The 139 is a quantum leap above the Whirlwind in both carrying and all weather ability
Very true Hummingfrog, but is it a quantum leap over a S-61/Sea King that it is replacing? I don't think so. The larger cabin size has had its advantages in many SAR operation even if only a single stretcher case. There is space for the winchman/doctor/medic to work on the casualty. While the AB139 may have nice toys for the pilots, it does nothing for the guys who have to work in the cabin. They will have to move from a spacious working place to a very cramped one. I believe the 412 crewmen in Cyprus are already having complaints about bad backs and knees due to the cramped conditions they have to work in.
Couple that with twin hoists, a FLIR (and console in an already small cabin area) and possibly a skyshout system, plus the SAR medical and winching kits which are of necessity these days especially with the medical qualifications crewmen have (more so than in your Whirlwind days), then the ZFM of the aircraft will be high. What will that leave as disposable load?
Perhaps we will be back to Whirlwind lifting capabilities at Whirlwind Radius of Action (what was it 90nm and a capability of lifting about 3-4 people at that range? - never flew it so only guessing).