Deck Pumps and Bilge Waters

In days gone by, when European sailing ships were constructed entirely of wooden planks, sailors lived in constant fear of the everpresent leaks through the hull and into the bilge waters below decks. Often the bilge would also double as a latrine, especially on the larger ships with many sailors and just the one ‘head’. It has been said that the bilge water’s stench was also the welcome perfume of a healthy hull, as any freshness would indicate fresh sea water and a potential leak!

In storms, large waves and fierce rains would add to the water level down below, with the lives of all aboard finely balanced against Archimedes’ principle concerning the force of buoyancy. With this in mind, one of the most neglected yet essential pieces of equipment guaranteeing the very last hope for any sailor’s survival at sea, beyond lost rigging or a broken rudder, is the humble bilge pump.

Up until the industrial revolution and the advent of machined metal ‘patent’ pumps in the mid to late 1800s, there were three basic types of bilge pump, the origins of which are ancient and were used in European sailing ships from the 1400s on. These were the Burr Pump, usually a spike with leather burr that drew water up a pipe fashioned from wood. This form of pump is still in common use today for small boats, dinghies and canoes. The chain pump used a chain loop on sprockets with buckets attached to collect water. This form of pump was used in ancient China, Babylonia and later in Roman barges but was generally only fitted to European naval vessels from 1700 to the early 1800s.

The last and most common type of bilge pump was the suction pump that used a handle to drive one or more cylinders, often in brass or bronze housings, with valves that were commonly made from lignum vitae hardwoods. Many ingenious versions of suction or force pumps are known from ancient Greek and Roman times, and modern versions using synthetics and marine grade metals are still in common use today. An innovation on the suction pump was the introduction of the iconic, manually driven flywheels on the decks of larger ships that kept the pumping momentum going.

These ancient forms of bilge pump were superseded in the late 1800s by a revolution in pump design driven by the industrialisation of metallurgy and machining. Called ‘patent’ pumps due to the explosion in design patents, these were all-metal, manual or motorised pumps with a multitude of innovative variations on pump design. One such variation is the cast iron Edson diaphragm deck pump patented by the US Edson Company in 1880 and in common use from 1890 to the 1920s on American fishing schooners.

The Museum’s deck pump pictured, appears to be a copy of a D2 size Edson pump from that era. A 1050 mm handle would have fitted the pump’s socket and been used to manually work the internal diaphragm that would suction and pump bilge water through two chambers. A similar D2 Edson copy, branded ‘Ajax’, is fitted to the Maritime Museum of Tasmania’s ketch May Queen in Hobart.

Manual deck pumps such as the Edson were mainly in use on smaller wooden hulled vessels up to 200 or 300 tons, with many larger sail ships still using flywheel suction pumps. The later motorised ketches and schooners in Australian and New Zealand waters also used these diaphragm pumps as their auxiliary engines were not usually fitted with bilge pumps, while steamships used bilge pumps connected to their engine rooms. After WW2, however, cast iron manual bilge pumps such as the Edson were superseded by the modern motorised bilge pumps in common use today. Nonetheless, Edson still manufactures a modernised version of their old diaphragm pump should you need a manual backup for your yachting adventures!

Many thanks to Ian Scales for identifying the Museum’s pump and providing text for this article.

See also Ship’s Bilge Pumps: A History of their Development 1500-1900 by Thomas J. Oertling.