Why stationary boiler performance does not transfer directly to ships

Rolling and pitching create movement in boiler water that the design must accommodate. Unsuitable machinery is said to suffer damage and lose pressure or power under those conditions. A stationary plant offers a stable platform, more space and specialist crews working in shifts. It can also favour steady operation near its efficient condition, while a ship must vary firing, pressure and gearing to adjust speed and economy. Additional machinery occupies valuable hull volume and introduces more potential failure points. These differences explain why stationary, railway and marine steam systems cannot be compared through their pressure figures alone.