Floating Crane (Crane Vessel): Definition, Classification and Development

Floating Crane (Crane Vessel )

I. Basic Definition and General Information

A floating crane is a crane supported and operated by a self-propelled or towed special floating ship hull, also known as a crane vessel or floating crane.

Inland river ports generally use non-self-propelled crane vessels. Various types of cranes are installed on the deck of a pontoon barge, equipped with ship mooring equipment and living facilities. Small and medium-sized floating cranes are usually powered by shore electricity; self-propelled versions must be fitted with a propulsion system.

II. Core Components

A floating crane generally consists of two main parts: the lower floating hull and the upper structure mounted on the deck.

Floating hull: Supports the self-weight of the crane and the lifted load, transfers loads to the water through the hull, and can move along waterways or shift horizontally in the operating area.

Upper structure: The lifting device of the floating crane, used for loading, unloading, or hoisting cargo.

III. Standard Classification (According to GB/T 6974.7-2022 Cranes – Vocabulary – Part 7: Floating Cranes)

1. By Navigation Mode

Self-propelled floating crane: Capable of independent navigation.

Non-self-propelled floating crane: Relies on tugboats for towing.

2. By Power Plant

Classified into internal combustion engine-driven floating cranes and shore-powered floating cranes, differing in power source. Further divided by drive mechanism:

Internal combustion electric floating crane

Internal combustion hydraulic floating crane

Shore-powered electric floating crane

Shore-powered hydraulic floating crane

Internal combustion hydraulic floating crane: Uses a hydraulic station driven by an internal combustion engine as the power unit; working mechanisms are hydraulically driven.Shore-powered electric floating crane: Uses shore-based power; working mechanisms are electrically driven.

3. By Slewing Capacity

Non-slewing floating crane:

The jib is rigidly connected to the hull and cannot slew relative to the hull, divided into luffing jib and fixed jib types. It relies on luffing (changing the jib angle) to change the working radius. The Gin pole crane (Gin pole type crane vessel) is the typical representative of this type.

Slewing floating crane: The jib can rotate relative to the hull. This is the mainstream type, subdivided into full-circle slewing (≥360°) and limited slewing (<360°).

4. By Overall Structural Form

High-frame jib floating crane:

A type of slewing jib floating crane, where the slewing unit is supported on a fixed high structure on the hull deck.

5. By Jib Form

Single jib floating crane:

Subdivided into telescopic jib, fixed-length jib, and single jib with auxiliary jib.

Double jib floating crane

Combined jib floating crane:

Jib system includes jib, elephant nose, and tie rods. The front end of the elephant nose remains nearly constant during luffing, and the load attachment moves along an approximately horizontal path.

6. By Jib Section Form

Box girder jib floating crane

Tubular jib floating crane

Truss jib floating crane

7. By Load Attachment

Hook floating crane

Grab floating crane

Container floating crane

Lifting magnet floating crane

8. By Application

Handling floating crane

Shipbuilding floating crane: Used for ship launching and outfitting in shipyards.

Installation floating crane: Used for shore equipment, hydraulic structures, bridges, wind power, etc.

Salvage floating crane

9. By Operating Water Area

Harbor floating crane: Operates in harbors, inland waterways, shipyards.

Offshore floating crane: Operates, tows, and lifts in offshore areas.

Deep-water floating crane: Operates, tows, and lifts in deep and distant seas.

IV. Mechanisms and Key Components

Jib Luffing & Stowage System:

Luffing Mechanism: Raises or lowers the jib to change the working radius.

Stowage (Lowering) Mechanism: Temporarily lowers the jib system to reduce height for bridge clearance or to lower the center of gravity for long-distance towing.

Jib Transfer Device:

Moves the lowered jib longitudinally toward the midship (centerline) to improve vessel stability during transit. (Note: Primarily used in non-slewing/Gin pole cranes).

Hoisting Drum:

Typically uses a Lebus drum (or grooved drum),

featuring alternating left- and right-hand helical grooves (Lebus drum) to ensure orderly multi-layer rope winding and prevent rope pinching.

V. Structural and Design Requirements

Large crane vessels usually have large principal dimensions. A 4000t-class crane vessel has a displacement of about 70,000–80,000 tons. Structural design must consider the most unfavorable load combination under operating conditions with sufficient strength reserve.

Hull Strength: High overall loads and uneven local stress concentrations require high structural strength. Reinforced structures (pedestals) are essential under the crane to transfer concentrated loads effectively.

Longitudinal Members: Should be continuous from bow to stern, generally with two or more full-length longitudinal bulkheads or trusses.

