An RAF helicopter, 20 coastguards and four lifeboats were involved in the operation to reach the four, trapped at the back of a cave being filled with incoming sea water.
The chain of disastrous events began after the father saw his 11-year- old son getting into difficulties as he surfed on the seas at Tintagel, and went into the water himself to help the boy.
As the boy was being carried out to sea by the heavy swell his father swam after him, and they both managed to reach what they thought was the safety of a cave.
However, when the Port Issac lifeboat came to their aid and tried to reverse into the cave, it was tipped over by the rollers crashing into the mouth of the cave - and two lifeboatmen went overboard.
They managed to reach the sand bank at the back where the boy and his father were waiting, but were then themselves also in need of rescue.
As darkness approached an RAF rescue helicopter from Chivenor in north Devon hovered overhead in a joint operation involving coastguards and two larger lifeboats from Boscastle and Padstow.
However, the wreckage of the first lifeboat was blocking the cave entrance. Bude lifeboat also had to turn back as the heavy white water swell made a rescue attempt too dangerous, coastguards said.
Finally, as the tide turned at about 10pm, the two coastguard teams prepared to abseil down the 250ft-high cliff face to the cave entrance while fire brigade crews brought extra lighting.
The trapped party of four people were eventually hoisted by rope up to the cliff top.
The father and son were both suffering from hypothermia, and one had a rib injury and one a shoulder injury. They and the two lifeboatmen were flown to hospital at Barnstaple in Devon.
Another lifeboat crew were hailed as heroes last night after saving four young people and their dog, who had become trapped by the incoming tide on rocks underneath coastal cliffs between Clarach and Wallog, just north of Aberystwyth, in Wales.
The RNLI lifeboat from nearby Borth rescued them as they were about to be swept into the heavy seas.