SASless:
The S61 had been in service for many years before it was considered for the SAR role. Most of the procedures, equipment fit and operating data were based on its near cousin, the Sea King. Therefore, the S61 was not an 'out of the box' SAR machine, some thought and experience had gone into the decision.
Nick Lappos:
Everything you say about the 'venerable S61' is true. It is old, the performance is poor and its avionics fit is antiquated. But, as you will see from my reply to SASless - see above - some thought and experience went into its selection. Some operating data has been gathered about the S92, the EH101 and the EC225, the one that really concerns me is the AB139. Reading some of the flight test histories available on the net - admittedly hearsay - there seems to be a few problems with this airframe. Also, is it big enough, can it carry the kit and the personnel?