Trailing suction hopper dredger

Last updated
DCI Dredge XV (ship, 1999) (IMO 9164122) at Visakhapatnam, India Beach replenishment 04.jpg
DCI Dredge XV (ship, 1999) (IMO 9164122) at Visakhapatnam, India
The dredge drag head of a suction dredge barge on the Vistula River, Warsaw, Poland Poglebiarka ,,Sawa", glowica, Wisla, Saska Kepa, Warszawa 3.jpg
The dredge drag head of a suction dredge barge on the Vistula River, Warsaw, Poland
Trailing suction hopper dredger in action in 1987, Beaufort Sea near Tuktoyaktuk 1987 sucker-dredger Beaufort Sea.jpg
Trailing suction hopper dredger in action in 1987, Beaufort Sea near Tuktoyaktuk

A trailing suction hopper dredger [1] (TSHD) is a type of ship capable of maintaining navigable waterways, deepening the maritime canals that are threatened to become silted, constructing new land elsewhere or replacing sand eroded by storms or wave action on the beaches. This is made possible by large, powerful pumps and engines able to suck sand, clay, silt and gravel. [2]

Contents

Operation

Properties

A trailing suction hopper dredger is self-loading/unloading and sometimes equipped with a pressurized discharging system.

Loading

From the side of the ship one or two suction pipes descend to the bottom of the seabed. On the end of the pipe a so-called trailing drag head is connected. This head is comparable to a large vacuum cleaner and is trailed along the seabed. In the head there are nozzles connected to a high pressure water installation that are capable of loosening the material on the seabed. Due to lower pressure in the pipe, the material will be sucked inward and discharged in the hopper.

The vessel should always have a positive speed over the ground. It is possible to regulate the density of the sucked substance. If the head is lowered, more material will be sucked but this risks damaging the installation because the material can get stuck inside the pipes. Once the mixture is loaded inside the hopper, the substance will sink and the water is discharged overboard, saving on storage space. A trailing suction hopper dredger can only suck relatively loose substance because the steel teeth are not so big. Harder substances such as rock or ironbased rock must be destroyed by a cutter.

Discharging

MV Sand Heron with the hopper visible MV sand heron.JPG
MV Sand Heron with the hopper visible

There are several ways to discharge a TSHD. The most common way is dumping the material.

Equipment

A trailing suction hopper dredger is equipped with the following equipment:

Functions

A dredging vessel [3] and particularly a TSHD is mostly used for

References

  1. "Trailing Suction Hopper Dredger" . Retrieved 22 September 2014.
  2. "Trailing suction hopper dredger" . Retrieved 22 September 2014.
  3. Neha Singh. "Different Types of Dredgers Used in the Maritime Industry". Marine Insight. Retrieved 22 September 2014.