Tasmania’s marine safety authority says it is “amazing” no one was hurt when a jet ski crashed into a timber walkway near a Derwent Valley boat ramp on Saturday afternoon.

Marine and Safety Tasmania posted a video of the incident at the Millbrook Rise boat ramp at New Norfolk to social media.

“It shows a jet ski with nobody riding it scooting up over the pontoon, which is adjacent to the boat ramp, flying into mid-air across the length of the boat ramp and smashing into a timber walkway opposite the floating pontoon,” MAST general manager Peter Hopkins told ABC Radio Hobart.

“Only an hour or so before this happened there were children swimming on the boat ramp, an adult swimming on that boat ramp,” he said.

“It’s just amazing that no one was hurt.”

He said it appeared the throttle was stuck and the rider was not wearing a kill switch.

“If he’d been wearing a kill switch the motor would have cut out.”

Mr Hopkins said he could not estimate how fast the jet ski was moving, other than it was “in excess of 25 knots”.

Swimmers warned of dangers

Mr Hopkins also warned swimmers about the dangers of swimming near the Millbrook Rise boat ramp.

“We’ve seen people launching [boats] around people swimming on the ramp and it’s only a matter of time before there is an injury up there,” he said.

Mr Hopkins said there were “fantastic” jet ski operators in Tasmania and the Jet Sports Boating Club promoted responsible jet ski use.

“The majority of our complaints at MAST are about jet skis and the way they’re ridden – close to beaches, exceeding five knots amongst swimmers, things like that.”

–ABC