a powered tank with the motor off (which won’t be moving much with just one rower). Basically, the dead water tank, with its longer inboard and short outboard, will feel lighter, but have shallow catch and finish angles. The powered tank, turned off, will be heavy, but catch and finish angles will be close to what is in a boat.