Here is a link that shows a Google Earth view of the area the diver was found by the fishing boat in. It's called Dolphin Point:
Dolphin Point / Dolphin Point, Cayman Islands (general), Cayman Islands, North America
I have not dove this
particular site, but I have dove many of the other sites in close proximity.
Note that the word "site" is usually designated by some sort of a bouy or marker at a specific location. Keeping that in mind someone could dive off the area called Dolphin point without actually being at the "dive site" Dolphin point.
When you zoom in and view the map of this area, the light green area is normally a hard coral bottom, covered with thin layer of sediment and plants. IME, this area typically ranges from 10-70' and may be punctuated with shoals or coral heads.
The dark line between the lighter blue area and the greenish area is where the mini wall starts. The mini wall starts as shallow as 40' in places and drops off to about a max depth of about 120' although 70-90' is probably about average.
The light blue area in between the dark blue/black and the greenish area is typically sand flats. The sand flat can be a narrow strip, or a hundred+ yards wide, depending on the specific area. The flats can also contain coral heads and shoals.
The dark blue area is the main wall. The top of the wall typically starts around ~120' and is usually pretty dramatic. It does have a
slight slope to it for the first 50-100' before becoming more vertical.
I'm not familair with the
particular site that this group was at, so I can't comment on the accuracy of a hard bottom at 140'. In my experience, it would be unusual to find the bottom that deep without being close to the actual wall itself. If they were not on the wall, then its is likely that the diver would have to cross a fairly large sand flat before hitting the main wall and being able to go deeper.
If I can find depth charts for this specific area, I'll add them later.