Logging sea time on dive charter vessels

As a dive instructor or divemaster working as a deckhand on charter vessels, I wonder why the skipper must be certified, the dive instructor certified, the divemaster certified, the divers certified or at least under direct instruction of a certified instructor, yet the deckhand doesn't require certification.

The greatest ability of the working divemaster/deckhand is to log seatime for future commercial qualifications whilst gaining valuable experience. Now, such qualifications differ from region to region, likewise, logging sea-time on lakes and sheltered waters is enormously different from sea-time under adverse conditions but it is a start.

Using untrained and inexperienced staff has been the norm with informal training sometimes leading to experienced staff. I would prefer traineeships where an unqualified deckhand works under the direct supervision of the skipper. This is pretty much what happens now to a certain degree with the exception of the deckhand being qualified, the industry has resisted qualifications for deckhands and this industry norm should be reconsidered.