Description by Robert "Beast" Isenberg
The master carpenter is in charge of all structures onboard ship (i.e. the hull, masts, yard arms, rudder, ship's boats and such). Generally there are a few mates, joiners & coopers under his charge. The master carpenter answers to the bosun, informing him of what maintenance/damage control/fabrication/purchases need to be done.
This part of the crew needs light to do their job, so they do not pull a watch; they work from dawn to dusk. They are called idlers. This does not mean they stop working at night if the ship is badly damaged or endangered from the elements.