Cape Ann granite weighs 168 pounds per cubic foot. Moving stone from the floor of the quarry to the surface posed a major challenge to 19th-century technology. Borrowing techniques that were used on large sailing ships, quarrymen devised an arrangement of blocks-and- tackles and pulleys called a derrick to hoist the heavy stones. Each derrick had a tall vertical post called a mast, and a horizontal arm called a boom. Before steam engines became available in the 1860s, derricks were powered by hand or by teams of oxen. Steam engines made it possible to hoist and move larger blocks of granite from the quarry floor. The granite blocks in front of you supported a donkey engine which rotated the mast and boom of a nearby derrick.
During the quarry’s busiest years, circa 1910, there were four derricks in use here. One had a 96-foot mast and an 80-foot boom. It could lift 40 tons. In 1912, an even bigger one capable of moving larger blocks was erected with a mast that towered 107 feet.
definition from the:
Halibut Point State Park, Massachusetts Department of Conservation and Recreation brochure – 1999
Babson Farm Quarry Self-guided Walking Tour