This will depend upon a few variables. When you say "Rescue" are you in Distress
? or just in need of "Urgent" assistance? The difference being that Distress
means that "There is a Person, Vessel Aircraft of Vehicle in grave and imminent danger
and in need of Immediate assistance" and Urgent does not require "Immediate Assistance". Most maritime nations around the world will call out to a genuine Distress call free of charge. However there are good number of nations that will charge for an Urgent call out.
It is possible that your vessel insurance
company will pickup the cost of recovery, check the small print in your policy.
I always insist that crew have travel insurance and that it covers medical
assistance and re-patriation. You will find that most sea schools and charter
companies recommend this.
Here in the UK the RNLI will always come out free of charge, just across the English Channel
the majority of Life Boat are privately owned and do have the ability to charge.