The Herc can drop as many ASRA kits as you can fit in the freight bay. The radar is pretty good at picking up surface contacts (to the trained eye) and has the capability to handle multiple comms including Marine and Satcom and has homing capabilities. Its also got the range and endurance (incl AAR) to provide on scene cover & comms for a good length of time.
Notwithstanding the fact that we'd all rather stick pins in our eyes than do SAR standby, the Herc is more than capable enough to do the task albeit obviously not as well as a dedicated kipperesque maritime asset. If you don't have one of those then it's the next best thing in our otherwise empty "golf bag".
Have we got the aircraft? Perhaps - it sounds like a job for the Mk3 slicks of 70 Sqn if you ask me. Form an orderly queue fellas! I'd reckon BP would be the man for the job!