Transverse Bulkheads: Arranged according to subdivision and damage stability requirements.

Stability: Principal dimensions are determined by lifting capacity, allowable heel angle, and deck loads.

Typical hoisting speeds:

Kiloton class: approx. 1 m/min

Hundred-ton class: approx. 4 m/min

Ten-ton class: approx. 8 m/min

Roll, pitch, and heave must be minimized during operation. The vessel can adopt pontoon buoyancy assist to reduce operating draft and enable shallow-water operation. Green and intelligent technologies such as photovoltaic energy storage, high-efficiency permanent magnet motors, and energy feedback are applied for development toward green and intelligent operation.

VI. Main Functions and Application Scenarios

Floating cranes are engineering vessels dedicated to water lifting operations, mainly performing water lifting and heavy cargo transport tasks beyond the capacity of land equipment:

Mega projects and marine development: bridge construction, port and terminal works, submarine pipeline laying, installation and dismantling of offshore oil platforms.

Port logistics and ship operations: ship-to-shore and ship-to-ship cargo handling, large ship section hoisting in shipyards, suitable for inland ports with large water level variations.

Rescue and salvage: wreck salvage, waterway obstacle removal, emergency rescue at sea.

Heavy cargo transfer: loading/unloading of large machinery and steel structures at temporary docks or remote waters.

Classified by operation type:

Handling type: Mostly used in inland ports, high speed and efficiency for fast bulk cargo handling.

Lifting type: For heavy, large, high, deep conditions, slow motion, high lifting capacity, capable of precise integral hoisting.

VII. Parts of Major Crane Vessels in China

Zhenhua 30: 12,000-tonne full-slewing single-jib crane vessel, the world’s largest crane vessel. It has participated in mega marine projects including the Hong Kong-Zhuhai-Macao Bridge island-tunnel project.

Blue Whale: 7,500-tonne full-slewing crane vessel, once the world’s largest single-hook full-slewing crane vessel. Used for offshore wind power, bridge construction, pipe laying, salvage, etc.

Erhang Zhuoyue: China’s largest double-jib luffing crane vessel, invested by CCCC Second Harbor Engineering and built by ZPMC, delivered in September 2024.

Chuangli: 4,500-tonne self-propelled crane vessel, used for installation of large offshore modules, platform modules, wind turbine steel piles and jackets, and also for wreck and sunken object salvage.

Huatianlong: 4,000-tonne full-slewing floating crane, once Asia’s largest floating crane, suitable for severe sea conditions, expanding marine engineering and salvage capabilities.

Samsung No.5: 8,000-tonne double-jib floating crane, exported to South Korea in 2010, then the world’s largest double-jib floating crane, used for ship block lifting and offshore platform module transport & installation.

Xinzhenfu 7: 5,000-tonne fixed-jib crane vessel with lifting and transport functions, used for offshore wind turbine transport and offshore booster station module hoisting.

Tuoyou: 2,000-tonne self-propelled crane vessel, used for offshore wind installation and lifting operations.

Liyang Offshore 5000-tonne Crane Vessel: Equipped with a 5000-tonne fixed stern crane and 3500-tonne full-slewing crane, DP1 dynamic positioning, serving wind power, bridge construction and salvage.

Jiangsu Longsheng 4000-tonne Crane Vessel: Integrated transport & construction wind power vessel, max 4000-tonne stern crane / 3000-tonne full-slewing crane, for 15MW+ wind power foundation construction.

CCCC Third Harbor 4000-tonne Crane Vessel: 4000-tonne fixed stern crane / 3000-tonne full-slewing crane, DP2 dynamic positioning, for wind power foundation and offshore component installation.

VIII. Development Overview (Domestic & International)

International

Large crane vessels greatly shorten offshore engineering cycles, reduce costs and improve safety. Major manufacturing countries include Japan, South Korea, China, Norway, etc.
Vessel types include oil tanker conversions, self-propelled crane-pipe layers, and semi-submersible crane vessels (third-generation full-slewing crane vessels with excellent seakeeping, suitable for deep water but high cost).

Domestic

Early stage was dominated by small gin-pole barges with low lifting capacity, mainly used in inland shallow waters. Later small full-slewing cranes were gradually adopted, and a large number of 30t–300t full-slewing crane vessels were built.Large fixed gin-pole crane vessels reached a lifting capacity of thousands of tonnes.

At present, China has the capacity to build 10,000-tonne class crane vessels. Driven by offshore development, bridge construction, offshore wind power, platform decommissioning, etc., the market demand for ultra-large offshore engineering lifting systems continues to expand.