Engineering Schemes

Introduction a century of diesel progress

Ninety years after the entry into service of Selandia, generally regarded as the world's first oceangoing motor vessel, the diesel engine enjoys almost total dominance in merchant ship propulsion markets. Mainstream sectors have long been surrendered by the steam turbine, ousted by low and medium speed engines from large containerships, bulk carriers, VLCCs and cruise liners. Even steam's last remaining bastion in the newbuilding lists—the LNG carrier—has now been breached by competitive new dual-fuel diesel engine designs arranged to burn the cargo boil-off gas.

The remorseless rise of the diesel engine at the expense of steam reciprocating and turbine installations was symbolized in 1987 by the steam-to-diesel conversion of Cunard's prestigious cruise liner Queen Elizabeth 2. Her turbine and boiler rooms were ignominiously gutted to allow the installation of a 95 600 kW diesel-electric plant.

The revitalized QE2's propulsion plant was based on nine 9-cylinder L58/64 medium speed four-stroke engines from MAN B&W Diesel which provided a link with the pioneering Selandia: the 1912-built twin-screw 7400 dwt cargo/passenger ship was powered by two Burmeister & Wain eight-cylinder four-stroke engines (530 mm bore/ 730 mm stroke), each developing 920 kW at 140 rev/min. An important feature was the effective and reliable direct-reversing system.

Progress in raising specific output over the intervening 70 years was underlined by the 580 mm bore/640 mm stroke design specified for the QE2 retrofit: each cylinder has a maximum continuous rating of 1213 kW.

Selandia was built by the Burmeister & Wain yard in Copenhagen for Denmark's East Asiatic Company and, after trials in February 1912, successfully completed a 20 000 mile round voyage between the Danish capital and the Far East. The significance of the propulsion plant was well appreciated at the time. On her first arrival in London the ship was inspected by Sir Winston Churchill, then First Lord of the Admiralty; and Fiona, a sistership delivered four months later by the same yard, so impressed the German Emperor that it was immediately arranged for the Hamburg Amerika Line to buy her.

Figure I.1 One of two Burmeister & Wain DM8150X engines commissioned (1912) to power the first Selandia (MAN B&W Diesel)

A third vessel in the series, Jutlandia, was built by Barclay, Curle in Scotland and handed over to East Asiatic in May 1912. The Danish company's oceangoing motor ship fleet numbered 16 by 1920, the largest being the 13 275 dwt Afrika with twin six-cylinder B&W engines of 740 mm bore/1150 mm stroke developing a combined 3300 kW at 115 rev/min. Early steam-to-diesel conversions included three 4950 dwt vessels built in 1909 and repowered in 1914/15 by the B&W Oil Engine Co of Glasgow, each with a single six-cylinder 676 mm bore/ 1000 mm stroke engine developing 865 kW at 110 rev/min.

Selandia operated successfully for almost 30 years (latterly as Norseman) and maintained throughout a fully loaded service speed of 10.5 knots before being lost off Japan in 1942. The propulsion plant of the second Selandia, which entered service in 1938, demonstrated the advances made in diesel technology since the pioneering installation. The single, double-acting two-stroke five-cylinder engine of the 8300 dwt vessel delivered 5370 kW at 120 rev/ min: three times the output of the twin-engined machinery powering the predecessor.

The performance of Selandia and other early motor ships stimulated East Asiatic to switch completely from steamers, an example followed by more and more owners. In 1914 there were fewer than 300 diesel-powered vessels in service with an aggregate tonnage of 235 000 grt;

Figure I.2 A 20 bhp engine built in 1898 by Burmeister & Wain to drawings supplied by Dr. Diesel, for experimental and demonstration purposes. MAN built the first diesel engine—a 250 mm bore/400 mm stroke design—in 1893

a decade later the fleet had grown to some 2000 ships of almost two million grt; and by 1940 the total tonnage had risen to 18 million grt embracing 8000 motor ships.

Between the two world wars the proportion of oil-engined tonnage in service thus expanded from 1.3 to 25 per cent of the overall oceangoing fleet. By 1939 an estimated 60 per cent of the total tonnage completed in world yards comprised motor ships, compared with only 4 per cent in 1920.

Evolution of large two-stroke engines