Re: shoal draft keel vs regular keel
BobPerry is correct. Shoal draft is a "requirement" of water, not an option of preference, well, it IS an option if you are a trailer sailor (like me).
Honestly if you sail mostly shallow water, you can snicker at the deep fins, who can't get where you go! However, they'll be snickering at you when it comes to open water, and you need to sail close to the wind!
Like I said there is a special exception to this rule, and that's trailering, where it's dictated not by how deep the water, but how steep the ramp for launching (yourself)... a shoal draft keel is way easier to trailer launch than a deep fin! Some ramps don't even go deep enough for a trailer to get a deep fin launched! hell some aren't even deep enough for the shoal draft keel (stink pot ramps).
There have been many attempts at "fixing" the sailing performance of a shoal draft keel, like the scheel keel (see Compac-Yachts), and shoal/centerboard (oday's and tons others), and like mine, wing/shoal (modern hunter/catalinas) with various degrees of plusses and minuses. Generally speaking though, they all have varying problems with sailing close to the wind.