What we did
I haven't done any open water sailing yet, but my wife and I saild south and back on the ICW on the Texas coast(about 120 miles each way). Going down, we tied off at a pier and slept tied off, but coming back, we sailed straight through. Going south, we decided on 2 hour shifts, but only loosely followed them. Coming back, we decided on 2 hour shifts until 8pm, and 4 hour shifts from there, with me taking 8-12, her taking 12-4, and me taking 4-8. That worked for us because I'm a night owl, and don't normall get a lot of sleep. The 8-8 shifts were strictly followed. Both ways, each of us would frequently take 2 hour naps during our off-watch time. However, sometimes we'd stay up and talk, play with the dolphins, whatever. Anything to get away from the tiller for a break. We now have an autotiller, and I suspect we'd do 4 hour shifts if we were on the open water.
