This reminds me of a story a police diver told the group one night. The police diver was the one who had arranged these "Tuesday night dives." The more people in the group, the less each had to pay the captain to take us out.
So on the way out of the harbor, the police diver told us about a recent incident where an intoxicated party-goer stepped off the fantail of the booze cruise ship and drowned. The police divers had to go down and look for the body before it bloated from decay and unceremoniously floated to the surface.
The water in the harbor is cloudy for various reasons. One could barely see the other divers just an arm length to the left and right. So the divers would swim along holding a knot in a rope, cutting wide swaths like a lawnmower. One of the group asked the police diver, "If the water was that cloudy, how did you find the body?"
The police diver smacked his forehead with a palm, "You run into it."