The two workers said they had seen the other-worldly objects entering the sea at Wilsthorpe Beach, near Bridlington in East Yorkshire.
Paranormal investigator Paul Sinclair tells their story in a new book he is penning about the Wilsthorpe incident, which has been branded Britain's new Roswell due to the mysterious military activity seemingly connected to UFO sightings.
The two men were working for the owner of a bait shop at nearby Bridlington Harbour when it happened, according to Mr Sinclair.
He said: "They were at Wilsthorpe digging in the mass tides. It was an area where the bait shop owner told me they had reported seeing triangles going into the sea.
"On this day they were surrounded by soldiers with guns who asked them where they were going and what they were doing.
"They were interrogated, and the lads were a bit off with them, but the soldier said 'if you are not off the beach by the time we turn around you will be going nowhere, because we will arrest you'.
"The bait diggers said they hung around looking from the cliffs and the military men had what looked like metal detectors and were going up and down beach."
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