A Hastie-built variable delivery pump of the Hele-Shaw rotary plunger type supplied as a component of the firm's electro-hydraulic steering gear. This type of pump enables the direction of movement of the hydraulic fluid in the steering system to be reversed without reversing the rotational direction of the pump. A similar Hele Shaw pump is preserved at the McLean Museum, Greenock (catalogue No DB210.1)&lt;br /&gt;
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Sources: 'Verbal Notes &amp; Sketches for Marine Engineer Officers' 19th Edition Volume II page L20, J W M Sothern, Sothern's Marine Engineering College, Glasgow.&lt;br /&gt;
'Steering Gears' by G Buchanan from 'The Running &amp; Maintenance of Marine Machinery', (3rd Edition, 1949), The Institute of Marine Engineers, London