has anyone fished from dock or shore with portable fish finder and if so, how does it work?

humminbird and a few others make a portable fish finder that works like others by identifying objects through sound waves. the ability to fish from shore comes from the transmitter thats casted by the fisherman and trolled over water surface and signals are sent to fisherman on shore who has a small reciever. has anyone used one of these devices???

Powered by http://answers.yahoo.com