The tub pictured here is what I assembled for a customer a few years ago, http://www.cedartubs.com/images/measurments/5-metric-standard-large.jpg, I am using this as a guide for my own design. It implemented the cvg western red cedar and the canoe joint, the bottom was rabbited into the 2x6 - 48" tall staves and secured outside with the SS banding. I have easy access to white oak that is 3/4 thick and considering the attempt to fabricate the tub with this material, I have a concern if the oak would be strong enough in that thickness and I realize that my stave to bottom joint depth would only be about 3/8" deep dado. However, rather than purchasing 6/4 oak to make the staves I am also considering using a waterproof glue to glue up the oak I have to make 1 1/2 " thick staves. The canoe joint on the cedar has been watertight thru several seasons, drainings and refills. If I could afford the cedar I would do it with that material but it really is prohibitive. The Doug fir option mentioned by other posters is intriguing. I was not planning on putting any sealer on the interior of the tub. So it goes back to how the different species of wood would resist rot and respond to wet and dry conditions. well lots of things to consider. Thanks again for all your input! Once it warms up in my unheated shop I am going to start the project and hope to be soaking my mid May. I will post pictures and probably be looking for more input as I begin sizing up my materials.