Steam Engine: Cylinder Head

You are standing next to the cylinder heads of the ship’s main engine; a three-cylinder, triple-expansion, double-acting steam engine designed before the turn of the 19th century by Scottish and English engineers. It is driven by steam generated in the two boilers. The controls for the engine and other machinery are located below, but critical valves are also linked to control wheels on the main deck. This allowed wartime crew to shut off the boiler fires and stop the main engine if the ship was torpedoed and the engine room crew became incapacitated. The engine is a closed, freshwater system, powered by steam superheated to four hundred and fifty degrees Fahrenheit so this area is very hot, sometimes exceeding one hundred and thirty degrees Fahrenheit.

Boilers heat the water to create high-pressure steam. Steam is first introduced at its highest pressure to the smallest cylinder. It expands into a larger, middle cylinder so as the pressure drops it maintains the same amount of thrust on the piston and push rods and below. This process is repeated with the steam going into the third, largest cylinder. From there, the low-pressure waste steam is sent to the condenser where it is turned back into water and filtered of oil and rust. It is then pumped back to the boilers to recreate steam and repeat the cycle.

The engine turns the single eighteen-and-a-half-foot diameter propeller at seventy-six revolutions per minute producing a top speed of eleven knots, or just under thirteen miles per hour. Though the engine only produces two thousand five hundred horsepower, it surprisingly develops one hundred and seventy-six thousand foot-pounds of torque, or the twisting force needed to turn the propeller, commonly called the ship’s screw.

CAUTION: Be aware that all this machinery is fully operational. Please do not turn valves, throw switches, or touch any of the equipment. Use both hands on the rails when descending to the lower levels.

THIS IS A SAMPLE OF AN EMBEDDED SLIDER SLIDESHOW