You are held to the same standards as in any accident. The common citizen is held blameless for any efforts made at life-saving or first aid while a doctor performing the same acts is held to the standards we expect of physicians.
If you possess a marine license you will quite likely be held to the same standards. As a practical matter, while engaged in recreational boating, you'd be well advised to not bandy the fact about. While it is a matter of public record, you should feel no compunction towards not leading lawyers, law enforcement, or prosecutors into a search of that public record.
And boasun's words are certainly worth heeding.
“Scientists are people who build the Brooklyn Bridge and then buy it.”
Wm. F. Buckley, Jr.