Two faint blips on a sonar screen have led a pair of modern day shipwreck hunters to the final piece of a 200-year-old puzzle.
HMS Colossus, one of Admiral Lord Nelson's warships, sank in waters around the Scilly Isles while sheltering from severe storms on her return from a keynote battle.
Parts of the massive ship carrying treasures belonging to the husband of Nelson's mistress, the notorious Lady Hamilton, have already been scooped up and preserved.
However, Colossus' giant anchor has never been found – until now.
Todd Stevens and Robin Burrows had decided to take a fresh look at the evidence surrounding where exactly the gunship had floundered.
They examined tide times and accounts of the wind as the raging storm which forced her to seek safety in the waters of Scilly ebbed and grew again, realising that previous searches must have been in the wrong place.
After scouring the seabed, they came across a couple of anomalies on a sonar scan which could have easily have dismissed as seabed rubble, so Mr Stevens decided to dive down and take a closer look.
"It was amazing," he said.
"I went down and I could see two tips sticking about two feet out of the sand.
"I started digging around them and I just knew straight away what it was.
"I came up and went back up the ladder and said to Robin, 'You'd better get your camera out.'
"I said, 'It's an anchor, but not just any old anchor. I think it's what we have been looking for'."
Mr Burrows, said it was a truly exciting find.
"You run your hand along this anchor and it's huge, 20 feet or so.
"Then you think that the last time this was dry was back in 1798. It's a really amazing thought."
Mr Stevens, who lives on St Mary's and is a prolific chronicler of wrecks, is already responsible for locating numerous other remains, including a ship suspected to have belonged to Sir Walter Raleigh.
But the Colossus holds a special place in his heart as back in 2001 with his wife Carmen he uncovered the spectacular carved wooden figure of a neo-classical warrior which had adorned the stern of the ship.
"The Colossus has been a big part of my life.
"Everything else from the ship has been found, the guns and the wreck and how it is spread out, but the only thing that was missing was the anchor.
"It was the final piece of the jigsaw and to find it is quite exciting."
The Colossus, a 74-gun ship launched in 1787, wrecked off Samson, one of the Isles of Scilly, as she was returning from serving with Nelson's fleet at the Battle of the Nile against Napoleon's fleet.
More than 200 sailors were on board, but thanks to careful steering by her captain all were able to escape and the only fatality was a man sent back to check the depth of the water.
She was also carrying a hoard of valuable Etruscan pottery belonging to Sir William Hamilton, husband of Lady Emma, the famous beauty and mistress of Nelson.
More than 30,000 pieces were recovered from the wreck, most of which are at the British Museum for safe keeping.
But Mr Stevens said his pleasure came from locating the wreck and tracing its history, rather than discovering treasure.
"I know it's not like we have found gold bars and that some people won't be interested.
"But to us it is of huge interest and it is a marvellous piece of history."