Criccieth water bike riders 'tried to capsize paddleboard'
Paddleboarders and kayakers have criticised water bike users who were filmed riding aggressively and intentionally splashing people.
A video filmed in Criccieth, Gwynedd, on Monday shows the water bikes circling an inflatable kayak which is showered with spray.
A paddleboarder who was knocked off his board said the riders seemed to be deliberately targeting others.
The Criccieth lifeboat was launched to intercept the bikers.
Crew members later spoke to them along with police.
Keith Allmark, deputy launch authority with Criccieth Lifeboat, said the behaviour was extremely dangerous and the people targeted had been subjected to "a lot of anxiety and stress".
James Curless, from Criccieth, was on a paddleboard with a friend when the water bike riders approached.
He said: "One of them tried to knock my friend off.
"He failed first time, so he did a turn and sent a huge wave towards us. Then they did the same to me before darting off towards an inflatable kayak.
"They almost seemed to come out of the blue deliberately towards us. It was a very stupid thing to do."
Paul Dixon, from Pwllheli, who filmed the video, said: "It was obviously deliberate - they were riding round and round the kayak for some time.
"It's strange if that's their idea of fun - it could have been very dangerous for an inflatable kayak."
Diane Jackson, from HM Coastguard, said it had received several calls about 16:40 BST reporting potential risk to people from the bikers in the water at Black Rock Sands.