I looked at Jet dock and several other floating docks at the recent Pensacola Boat show, for my 18 foot Century--about the same weight as the CD 22. According to the sales people, the boat would back off using its engine--but I wondered about that.
The major reason I didn't get one, was that they had to be taken out of the water during hurricanes--even in our well protected bayou. The points of attatchment seemed a bit flimsy, but if there is no surge or wake present I am sure that they would be fine. With a high tidal range, are they as useful as when there is minimal tidal variation?
I would put teflon slicks on where the C Dory rests--like bunks--and thus the C Dory would run on these, rather than the dock material. Of course there is the issue of marine growth fouling the float--not sure if it has to be scraped off on not. The sales people told me that it had to be pressure washed (bottom) yearly--this may be illegal to do in some areas. (Marine growth is "toxic" and "Hazardous" in some people's books--not mine.