I burried my (former) Grand Cherokee up to the frame on a beach one time. I carry a bunch of recovery gear also, which was lucky since there wasnt another soul around for miles. Tried jacking it with my Hi-Lift, but it just sank in the soupy-muddy sand... so I had to resort to an old military recovery trick. I took my spare tire and burried it about 3' down and perpendicular to the Jeep about 20' behind it, then used it as an anchor along with my 30' log chain and Hi-Lift to winch the Jeep back about 10 feet to "solid" ground.

Good times!