Markie,
I've never heard the term "Tidal Grid" used before, but I surmise that you're referring to a shallow slip area. I'm pretty sure that the O'Day keel can take the weight of the boat, but if you have bottom paint on your keel, it could wear off with two groundings a day. Then you'll get Barnacles on the bottom of the keel which can slow your boat right down. Also, this boat doesn't have a kick up rudder and you have to take into consideration what might happen if it grounds out. Could it cause damage to the pintles and gudgeons, or even the rudder? Myself Markie, I would rather have a mooring than a slip any day just as long as the marina provides a live dock where I can load up friends and gear. I use a 9' kayak to get out to my mooring. It fits nicely in the bed of my truck under the cap, kitty-cornered. It even stays in my truck all through the winter. I tied a 15 or 20' line to the bow of the kayak and run it behind the lifeline rail and back to a winch when I need to get on and off my 22. I can stand right up in my kayak while holding on to my boat. A mooring is cheaper, and you sail off it or sail to it with a little practice. The kayak can be towed right behind your boat with no drag whatsoever.
Ahoy!
Joe