We use the term “bunch of grapes” to describe a tightly-packed cluster of hard, round-looking targets, which might indicate the pile of amphoras often found in sunken wrecks.
The geological feature is typical of the bright returns from the front surfaces of stones or hills facing Diana.
The interesting thing to note in the image of the Eregli G wreck, besides the shape of the ship itself of course, is the pronounced black sonar shadow created by the parts of the ship which extend above the sea floor.
Diana is appropriately named after the Roman Goddess of the Hunt. Four transducers on the bottom of Diana emit the sound pulses responsible for the imaging on the "orange waterfall."