Sidney Wilson was in the city with his wife Janet when they decided on a cruise down the loch to take in the sights.
And it was as they approached Urquhart Castle that he ended up taking this intriguing photograph.
Sidney, who comes from Nottingham, said: "I was just taking pictures of everything as we sailed down the loch.
"As we approached the castle, two power boats appeared and circled us at speed, leaving a large wash in their wake.
"Thinking that it would make a good photograph, I fired off two quick shots and on the second, there appeared to be something in the water."
After enlarging the image, Sidney could swear he could see a head and fin in the boat's wash.
"After showing the image to staff at the National Hotel in Dingwall, they advised us to contact the Highland News," he added.
The sighting took place on Tuesday, March 27.
The earliest claimed reference to Nessie is taken from the history of St Columba in which it is said he saved the life of a Pict who was being attacked by the monster.
The first modern sighting occurred on May 2, 1933. A report in a local newspaper claimed a Mr and Mrs John Mackay saw "an enormous animal rolling and plunging on the surface".
Most sightings take place between March and September – a coincidence cynics claim coincides with the tourist season.