Self-Unloading Sand Barge | Design, Operation and Safety Requirements

2026-04-05 17:04:07     Category：Technical Resources     Browse number：120     Release time：2026-04-05 17:04:07

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Self-Unloading Sand Barge / Self-Suction & Self-Unloading Sand Barge(3 in 1 dredger)

1. Definition & Classification

Self-Unloading Sand Barge: Only equipped with sand transportation and unloading functions; no sand extraction equipment, pump, diesel engine, or suction pipe. It can only be loaded by external equipment and cannot extract sand on its own.

Self-Suction Self-Unloading Sand Barge (3-in-1 Dredger): Integrates sand extraction, transportation, and unloading. It is equipped with an independent sand suction system (diesel engine, sand pump, suction pipe) and can extract sand directly underwater.

Not all vessels are equipped with a sand suction device; only self-suction models have this configuration.

2. Structural Features

Both types adopt V shaped / hoppershaped cargo holds, allowing sand to slide to the bottom automatically for continuous unloading.

Core equipment: Hydraulic unloading door, longitudinal conveyor belt, elevator, rotating unloading arm, centralized control system in wheelhouse.

Sand suction system (self-suction only): Independent diesel engine, sand pump, suction pipe, mud box, drainage device, overflow system.

Safety structure: Hatch cover / wave breaker, drainage pump set, water level alarm, vision monitoring, safety walkway, fire-fighting system.

3. Working Principle

Sand Suction (Self-Suction Self-Unloading only)

Vessel berths at sand mining area → Lower suction pipe → Diesel engine drives sand pump → Extract sand-water mixture → Sedimentation and drainage in the hold → Loading completed.

Operation limit: Wind ≤ 6 levels, wave height ≤ 2 meters.

Unloading (All types)

Hydraulic unloading door opens (or wooden boards laid before loading are manually removed) → Sand falls by gravity → Conveyed by belt → Lifted by elevator → Unloaded or transferred via unloading arm.

The whole process is closed, continuous, and dust‑free, independent of shore cranes.

4. Operation Methods

Sand Suction & Loading (Self-Suction only)

The vessel operates independently at the mining area using its own diesel engine, pump, and pipeline system. It is limited to wind ≤ 6 levels and wave height ≤ 2 meters. Standard sand unloading barges cannot extract sand and must be loaded by external equipment.

Offshore Continuous Operation

Vessels operate at sea for a long time without returning to port. Fuel, water, and supplies are delivered by supply vessels. Sand is directly transferred to other cargo vessels at sea for sale, without berthing or customs declaration.

Self-Unloading

Controlled from the wheelhouse, the system unloads efficiently at 2,000–6,000 tons/hour (up to 7,000 tons/hour for large vessels). It can operate in shallow water, simple terminals, or offshore anchorage.

Offshore Transshipment

Unloading directly to other vessels via the arm without dock facilities, widely used in offshore sand supply, reclamation, and port construction.

5. Industry Situation Before 2020

Before 2020, many sand barges in Taizhou, Wenling and other coastal areas had no legal certificates. They failed to meet ZC / CCS rules in structure, stability, watertight integrity, fire protection, and escape routes. These vessels operated illegally at sea with high risks and frequent accidents.

6. Rules & Requirements (Effective 2020)

According to Rules for the Construction and Equipment of Sea-going Ships Engaged on Domestic Voyages (2020):

Steel weathertight hatch covers must be installed for cargo holds and sand outlets.

Minimum freeboard: ≥ 1.5 m for coastal vessels; ≥ 1.0 m for sheltered waters.

Wave breaker must be fitted to full breadth with sufficient strength.

Collision bulkhead must be intact; recess in bow ≤ 1/5 of ship breadth.

Cargo drain pumps: ≥ 4 working + 1 standby, with independent power.

Audible and visual alarm at bilge water ≥ 300 mm; automatic start at ≥ 200 mm.

Wheelhouse blind area ≤ 3× length or 500 m, with night-vision waterproof camera.

Certificate to note operation restriction: wind ≤ 6 levels, wave ≤ 2 m.

Safety operation notice must be posted on board.

7. Safety Requirements

V shaped holds lead to high center of gravity; overloading, raising coamings, and excess loading are strictly prohibited.

Free surface effect from bilge water and wet sand must be controlled to avoid stability loss.

Watertight / fireresistant bulkheads and hull structures must not be damaged.

Hatch covers must maintain weathertightness with intact gaskets and effective locking.

Conveyors outside deck must be securely fixed; safety walkway must be provided above sand holds.

Unauthorized washing pumps, pipe modification, and illegal sand washing are prohibited.

8. Typical Domestic Projects

Uncertified barges in Taizhou & Wenling (before 2020): Illegal offshore extraction and transshipment.

106m self-suction self-unloading sand barge in Fujian: Built in accordance with 2020 rules.

89.8m Run Series: First legally compliant sand barges in China.

2,400ton inland river barge in the Pearl River Delta: 2,500 tons/hour unloading.

9. Typical Overseas Projects

Maharathi (Liberia, Africa): 100,000-ton gravity selfunloading vessel, 7,000 tons/hour.

Indonesia: Wide use of selfunloading barges for coal and sea sand transport.

Orinoco River (Venezuela): Selfunloading vessels for iron ore transshipment.

10. Application Scenarios

Offshore sand mining, transportation, and transshipment.

Port expansion, channel dredging, reef and rock removal.

Land reclamation, artificial island, and port area development.

Inland sand transportation (Yangtze, Pearl River).

Engineering sand supply and overseas bulk material selfunloading.