Speedboat owners are being urged to wear "kill cords" to cut power to their engines if they fall overboard after a vessel careered on to Seaford beach.
The inflatable speedboat scattered people on Seaford beach
Sunbathers scattered to escape the speedboat which ran on to the crowded East Sussex beach on Saturday.
Solent Coastguard said the inflatable continued up the beach at high speed after the skipper fell overboard.
The Royal Yachting Association said a lanyard should be worn which stops the engine if the skipper falls overboard.
The other end of the cord is attached to the engine's ignition.
"It is essential that a safety lanyard be worn at all times," said Paul Mara, the association's chief power boat instructor.
The skipper of the rigid inflatable boat (rib) in Saturday's incident is not thought to have been wearing a kill cord when he fell overboard.
He was rescued from the sea by a passing yacht.
A spokesman for the Maritime and Coastguard Agency (MCA), which is investigating the incident, said someone could have been killed.
One of the families on the beach had to be treated for shock by paramedics.
Last month, vessels in Southampton Water were put in danger after a rib was left circling at full throttle for 40 minutes when three people were thrown overboard.
The MCA said the harbourmaster's launch and the RNLI lifeboat from Calshot attempted many times to bring it under control.
After three attempts the lifeboat crew managed to get a man aboard.
"There really is no excuse for users of fast open powerboats not to be wearing kill cords, for their own safety, and for the safety of other people," said MCA prevention manager Peter Brown.