California Supreme Court handed down a rather disturbing ruling recently. This case was on land, involving an auto accident. The net of all of it is that the Good Samaritan exemption is for MEDICAL CARE, not rescuing someone. The looser in this case dragged a person from a car she thought was on fire and in so doing injured the person. She lost the lawsuit because she was not ADMINISTERING MEDICAL CARE.
At sea, the laws are different but if you are coastal boating, within 3 miles, this may very well apply to you if you render assistance. If you pull someone out of the water, this could apply to you. Other states sharks can reference what happened in California.
Here is the court summary:
http://www.courtinfo.ca.gov/opinions...ts/S152360.PDF