As for getting underway from a quay wall or a dock... If the Current and wind are nil, push off with a boat hook. Any boat up to 50' should be easy to do so. We did this with Navy launches all the time.
Think on how you want to move away from pier side, especially if you have a bow sprite, stern overhang or exposed rudder and other delicate equipment hanging off your stern.
The name of the game is: No matter what kind of keel you have; Practice you landings and underways on flotsams, jetsams and protected pier faces. And train you significant other in doing the same. You may be incapacitated for some reason or other, and the family or friends will have to bring your boat in to the dock.