Despite its age, this instructional masterpiece is filled with a wealth of mechanical knowledge. The music that plays in this training video evokes a feeling similar to that of being in a shop class in the 1970s. The size of these engines is also astonishing when you see them up close.
Via YouTube: Most modern ships use a reciprocating diesel engine as their prime mover, due to their operating simplicity, robustness, and fuel economy compared to most other prime mover mechanisms. The rotating crankshaft can be directly coupled to the propeller with slow-speed engines, via a reduction gearbox for medium and high speed engines, or via an alternator and electric motor in diesel-electric vessels. The rotation of the crankshaft is connected to the camshaft or a hydraulic pump on an intelligent diesel.
The reciprocating marine diesel engine first came into use in 1903 when the diesel-electric river-tanker Vandal was put into service by Branobel. Diesel engines soon offered greater efficiency than the steam turbine, but for many years had an inferior power-to-space ratio. The advent of turbocharging however hastened their adoption, by permitting greater power densities. Diesel engines today are broadly classified according to
Their operating cycle: two-stroke engine or four-stroke engine
Their construction: crosshead, trunk, or opposed piston
Their speed
Slow speed: any engine with a maximum operating speed up to 300 revolutions per minute (rpm), although most large two-stroke slow speed diesel engines operate below 120 rpm. Some very long stroke engines have a maximum speed of around 80 rpm. The largest, most powerful engines in the world are slow speed, two stroke, crosshead diesels.
Medium speed: any engine with a maximum operating speed in the range 300-900 rpm. Many modern four-stroke medium speed diesel engines have a maximum operating speed of around 500 rpm.
High speed: any engine with a maximum operating speed above 900 rpm. Most modern larger merchant ships use either slow speed, two stroke, crosshead engines, or medium speed, four stroke, trunk engines. Some smaller vessels may use high speed diesel engines.
The size of the different types of engines is an important factor in selecting what will be installed in a new ship. Slow speed two-stroke engines are much taller, but the footprint required is smaller than that needed for equivalently rated four-stroke medium speed diesel engines. As space above the waterline is at a premium in passenger ships and ferries (especially ones with a car deck), these ships tend to use multiple medium speed engines resulting in a longer, lower engine room than that needed for two-stroke diesel engines. Multiple engine installations also give redundancy in the event of mechanical failure of one or more engines, and the potential for greater efficiency over a wider range of operating conditions.
As modern ships’ propellers are at their most efficient at the operating speed of most slow speed diesel engines, ships with these engines do not generally need gearboxes. Usually such propulsion systems consist of either one or two propeller shafts each with its own direct drive engine. Ships propelled by medium or high speed diesel engines may have one or two (sometimes more) propellers, commonly with one or more engines driving each propeller shaft through a gearbox. Where more than one engine is geared to a single shaft, each engine will most likely drive through a clutch, allowing engines not being used to be disconnected from the gearbox while others keep running. This arrangement lets maintenance be carried out while under way, even far from port.
The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient engine in the world today.It comes in 6 cylinder in-line through to a whopping 14 cylinder version. The cylinder bore is 38 inches and the stroke is just over 98 inches. Each cylinder displaces 111,143 cubic inches (1820 litres) and produces 7780 horsepower. Total displacement comes out to 1,556,002 cubic inches (25,480 litres) for the 14-cylinder version.The RTA96C-14 can achieve a maximum power output of 108,920 hp at 102 rpm. At a length of 89 feet and a height of 44 feet, the total engine weight is 2300 tons – the crankshaft alone weighs 300 tons.