As the Bv234 was almost as wide as it was long and had the stability of a barge the implications of a ditching were that it would be almost impossible to overturn, thus it did not even need floatation gear.
It is indeed curious how contrary people can be on this forum against the presented evidence
1988 'Flight' archive:
...of a bypass valve.
The report highlights a series of shortcomings in the operation and maintenance of the helicopter. It says that a
number of screws on other actuators were grossly undertorqued and that the operator, British Airways Helicopters, had failed effectively to investigate or resolve similar occurrences before the accident.
A damaged rear cargo ramp seal had allowed water into the ditched helicopter, which capsized about 80min after ditching.
Pre-flight flight control
Luckily the weather was calm at the time so all 47 passengers and crew were rescued. Even more luckily, the aircraft was ditched only 6 miles from Cormorant A so 2 Bristow SAR equipped Bell 212s, Rescue 45 and 46 were on the scene just a short time after. Had the aircraft ditched at night, in bad weather a long way from the Brent complex who knows what might have happened.
The Chinook was a horrible aircraft to be a passenger in. It was uncomfortable and despite the large cabin, the relatively small, high windows made it feel cramped and many of the passengers, who were scared of flying in many helicopters, were even more scared by the Chinook. My bag being ruined by a large hydraulic leak into the baggage compartment was the last straw and afterwards I always flew fixed wing to Sumburgh and then in an S61 rather than the Chinook
