Pump

Apr. 29, 2024

Pump

An essential piece of mechanism on board ship, used for emptying the bilges of any water which may have collected in them. Three types of pumps were fitted in the old sailing vessels to clear the bilges. A small hand-pump, similar to those used ashore, was placed near the mainmast, used when there was only very little water in the bilge and a short spell of pumping would clear it. It was a slow and laborious method. Some ships, particularly Dutch and German ones, used a burr-pump, also known as a bilge pump, in which a spar of wood about 1.8 metres (6 ft) long had a burred end to which a leather was fixed. Two men standing over the pump thrust this down into the box in which the bilge water collected, and six men then hauled it up by a rope fixed to it, thus lifting the water which lay on top of the leather. The third type was the chain-pump, which worked on a similar system to the burr-pump but with an endless motion so that there was no need for men to thrust it down in the bilge-box on each stroke. This was a most efficient pump, and two men working on it could lift a ton of water in 55 seconds. According to Sir Walter Raleigh, it was one of the improvements—bonnets, studsails, anchor capstans, and the ability to strike down a ship's topmast being the others—introduced into the British Navy during his time.

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Modern pumps in ships are power driven and are capable of lifting some hundreds of tonnes of water an hour. Most smaller yachts have hand-operated diaphragm pumps which are more efficient than the plunger type. In steamships and their modern equivalents there are many other types of pump, used in connection with their internal machinery, such as fuel pumps to feed the boilers, circulating pumps to draw in seawater for the condensers, feed pumps to return condensed steam to the boilers, trimming pumps to transfer water ballast from one tank to another, and so on.

15th Century Pump | The Engines of Our Ingenuity

Today, we speak of bilge water and exploration. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

What was the most important supply item on board a sailing ship? Was it canvas? Spare masts? Food? Water? Texas marine historian Thomas Oertling flatly states that a compact, efficient pump was most important of all.

Just imagine, if you can, sailing a thousand miles from any shore and finding you have a loose seam below the waterline. Imagine riding a wooden vessel with the ocean seeping in faster than it should. We call that leakage bilge water; and bilge remains a nasty word even today.

After Columbus, voyages stretched into months, and bilge water became terrifying stuff indeed. History books don't say when the suction pump replaced bailing buckets. It was invented 60 years before Columbus, but as a laboratory curiosity. Miners put it to work on a different kind of bilge a generation after Columbus. They found they could drive their shafts deeper into the earth once they could get rid of the water that seeped in.

Those first suction pumps were pretty simple -- long tubes with plungers down the middle. You pulled the plunger and it sucked water up from below -- like a hypodermic needle in reverse. The plunger had a leather flap valve. It let water through when you pushed it down, but the flap sealed it tight when you lifted it up. A laborer pushed the plunger up and down, and water flowed steadily upward.

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But in 1982 we finally found a shipboard pump that predated those mining pumps. Marine archaeologists dove into a wreck off Molasses Reef in the British West Indies. They found a four-inch lead plunger with valve holes in it. It was part of a suction pump installed right after Columbus's first voyage.

This mute remnant tells a story about technology and the world around it -- a story you can't find in written records. The suction pump had little purpose when the world began opening up to exploration. Intellectual play, not necessity, drove its invention. Now, all at once, miners and shipbuilders alike pressed it into the service of an expanding world.

The simple suction pump was a subtle machine. It's far easier to understand it than it ever was to invent it. We're reminded of the nursery rhyme of the kingdom and the horseshoe nail. The kingdoms of the Western Hemisphere and of the subterranean world both depended on the suction pump. This small voyage of somebody's inventive mind made far grander voyages possible.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

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Oertling, T.J., A Suction Pump from an Early 16th-Century Shipwreck. Technology and Culture, Vol.30, No. 3, 1989.

From the 1832 Edinburgh Encyclopaedia

Construction of a simple flap valve

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