There are several architectural options when it comes to building a windmill. One type is a post mill, where the entire mill turns on a post. At the Godfrey Mill, only the top rotates. It is a smock mill, so named because its wooden tower is sloping along eight sides so it looks like a countryman’s linen smock. This was a new style of a tower mill in the 17th century and is the type most seen in New England. The Godfrey Mill is correctly identified as a wind powered grist mill and its purpose was to serve the needs of a growing farming community in Chatham that supplied corn to the mill.

The octagonal mill stands 30 feet tall with a 22-foot diameter, tapering slightly at the top. It has three stories and is taller than most windmills on Cape Cod. Therefore, Godfrey’s Mill was a popular navigation point on the coast for sailors. Its second floor was used for grinding corn, and a unique corn-cob grinder was located on the ground floor. Corn cobs were put into the cob breaker and the shredded cobs were added to animal feed as roughage. On Cape Cod, the cob breaker was also used to grind up large chunks of salt from local salt works in order to bag and ship it.

The mill has two doors opposite each other, so one could enter or exit while the blades were turning, as they took advantage of the wind when it blew from different directions.

The mill is made from large oak beams, with a pine floor and sheathing, and cedar shingles. Originally, its large shaft and gears were both made of wood, but around 1850 an iron gear replaced the wooden wallower.

The top of the mill has a Norfolk cap. This rests on a ring and is an aerodynamic cap shaped like the bottom of a boat turned upside-down, with sides that are broad and taper at the ends.

The tail pole is a spar projecting from the cap of the mill to the ground. It is used to rotate the cap and blades of the mill to turn them into the wind to operate the mill. The length of the tail pole is 37 feet. There is a wagon wheel attached to the bottom of the tail pole, which is used to rotate the mill cap and may have been turned using either a horse, donkey, or one or two men.

The sails originally were made from flax that was grown and woven locally, before cotton sailcloth came into use. These sails covered the arms of the mill that were 8 feet wide and 25 feet long. North-west was the best direction for sails to be set for the most efficient use of the wind. The mill could not operate in winds of less than 10 knots and generally needed wind speeds of at least 20 knots to do the job. But if wind increased to over 25 knots, the miller would have to “reef” the sails to slow them down or stop grinding for the day to prevent damage to the mill’s machinery.

The millstones were cut with deep or shallow grooves or furrows. These patterns in the millstones wore out quickly and had to be re-cut periodically, every 30-35 working days. This work was called “dressing the stones”.