Some astute observations above, and not such a far fetched idea.
As was mentioned, seaworthiness is covered in existing regulations. It's part of every owner/master/skipper's General Safety Obligation (read "Duty of Care") to ensure their 'ship' is Safe, Properly Equipped & Crewed and Operated in a Safe Manner. That covers it all really, guess it comes down to interpreting the duty of care obligations.
Ensuring a ship (boat,vessel, etc) is Safe, is ensuring it's seaworthiness. It's the operators responsibility.
Whether or not every operator is capable of determining seaworthiness is perhaps another issue.
regards
Steve