I have a person on a B1/B2 visa that wants to work on a forgien flag yacht, does she need to have a TIN if the owner of the yacht is american and he pays out of a US account? Can she apply for a TIN or does this violate her status?

It is likely that an ITIN WILL be required, because the U.S. owner will want to document her salary either by Form w-2 or Form 1099, BOTH of which require a tax ID number.

However, persons with an ITIN are NOT permitted to work, so the B1/B2 visa holder will need to request a Social Security Number (SSN).