Grimsby's other dock tower

One cannot visit the former important fishing port of Grimsby, in Lincolnshire,  England without at least catching sight of it's most iconic structure, the dock tower. The prominent Grimsby Dock Tower is a hydraulic accumulator tower which  was used to provide hydraulic pressure  to power the machinery (cranes, lock gates and sluices) of the Grimsby Docks. The  extreme height of the tower (200 feet) was necessary, at the time, to achieve sufficient pressure. However there is another, less prominent, accumulator tower on the opposite side of the dock. It is dwarfed by it's more famous companion  and yet it represents a major step improvement in hydraulic technology and should not be ignored.

The tall, and more famous, tower is one of William Armstrong's earliest applications of hydraulic power, and is believed to be the only hydraulics system of its type to be built. It is important as a representative of the first stage of hydraulic-power technology which operated on relatively low pressure, with the pressure being gained through height, from an elevated water tank. 

Almost as soon as the tower was built its design was seen as out of date because of the invention, by Armstrong, of the weighted accumulator. Weighted accumulators can be less tall (and can achieve higher pressure) because the column of water is pressurised by lifting a piston loaded with a heavy weight ( in this case 300 tons). This makes much less demands on foundations. The  taller Dock Tower continued to provide water for hydraulic working until 1892 when the erection of the weighted hydraulic accumulator tower, only 78 feet high,  on the opposite pier approximately 200 feet  to the North West took over the role.  This smaller tower is often overlooked by visitors.

Present dock and lock machinery are powered by electric or electro-hydraulic energy and thus both accumulator towers are redundant but important reminders of previous approaches to  high power mechanisms.