Since being a seaplane precluded the possibility of the pilot swinging the propeller by hand in order to start the engine, a crank was provided inside the cockpit that wound a spring that could be used to turn the engine over.
In seaplanes, the pilot's ability to manually turn the propeller was limited due to its design. To overcome this, a hand-crank within the cockpit was incorporated, which wound a spring to start the engine.