SS Otaki was a New Zealand Shipping Company refrigerated cargo steamship that was built in Scotland in 1908 and sunk by a German merchant raider in 1917.

The fuel efficiency and performance of marine steam engines had been improved by compounding in the 1860s, followed by triple and quadruple expansion in the 1880s.

A turbine is smaller, simpler, lighter, faster, smoother and more reliable than an equivalent triple- or quadruple-expansion piston engine.

Otaki was able to go astern efficiently by shutting down her low-pressure turbine, reversing her reciprocating engines and redirecting their exhaust steam straight to her condensers.

[5] Harland and Wolff had built Laurentic's sister ship Megantic with twin quadruple-expansion engines and without a low-pressure turbine,[6] which allowed direct comparison of the two systems.

This led Harland and Wolff to combine reciprocating and turbine power in the much larger RMS Olympic, Titanic and Britannic for White Star Line.

[7] Other shipbuilders adopted the same combination in ships that were large enough to justify having at least three propellers, and that needed a speed of at least 12 to 15 knots (22 to 28 km/h).

However, most merchant ships have only one or two propellers, and in the early decades of the 20th century many ran at an economical speed of 10 knots (19 km/h) or less.

Parsons predicted that a combination of reciprocating and turbine power would eventually be applied to 10-knot ships in the tramp trade,[3] but in practice this was not achieved until the 1920s.

[10] Otaki had five single-ended Howden boilers supplying steam to the pair of three-cylinder triple-expansion engines that drove her wing shafts.

[2] Nevertheless, the combined power of her reciprocating engines and turbine gave Otaki a top speed of 15.7 knots (29.1 km/h; 18.1 mph) on her sea trial,[11] which was faster than most cargo ships of her era.

Late on the afternoon of 10 March the Imperial German Navy raider Möwe intercepted her in the Atlantic about 420 miles west of Lisbon.

However, as a refrigerated ship built to carry food, Otaki was highly valuable to the Allied war effort.

[16][17] Otaki's gunners were accurate, hitting Möwe''s superstructure and hull, setting fire to coal in her bunkers, killing five German crew and wounding 10 others.

The youngest was a 14-year-old midshipman, William Esson Martin, who had joined the ship in England only weeks before she was sunk.

On her way home she sank two more merchant ships, but the damage inflicted by Otaki had forced the end of Möwe's raiding career.

[19] The school annually awards the Otaki Shield,[23] presented by Smith's family, to a boy who is "pre-eminent in character, in leadership and in athletics" and P&O, which absorbed the NZ Shipping Co in 1973, pays for the winner to visit New Zealand.