The trailing suction hopper dredger (TSHD) is a versatile vessel that unites dredging, transport and discharge in a single piece of equipment. TSHDs are self-propelled, sea-going vessels with a traditional hull shape. The dredging installation consists of one or two suction arms with dragheads that are lowered off the side of the vessel in order to collect the soil of the seabed. The dredged soil is stored in the dredger’s hold for transport. Hoppers can easily handle soft and loose soils, such as sand, silt and gravel and have a wide range of applications, including the deepening and maintenance of waterways, land reclamation and port construction, mining and the supply of marine aggregates.
Main features of TSHDs:
- hydraulic dredging with one or two dragheads on suction arms and centrifugal pumps
- self-propelled and highly manoeuvrable
- dredges while sailing – making it the dredger of choice for maintenance work, as it does not hinder other marine traffic
- dredged materials transported in the vessel’s well
- suitable for working in open sea, during heavy weather and swell conditions
- discharge via hopper doors, pump ashore facilities or a rainbow installation
- production of up to 24,000m3 per hour while dredging (loading).
How does a TSHD work?
The name trailing suction hopper dredger refers to the fact that this type of vessel dredges while slowly sailing, trailing one or two suction arms off the side of the hull. At the entrance of each suction arm, a draghead is connected. This draghead collects the soil like the mouth of a vacuum cleaner. TSHDs are mainly used to dredge sand, silt and gravel. Compacted sand and coherent soils can also be dredged with special means, such as water jets, blades or rippers in the draghead.
The dredged material is pumped to the hopper, where it is stored for transport. When the hopper is full, the TSHD sets sail to the discharge location. The vessel can empty its hopper in various ways. Depending on the project specifications, the discharge takes place by opening the hopper doors, pumping the material to shore or by ejecting it using a rainbow installation.
The TSHD is a self-propelled, seagoing vessel, and among other advantages, it can be put to work anywhere in the world. Also, it is the only type of vessel that dredges while sailing, making it the dredger of choice for operations in waters where tides and swell occur, and where interference with the movement of shipping cannot be allowed.
Initial investment costs
When opting for a newly-built TSHD, customers can choose a custom-built vessel or a standardised one. Standardised TSHDs are designed, engineered and built as serial products, ensuring fast delivery and excellent quality at a competitive price. These standardized vessels can be customised to individual needs with additional modules, such as extended suction pipes for deeper dredging work, reclamation packages, degassing installations and different types of dragheads. The initial investment cost of a standardised TSHD starts with around EUR 8 million.