Any decent college crew already has a rowing tank that's kind of like the endless pool. There are some good pictures here:
http://www.durhamboat.com/TANK.HTM
The problem is that rowing in the tank only gets you so far. It's like training for a marathon on the stairmaster. It's better than nothing, but it's not the real thing.
The hard part about rowing (besides the blisters on your palms, gasping for breath, and those times when both legs fall asleep and you have to stumble around on the dock in your socks through the goose turds) is balance.
The boats balance OK if all the rowers put the oars in the water. It's when they lift oars up that the boat can flop to the left or right. If the ports each raise their blades a little, and the starboards all lower a little, then the shell is going to lean over to the left. It's kind of like balancing on a tightrope with a balance pole, except that four people are hold the left pointing half of the pole, and four are holding the right half.