Andre Vaudin has been diving for 35 years, most recently for scallops near Beaucette Marina.
Divers are required to display a blue and white flag, known as Code Alpha, to notify sea-goers that a person is beneath the surface and to avoid the area.
But Mr Vaudin said most boaters do not know the meaning of the flag after having two vessels pass over him or very near him in the past six weeks.
‘I was on the surface waiting to be picked up when a 20ft motor cruiser passed above. The boat that was picking me up had to stop coming towards me. When there is a diver in the water, if that hits you you’re dead.’
He said one boat was going at a speed of at least 30 knots.
‘The vast majority don’t even know what a white-and-blue flag is.
‘It doesn’t make me hesitant to go out, we take our chances on the way to work in a car every day. But it could put off a less-experienced person for life.’
Head of port operations Jerome Davis said mariners should be aware of all single-flag signals.
‘The code flag Alpha, when flown on its own, means “I have a diver down – keep well clear at slow speed.” It is one of the most commonly-used signal flags but it is advisable for mariners to have a working knowledge of all single-flag signals.’
The flag is from the International Code of Signals, which are internationally-recognised signals for code, allowing mariners to communicate with each other about the safety of navigation and related matters.