If you have the serial number, you can look up the approximate date of manufacture for Sensenich wooden propellers and carbon composite. Look here to see when your wood prop or carbon blades were made! If you have the serial number, you can look up the approximate date of manufacture for Sensenich wooden propellers and carbon composite. Sensenich props are stamped with a number known as a drawing or design number. The logic of the drawing number sequence is the first number is the length in inches, the middle letters designate the engine and the final digits are the pitch. For example, a 72CK-44 is a 72 inch prop for a Continental engine and has a pitch of 44 inches.