OH,
Trog is correct, managed to find a picture showing the elongated hole in the strong plate behind the hook on the Seaking hoist at the address below.
The Crewman attaches a HIFR sling to this point and the hard lift point on the hose, then disconnects the hoist from the hose.
The HIFR sling is a manually operated quick release item, should all else fail and the hose won't break away in an emergency.
Sea King Walk Around Photo Index Page
Cheers now