The owner of a boat hire company has said the day cruiser which overturned killing one of ten passengers on board had a 100% safety record.
The upturned hull of the capsized boat
Two sisters, each with their husbands and three children, had hired the boat from Barnes Brinkcraft at Wroxham in Norfolk.
While on the River Bure at Horning, the boat hit a bank and overturned, trapping the two sisters inside an air pocket for an hour on Saturday
The 49-year-old woman from Suffolk tried to resuscitate her 42-year-old sister from Middlesex before they were cut free.
The sisters were airlifted to the Norfolk and Norwich Hospital, where the younger woman died.
Matthew Thwaites of Barnes Brinkcraft said he could not understand how the accident had happened.
Matthew Thwaites could not understand how the boat overturned
"We've run this type of boat with this particular hull shape for seven years with an absolutely 100% record.
"The same type of boat has been running on the Broads for 40 years - again with a 100% record.
"I've never, ever known this sort of thing happening before."
Barnes Brinkcraft have about 100 of the 10-seater day cruisers, which can reach a top speed of 6mph.
Police and the marine accident investigation team are trying to establish the cause of the accident and are appealing for witnesses to come forward.