Propeller pattern for tugboat ALERT

propeller pattern

Wooden shipbuilding pattern for 3 blade propeller for tugboat. Single blade with half diameter at center, painted black. Marked on blade in yellow paint: "27568/ TUG ALERT/ DIA. 6'-5"/ Pitch 4'-5"/ 3 Blades". ALERT (steam tug, bu. 1913, owned by T.A. Scott Co., built by New London Marine Iron Works, 99 gr. tons, 89.9 x 19.9.) Diameter of base 14-1/2".