Ships contain simple systems that are easy to operate and easy to understand, which makes them easy to fix, which means they have less downtime. An important quality, considering that “downtime” for a ship could mean being stranded thousands of miles from help.
Take the ship’s steering system, for instance. The rudder is pushed left or right by metal rods. Those rods are moved by hydraulic pressure. That pressure is controlled by a hydraulic pump. That pump is controlled by an electronic signal from the wheelhouse. That signal is controlled by the autopilot. It doesn’t require a rocket scientist or a naval architect to find the cause of and solution to any problem: