Big Kev, considering all the technology, dye penetrates and the like LAME's invoke to check out a prop,
seeing a crack with the naked eye means that prop is well and truely past its use by date.
I don't believe any mature pilot needs to ask such a question either. Call it duty of care, self preservation, professionalism, airmanship or anything else you like, none of my pilot associates would operate an aircraft as you hypothetically describe.
Again, if you really need to ask the question, you should not be flying yet as PIC.
tipsy
