Ship's pulley

I was given this old pulley a couple of years ago and although it is a very interesting piece of history I have run out of room to properly display it. Note the markings on the face: D Adams Boston Maker. It measures 18 inches high by 15 inches wide with hemp wrapped around the entire pulley extending above 15 inches in double loops. It weights about 45 lbs. I would appreciate any information about this beautiful piece of nautical history and perhaps some idea of the value.