That PanAm was a Boeing Stratocruiser from HNL to SFO, and it had a very successful ditch in the Pacific. In fact there are pictures of it available if you search hard enough. It was in contact with a Navy ship which stayed with it all night until it ditched in the early morning light. The main thing learned was that the tail broke off and wrecked the aft cabin. Thus, all in the forward section were safe and secure. Contrary to common sense which dictates TAIL IS SAFEST.
Also to N863DA -
Nice reasearch work! Right-on!
However, about the ONA DC-9. It wasn't the swell, but the fact that the foward bulkhead just aft of L-1 collapsed forward which blocked the main EXIT for that A/C type AND the over-head LIFT RAFT fell out into the aisle and inflated!! What a mess.
The role that the swell played was significant in that the crew instructed the passengers to wait for 3 impacts (or bounces) as they ditched, each one more intense than the last. HOWEVER, the plane went right into a swell, had only 1 major impact and should have been immedeately evacuated. But, the passengers, and cabin crew, were waiting for 2 more bouces!
PS- I worked for ONA and this was reviewed in training. We even had pictures of the passengers in the life jackets in the cabin waiting to ditch!