Don't ever remember seeing a boat underbody with the rudder as deep or deeper than the keel . Even a full keel boat rudder attached will have the rudder a few inches above the keel. Still, running aground often bends the rudder shaft on spade rudder boats. It is less likely with a skeg because of the extra support that the skeg supplies. That's not guaranteed, however. A boat with a skeg rudder recently sunk in Florida
after it had a gentle grounding on a mud bar and the skeg ripped off. Full keel boats usually fair well in a grounding because of the length of the keel and strong support of the rudder at the top and bottom and often along its length.
As far as handling, spade rudder boats turn on a dime and usually will back with control. Boats with skegs are slightly less maneuverable but still pretty easy to control. Full keel boats can be a handful going both forward and back. My W32 would back reliably once she was moving in reverse then put the engine
in neutral. Had a pretty wide turning radius but never had an issue getting her in a slip. My Pearson
35 with it's shallow full keel with cutaway forefoot is a nightmare. It goes where it wants, when it wants in revcerse. I just put it in reverse and pray it goes somewhere I want. Sometimes it will swing in the direction I want but other times will end up backing who knows where and hoping to be able to put it in forward and turn in the direction I want to go before hitting something. Often takes several tries to get moving in the right direction. Going forward has better control but still a pain if the wind
is blowing into the slip. If the wind
is above 10k, the bow falls off as it reaches about 45 degrees to the wind will not continue turning. Have had that happen twice and, strangely, after a lot of backing and filling ended up backing into the slip.
I ran the small skeg'd Morgan
35 aground a bunch in the ICW
. Never had a problem as it was mud and kedged off from the stern. Having said that, practically every boat yard I've been in has a trophy spade rudder with a pretzel shaft. Think most of them get in trouble when they run aground going forward and current
, waves or a tow boat swivels them around the axis of the keel. Have gotten away from sailing in thin water
so haven't had much experience running aground recently. The one time I ran aground in a full keel boat, just put out a kedge anchor
and waited for the tide to lift
the boat off with nothing but a few scratches to show for it.