The squat yellow box, with its protruding arms and hoses, drips salt water onto the deck of the ship.
If you did not know any better, you might take the cuboid for a hardy piece of space junk - an old lunar module, perhaps - which had splashed down in the English Channel.
It is in the exploration business, as it happens, though its terrain is the bottom of the sea rather than the oceans of the moon.
It is a Remotely-Operated Vehicle (ROV) known as Zeus, which is dunked in the briny in order to examine the seabed for shipwrecks.
Man of War
The people behind Zeus claim that it has helped them to solve one of the great maritime mysteries of all time - and also to uncover a major threat to Britain's marine heritage.
Odyssey, a US-based exploration company, has found HMS Victory, the predecessor of Nelson's flagship, and the most formidable vessel on the high seas in its day.
The Ark Royal of the 18th Century, the Victory boasted the most powerful arsenal in the Royal Navy and was helmed by our then greatest man of war, Admiral Sir John Balchin.
But Balchin - and a ship's company in excess of 1,000 souls - went to the bottom in 1744 in a sinking which has never been explained. Her guns were never fired in anger.
It was believed that the wreck of the Victory lay off Alderney in the Channel Islands. But Odyssey found her 100 miles (160km) from her presumed resting place.
Many archaeologists have been convinced by the sheer size of the armaments captured by Zeus - and I do mean captured.
HD quality pictures
Not only does this $2m bathysphere transmit HD-quality pictures from the bottom of the sea - something Newsnight has difficulty doing from West London - but its robot arms are capable of lifting the heaviest cannon known to the Admiralty:
"It just sort of scoops them up in a mesh. This thing can knit," says a wondering archaeologist.
Newsnight joined the Zeus's mother ship, the Odyssey Explorer, as she embarked on her latest journey of discovery. As the eight-tonne Zeus was launched, the entire ship - a sturdy former mine-sweeper - canted on her side in the Falmouth spume
On board, delight at discovery of the Victory has been tempered by what Odyssey says is damage to this and other wrecks caused by fishing.
They say fishing boats are the "bulldozers of the deep", smashing watery burial grounds with their nets and scallop-dredgers, and scattering important artefacts for great distances across the sea floor.
These are some the findings of the first comprehensive study of shipwrecks in the Channel, to be published on Wednesday.
The raising of the Mary Rose, Henry VIII's ship, a generation ago, proved that there is huge public interest in this aspect of our island story.
And of course there is also gold in them there hulls - or so companies like Odyssey hope.
Their research operation costs thousands of dollars a day, and they defray their costs through salvage operations.
They are committed to sharing their research with the wider community, for scientific and educational purposes.
But some marine archaeologists are sceptical of their approach, and say there is a lack of evidence to support the claim that fishing is damaging shipwrecks.
That is also the view of the fisheries spokesmen we contacted. They accept that there has been some accidental damage but, as one Cornish fisherman told us: "We might lose our nets, or even our boats, if they get snagged on a wreck."
Watch Stephen Smith's full report on Newsnight tonight at 10.30pm on BBC Two.