A Dublin Bay sea mist that lay in the middle of the bay most of the morning had enveloped most of the south shore by lunchtime, reducing visibility down to 50 metres or less at Dun Laoghaire Harbour.
The morning had seen a large number of different types of pleasure craft enjoying the bright sunshine and calm conditions.
Met Eireann had forecast Northeast or variable force 3 winds with some patches of mist or fog.
There were groups of different dinghy classes, sailing cruisers as well as fishing boats, jet skis and motor cruisers all enjoying one of the first weekends of 2021 afloat.
Canoeists and paddleboarders and rowing boats hugged the shore at Scotsman's Bay as the mist grew thicker.
There were plenty of swimmers and day-trippers sampling the admittedly very cold February waters of just 7 degrees.
The extent of the mist meant that by 2.30 pm there most boating activities were kerbed with the fog lifting just after 4 pm.