What was the job of ships boy?

google found a book... "All You Wanted to Know about 18th Century Royal Navy" google.co.uk/books?id=_sKZ3rZK4dQC&pg=PA35&lpg=PA35&dq=%22ships+boy%22+%22age+8%22&source=web&ots=3ntb-OMxpk&sig=HqrZXminamrflCy1DGTXByPTNp0&hl=en">http://books.google.co.uk/books?id=_sKZ3rZK4dQC&pg=PA35&lpg=PA35&dq=%22ships+boy%22+%22age+8%22&source=web&ots=3ntb-OMxpk&sig=HqrZXminamrflCy1DGTXByPTNp0&hl=en

With the following quotes which give some references... "William Bligh of HMAV Bounty fame, went to sea at age 8, listed on the roster of the HMS Monmouth as a ships boy and Captain's servant"

"The ships' boy or a young midshipman would use a half hour glass and each time the sand ran out, he would turn the glass and ring the appropriate number of bells"