bluebrew
Here are a couple of video links to my towboat. You can hear the iPod play the horn sound. A towboat is alot easier to build than a sternwheeler and you can do more stuff with it like get pushy, but only when they need it. It is shallow draft but I have a large battery low in the hull for ballast.
http://www.youtube.com/watch?v=shl7J0drIXQ
http://www.youtube.com/watch?v=28HaC65Va5g&feature=user