Here you can see all the nice features of the washtub bass. Note especially the inlaid walnut fingerboard and the birch log legs and hand carved toenails.
I tune the string to a low F. I'm able to play a little more than an octave on the fingerboard. I can push the whole fingerboard forward which lowers the pitch and get down to a low Bb. I'm always adjusting the pitch to stay in tune. Kind of like playing a huge slide whistle.