The downed Nazi plane and bodies can be clearly seen in the water. But Loch Ness is filled with thick particulate peat, and underwater visibility is about five feet.
The water of Loch Ness is a deep brown, like a dark tea, from the tannins in the surrounding peat. It is not blue or green, or as easy to see through as it is frequently on this film.
There are no islands on Loch Ness.
Around 55 minutes in, as "Nessie" is moving through the forest, the crew controlling it are clearly visible in the bottom left corner of the shot.