On the Sea King Mk3/3A there were officially 19 passenger seats as far as I can remember. However, practically, far fewer due to equipment, weight, C of G, temperature/performance, fuel, weather etc. A Wessex had far fewer seats but not sure what the official line was, probably two men and a dog with a small bag.
When push came the shove you just crammed people in. Most I had in the back of a Sea King was 24 but the majority of them were children.
