Oops. Here are the correct links.

Overshot water wheel

[img]http://mw.concord.org/modeler1.3/mirror/mechanics/overshotwaterwheel.gif[/img]

http://mw.concord.org/modeler1.3/mirror/mechanics/overshotwaterwheel.html

Undershot water wheel

[img]http://mw.concord.org/modeler1.3/mirror/mechanics/undershotwaterwheel.gif[/img]

http://mw.concord.org/modeler1.3/mirror/mechanics/undershotwaterwheel.html