Balancing a Ship Propeller. “The correct pitch of a propeller is vital for the comfort of passengers on prestigious cruise ships. The prospect of having one’s cocktail continuously shaken is enough for some to cancel the trip. I am sure little thought is given to the man seen in the photograph, who through years of experience makes sure the pitch of the propeller blades is correct, ensuring a fast, economical and vibration-free voyage.” Bull’s Metal and Marine Shipyard, Glasgow, Scotland, 1956