A Bournemouth MP has called for a review of safety following the death of two youngsters who died after getting into trouble off the popular beach and called on police to clarify the circumstances to end "wild speculation".
The sightseeing boat, the Dorset Belle, which is at the centre of investigations, has been impounded by Dorset Police following the incident on Wednesday in which a 12-year-old girl from Buckinghamshire and a 17-year-old boy from Southampton died.
Another eight people were treated by paramedics.
A man aged in his 40s who was "on the water" at the time was arrested on suspicion of manslaughter and has been released under investigation on Thursday while police inquiries continue.
On Friday, the 49-year-old sea-going passenger boat Dorset Belle remains at anchor at Cobb's Quay, Poole Harbour, guarded by a police van.
According to the website Marine Traffic, the vessel had visited Bournemouth Pier, the scene of the tragic incident, at 4pm, just minutes before the first 999 calls were made.
Dorset Police has said that no physical contact was made between the swimmers and any vessel or jet-ski and those involved had not been jumping off the pier.
The force has declined to comment on any investigation into the Dorset Belle and refused to say what or if any vessel was involved.
Tobias Ellwood, Conservative MP for Bournemouth East, said: "There needs to be a review, the police are conducting their investigation, there needs to be a review of the circumstances to see whether any safety measures and protocols need to be upgraded to ensure this doesn't happen in the future.
"I encourage Dorset Police to clarify the general circumstances of this tragic accident to avoid further wild speculation and uncertainty for parents who may be cautious about going to any part of the beach, unclear of exactly what happened in this terrible incident."
The vessel's website states that it was purpose-built as a passenger boat to operate locally and could "cope with the occasional challenging swell conditions encountered at local piers".
Eyewitnesses have suggested that the swimmers had got caught up in a dangerous riptide leading to the fatal incident.
Bournemouth, Christchurch and Poole Council leader Councillor Vicky Slade has said she will be discussing safety at the pier with local MP Conor Burns on Friday.
The local authority's website states that all passenger-carrying boats must be issued with a licence to operate in the area.
It also states from April to October, yellow marker buoys are set out 200 metres from the low water mark to indicate that watercraft must not "go beyond 6 knots, annoy or endanger other beach users or run ashore or launch from the beach."
The nearby Boscombe artificial reef has the speed limit all-year round.
Cllr Slade said: "There is no evidence to suggest any of those rules have been breached.
"We are confident with our partners that any lessons that need to be learned in the future will be learned."
Dorset Police has said they are working with the Marine Accident Investigation Branch and the Maritime and Coastguard Agency to investigate the incident.
