The family of a 12-year-old girl who drowned off Bournemouth beach have told an inquest that they questioned the conduct of the “very young” and “panicked” lifeguards who took 50 minutes to find her in shallow water.

Sunnah Khan, 12, and Joe Abbess, 17, drowned last May, and eight other people were treated by paramedics, after they were caught in a rip tide next to the pier at the Dorset seaside resort.

At the inquest into their deaths on Tuesday, Stephanie Williams paid tribute to her “kind, funny, reliable, smart and incredibly beautiful” daughter, Sunnah, and criticised the response of the lifeguards on duty. She said: “Why did it take 50 minutes to locate Sunnah in less than 5ft of water?”

In a statement read to the court, Sunnah’s father, Asim Khan, said his daughter “was like the sun, always shining”. He said the lifeguards on duty were “mostly very young” and “looked like they didn’t know what to do”.

Khan said he was on a family day out with Sunnah, his sister, Rehana Khan, and two other children. After lunch, he said he remained on the sand with one child, while his sister took Sunnah and another child into the sea.

He said that after lifeguards had begun evacuating the beach he found his sister and the other child but realised that Sunnah was still missing.

When he raised the alarm with a lifeguard, which was about 20 to 30 minutes after the first person was brought out of the sea, he said that they “started panicking” and began searching for Sunnah.

“I understand it’s a big, busy beach and you cannot keep an eye on every person but people had to tell the lifeguards that people were drowning and none of them had noticed,” he said.

“I believe that all of the lifeguards that day were doing their best, however they were mostly very young, teenagers really, they all seemed panicked and looked like they didn’t know what to do.”

Vanessa Abbess, the mother of Joe, paid tribute to her “generous, loving, caring, hardworking and funny” son on behalf of herself and her husband, Peter. She also questioned the experience of the lifeguards on duty.

“We question whether the area of sea where Joe died should have been a flagged safe swimming zone and whether it ought to have been redefined as unsafe following a rip tide incident in August 2021” she said.

“We feel that Joe and Sunnah’s deaths, all casualties and the entire incident could have been preventable if the flagged safe swimming zone had been reassessed.”

She said that she fell to her knees and sobbed when she was told the news, and described seeing her son’s “peaceful” body in the hospital.

Dorset police had previously impounded a pleasure cruiser after the fatal incident and arrested a man in his 40s on suspicion of manslaughter. Coroner Rachael Griffin ruled out the involvement of the Dorset Belle – which ran trips from Bournemouth Pier – saying the boat was not a “causative or contributory factor” to the two deaths.

After consulting an expert as part of its investigation, the force said it had made the “evidence-based decision” that the movement of the Dorset Belle did not contribute to creating dangerous sea conditions during the incident. It said that the arrested man would face no further action.