Bilge (water)

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Bilge pump on the Friederike von Papenburg

As Lenzen (lower German lens = "blank") is generally designates the pumping of water from a water vehicle , or in civil engineering .

Watercraft

In watercraft, the water that collects in the lower part of a ship's hull , the bilge , in the event of a leak or during normal operation is pumped .

The ballast water of large cargo ships, which gives them stability when they are empty, is also pumped out. Due to ecological problems caused by organisms introduced into foreign waters, the ballast tanks are usually emptied in deep waters at sea and refilled with water from the open sea until filter measures are introduced.

Bilge pump

Bilge pump of a LuAZ-967 in operation

Often this is a so-called bilge pump , also bilge pump ( bilge ) called for use, which is usually optimized to high volumes to transport water. The safety regulations for pleasure boats stipulate that at least one bilge pump must be a hand pump. If water gets into the hull, there is a significant risk that the batteries that operate the electric pumps will get wet and fail, as they are placed very deep in the hull for practical reasons.

In the meantime, however, vehicles other than ships also have bilge pumps, for example some tanks (such as the Leopard 2 ), which can thus cross bodies of water more safely.

Bilge flap

Bilge flaps or bilge valves are mostly manually operated opening valves , with the help of which smaller sport boats bring water overboard again. The bilge flaps are below the water level ( 420 dinghy , laser ...), here the bilge is only possible with sufficient speed. They work due to the suction effect that arises when driving through the water (principle of a water jet pump ). They do not work if the height difference between the cockpit floor and the water surface is too great. If either the speed is too low or the bilge flap is too low, the water flows back into the boat, if this is not prevented by a check valve .

Paul Elvstrøm , the most successful regatta sailor in Denmark, was the inventor of the self-bailer .

  • Self-bailer

  • Bilge flap

  • Bilge flap

  • Lateral bilge flap of a dyas

  • above: closed, below: open (interior view)

Self-draining cockpit

self-draining cockpit

A self-draining cockpit is used for sailing boats whose cockpit floor is above the surface of the water, so that a simple opening to the outside is sufficient to direct splash water overboard. In modern racing yachts, the entire aft section has been opened so that even large amounts of water, such as those that can penetrate from breakers, can be drained off quickly. On larger yachts (e.g. for ocean races) there is therefore only a closure in the form of a simple railing at the stern to prevent someone from being washed overboard. All of the currently valid CE Seetauglichkeitseinstufung pleasure boats built are over cockpit and cockpits have, "the (are) self-draining or have other means to prevent the penetration of water into the boat interior."

Bilge pipe

On smaller yachts, the cockpit floor is often closed to the rear and sides. Large bilge pipes then connect the bottom with the hull and thus lead the water directly into the sea.

Lenzen by means of Pütz or Ösfass

A pütz can be used for pumping

Technical means for bilge, such as bilge pumps, can fail. For example, the suction opening can become clogged or the power supply fails. For these cases, at least two buckets with a leash on the handle, also known as Pütz or Schlagpütz, should be carried on board. With such a Pütz larger amounts of water can effectively be drawn from a ship.

In special cases, for example on very small dinghies like the youngest sailboat Optimist , the Ösfass , which is also known by sailors, is used.

Civil engineering and mining

In civil engineering , one has to struggle with groundwater, but also rainwater when there is a downpour. If there is little water entering the excavation or the tunnel, the water is continuously pumped out. As in mining , this process is called dewatering .

If the groundwater level is high and excavation pits are deep, sheet piling is knocked down or the excavation is secured with similar measures. Then the earth is dredged to the desired depth below the water level and the excavation is sealed with underwater concrete , which z. B. is to be secured with anchors against the buoyancy caused by buoyancy of the structure in the surrounding groundwater. As an alternative or in addition to anchoring, there are a few other methods, e.g. B. the increase in the load by building with heavy concrete .

If the basement floors are to be built over and the design or project schedule allows it, the floors above can be built as a load even before the basement is drained, in order to prevent the basement from being lifted by the then missing load float up. [Receipt?]

From the point of view of statics, building in the groundwater area is a complex problem, which requires a meticulous procedure in planning, calculation and execution.

swell

  • Dietmar Bartz: Sailor's Language - From Tampen, Pütz and Wanten. Delius Klasing, Bielefeld 2007, ISBN 978-3-768-81933-6 .

Individual evidence

  1. ↑ Recreational craft guidelines with comments (PDF; 1.6 MB), page 40
  2. ↑ https://vzb.baw.de/publikationen/kolloquien/0/04-SchuppenerAufschwimmen%20richtig.pdf - Floating up and hydraulic ground failure - Dr.-Ing. B. Schuppener, Federal Institute for Hydraulic Engineering, Karlsruhe - Page 5: Section 2.3.1; Page 11: Section 1 Paragraph 2
  3. ↑ http://www.heidelbergcement.de/de/system/files_force/assets/document/architekten-folder_05_baustoffe_fuer_spezische_lösungen_2016.pdf - page 26 section 5.13