Fugazi1000, you need to find a copy of the film The Sea Shall No Have Them which was a story of the RAF Air-Sea Rescue. It has been on the TV fairly recently and is quite a good film. 1955.
Even with SAR helicopters, the launches were still a vital part of SAR in the 60s as the Whirlwind was, I was told, unable to rescue a V-bomber crew if it was more than 10 miles off-shore. In those days we all had SARAH and were briefed to work out when the SAR might reach us and then switch on the SARAH to conserve its battery. If there were 2 or more of us then only one SARAH would be switched on, may be 2 if there were 5 of us. Passengers were not issued with SARAH life-jackets.
If we had gone down in the North Sea we might wait a couple of hours of more before we thought a Shackleton could reach the area and also switch off at night unless we could hear a search aircraft. With an 8 hour battery life we would depend on the ASR Launches more than the Whirlwind.