Trailing Suction Dredger Mud Door Cylinder

Trailing suction dredger mud door cylinder — the hydraulic actuator that opens and closes the hopper bottom discharge door on trailing suction hopper dredgers. Bore 400 mm, rod 200 mm, stroke 1,400 mm, pull force up to 2,355 KN, 32 MPa. Can be equipped with displacement sensor for automated door control. Korea Ever-Power. ISO 9001. OEM & ODM.
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Trailing Suction Dredger

Trailing Suction Dredger Mud Door Cylinder

The hopper is full. Time to dump. The mud door cylinder pulls open the bottom discharge doors — 2,355 KN of pull force dropping thousands of tonnes of dredged material onto the seabed in a controlled, metered discharge. Then it closes the doors and the dredger goes back to work.

400mmBore
1,400mmStroke
2,355 KNPull Force
32 MPaPressure

Technical Specifications

Parameter Specification
Product Name Trailing Suction Dredger Mud Door Cylinder
Features Pulling force for opening/closing the mud door; optional displacement sensor
Bore Diameter 400 mm
Rod Diameter 200 mm
Stroke 1,400 mm
Pulling Force Maximum 2,355 KN
Working Pressure Up to 32 MPa
Sensor Optional external displacement sensor
Temperature Range -40 °C to +100 °C
Application Trailing Suction Dredger

What Is the Mud Door on a TSHD?

TSHD hopper dredger bottom discharge operation

The mud door is a hinged steel plate (or pair of plates) at the bottom of a trailing suction hopper dredger's hopper. When closed, the mud door seals the hopper floor, allowing the vessel to carry dredged material during transit. When opened, the mud door swings downward and the cargo falls through the opening onto the seabed — a process called bottom dumping or bottom discharge.

The mud door cylinder provides the pull force to open the door against the weight of the cargo pressing down on it, and the push force to close and re-seal it after discharge. On large TSHDs (8,000–30,000 m³ hopper capacity), the cargo weight pressing on the mud door can exceed 15,000 tonnes — distributed across 4–8 mud door cylinders. Each cylinder must contribute its share of the opening force while maintaining synchronised door movement across the full set. Browse the offshore hydraulic cylinder range for related TSHD products.

Bottom Discharge vs Overflow Discharge

TSHDs have two discharge methods. Each uses a different hydraulic cylinder, and the choice depends on the disposal site and environmental requirements:

Bottom Discharge (Mud Door)

The mud door opens and cargo drops through the hull bottom. Fastest discharge method — 5,000 m³ can be dumped in 3–10 minutes. Used when disposal is directly below the vessel (offshore disposal sites, deep-water dumping). The mud door cylinder (#7) provides the opening and closing force.

Overflow Discharge (Overflow Tube)

Excess water overflows through a vertical tube in the hopper, carrying fine sediment with it. Used during loading to increase the solids density in the hopper. The overflow cylinder (#8) raises and lowers the tube to control the overflow height and flow rate.

Displacement Sensor Integration

Trailing Suction Dredger Mud Door Cylinder

The mud door cylinder can be equipped with an external displacement sensor that reports door position to the vessel's automation system in real time. This enables:

  • Precise door opening control — partial opening for controlled, metered discharge instead of full dump. Critical for beach nourishment projects where material must be placed in thin, even layers.
  • Synchronised multi-door operation — on TSHDs with multiple mud doors (typically 2–4 pairs), the sensors ensure all doors open at the same rate, preventing asymmetric loading that could destabilise the vessel.
  • Cycle logging and predictive maintenance — the automation system records every open/close cycle, door travel speed, and cylinder pressure. Deviations from baseline indicate seal wear, hinge friction, or hydraulic flow problems before they cause failures.

Why Choose Korea Ever-Power for TSHD Hydraulic Cylinders

Matched Sets for Multi-Door Systems

All mud door cylinders for a vessel are manufactured from the same material batch, honed on the same setup, and pressure-tested to the same standard — ensuring identical force output and speed across the full set.

Marine-Grade Anti-Corrosion

Ceramic spraying, laser cladding, or hard chrome on the rod surface. FKM seals for saltwater resistance. The mud door cylinder operates in the wettest zone on the vessel — continuous seawater contact during every discharge cycle.

Fast Turnaround

8–12 weeks standard, 5–6 weeks emergency. A failed mud door cylinder prevents discharge — the vessel must return to port with its full cargo. Every hour of delay costs USD 5,000–15,000 in vessel hire alone.

Hydraulic cylinder types and configurations

Frequently Asked Questions

How many mud door cylinders does a typical TSHD use?

Most TSHDs have 2–4 mud doors, each operated by 1–2 cylinders. A large TSHD (15,000+ m³) may have 8 mud door cylinders in total. Korea Ever-Power supplies complete matched sets.

Can the mud door cylinder be fitted with a position sensor?

Yes — an external linear displacement sensor (magnetostrictive or cable-extension type) can be mounted alongside the cylinder. The sensor output integrates with the vessel's PLC or SCADA system for automated door control.

What is the typical discharge time using mud doors?

Bottom discharge through mud doors takes 3–10 minutes for a full hopper, depending on hopper volume, door opening area, and material type. Wet sand flows faster than cohesive clay.

How does the mud door seal after closing?

The mud door has replaceable rubber or polyurethane seals along its edges. The cylinder provides the closing force to compress these seals against the hopper frame. Seal condition is checked during each drydocking.

What classification approvals are available?

BV, DNV, LR, ABS, and CCS documentation and witnessed testing. Contact the Korea Ever-Power offshore hydraulic cylinder team for your vessel's specific class requirements.

What Our Customers Say

★★★★★May 2026

"We replaced 6 mud door cylinders on our 6,500 m³ TSHD. The new cylinders with ceramic rod coating handle the continuous saltwater immersion during bottom discharge much better than our previous hard-chrome units. After 8 months, zero rod pitting."

Capt. L. Henriksen — Dredge Master, Denmark

★★★★★Jan 2026

"The integrated displacement sensor option was the deciding factor. Our automation system now controls mud door opening rate automatically based on material density — we get more consistent seabed placement on our beach nourishment projects."

Eng. R. Duarte — Systems Engineer, Portugal

★★★★☆Sep 2025

"Good quality cylinders at a competitive price. We operate 2 TSHDs in West African waters. The high-temperature seals handle 45°C ambient without issue. Minor delay on delivery (10 weeks vs quoted 8) but the cylinders themselves are well-made."

A. Mensah — Fleet Superintendent, Ghana

★★★★★Jun 2025

"Emergency order — our starboard mud door cylinder failed mid-project. Korea Ever-Power shipped a matched replacement in 5 weeks. It bolted straight into the existing mounting without modification. The project deadline was saved."

J. van den Berg — Project Manager, Netherlands

★★★★★Feb 2025

"Third TSHD we have fitted with Korea Ever-Power mud door cylinders. Consistent quality and documentation. The BV material certificates and test reports are always complete and on time."

Y. Li — Chief Engineer, Hong Kong-registered fleet

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