MARINE / TRENDING TOPIC / ASIA PACIFIC
Floating docks in modern shipyards
How floating docks work
Weighing the benefits and drawbacks
Location matters
What can go wrong during operation?
Keeping floating docks in good shape
Liberty's approach
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Risk analysis and management of floating dock operations
In the maritime industry, where safety is paramount, understanding potential hazards and essential mitigation strategies is crucial. This article delves into the operational mechanics of floating docks, examining their associated risks, advantages, and limitations.
Weighing the benefits and drawbacks
Floating docks have their pros and cons. They offer several benefits over conventional graving docks, including reduced construction costs. However, they also face challenges such as a shorter lifespan.
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Last updated 04/2025
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Floating docks in modern shipyards
Imagine a giant, floating platform in a shipyard; that is a floating dock. In the maritime industry, floating docks represent a versatile and essential component of modern shipyards, offering a flexible docking solution without permanently altering waterfront landscapes. However, operating these structures involves inherent risks, including structural failures, environmental factors, and operational errors, which can lead to significant negative consequences. For underwriters and marine brokers, understanding these risks is crucial for accurately assessing exposure and developing insurance products that protect stakeholders involved in shipyard operations.
Floating docks are engineered to float, submerge to receive ships, and refloat to lift them clear of the water, making it easier to repair and maintain vessels, particularly the underwater components and hull areas that are difficult to access when the ship is afloat. They range from small structures to massive ones, capable of docking vessels with deadweights up to 130,000 tonnes.
How floating docks work
Each floating dock comprises two wing walls and a docking pontoon, designed as box-shaped structures divided into multiple longitudinal and transverse watertight spaces by bulkheads. The docking pontoon is the main structure that displaces the vessel's weight through buoyancy, while the wing walls stabilise the floating dock when submerged, contributing to longitudinal strength and weight distribution. A system of pumps, pipes, and valves controls the filling and emptying of ballast tanks, allowing the floating dock to submerge or refloat. The process can take between two to six hours, depending on pump capacity. Most floating docks are semi-permanently moored with piles and connected to a jetty by a ramp, while some are towed to deeper waters for loading and discharging operations.
Advantages
Disadvantages
Reduced initial construction costs.
Faster construction timelines allow for quicker operational readiness.
Does not require permanent waterfront occupation, freeing up valuable estate.
Enhanced mobility facilitates relocation to different sites as operational needs change.
Marketability and ease of transfer facilitate asset liquidity.
Capability to operate with slight list or trim offers operational flexibility.
Generally shorter lifespan than conventional graving docks, leading to more frequent replacements.
Vulnerability to significant tidal fluctuations and wave action necessitates careful site selection and operational planning.
Increased maintenance expenditures due to machinery wear and the need for rigorous corrosion protection.
Lack of ability to partition limits simultaneous docking operations.
Restricted access via ramp can complicate logistical and personnel movement.
Complex docking and undocking procedures demand skilled operators and precise coordination.
Location matters
Where a floating dock is located can make a big difference in the risks it faces. Despite their stationary nature, floating docks face significant risks under certain circumstances.
For instance, in busy shipping hubs like Singapore, the associated hazards from passing ships and vessel launching activities are significant and warrant careful consideration. Additionally, floating docks in typhoon-prone regions face similar challenges. For shipyards on riverbanks, floating docks are frequently towed to deeper waters for docking operations, and risks are heightened. These include the possibility of foul weather, adverse currents, collisions with other vessels, and grounding during transit. The docking process becomes more complex, given that it involves maneuvering between two moving entities—a vessel and a floating dock.
In Singapore, two floating docks sustained damage to their side shell plates, securing piles, and ramps due to waves generated by a third-party vessel. This vessel, returning from a sea trial at excessive speed, passed close to a floating dock moored at a nearby shipyard. The waves created by the vessel caused the floating dock to roll significantly, resulting in damage. A similar incident occurred with a newly-built jack-up unit launched from an opposing shipyard, generating waves that impacted the nearby floating dock.
Learning from past incidents: geographical risks
A floating dock sank in Sarawak when it was accidentally trimmed excessively during a docking operation. This misalignment caused the vent pipe opening to submerge in water, leading to rapid compartment flooding. Similarly, at a shipyard on Batam Island, another floating dock sank due to inaccurate positioning of keel blocks. As the floating dock emerged from the water and started taking load, several blocks punctured the pontoon deck, causing multiple ballast tanks to flood, resulting in a rapid loss of buoyancy and subsequent sinking.
Submerged floating docks have minimal reserve buoyancy, making them sensitive to unplanned weight shifts or improper ballasting sequences due to the relatively limited waterplane area provided by the wing walls. Malfunctions in valves or ballast pumps can exacerbate these vulnerabilities, leading to uneven ballasting. This uneven distribution of weight can cause excessive trimming, listing, and structural stresses, which may result in rapid loss of buoyancy and potential sinking.
What can go wrong during operation
Learning from past incidents: operational risks
Floating Dock Crane
The pontoon deck supports the weight of vessels during docking operations and acts as a platform for service activities. It is essential to maintain the integrity of the pontoon to withstand both static and dynamic load from ships.
Safety Deck
Wing Wall
Pontoon Deck
Wing Wall
Pump Room
Safety Deck
Watertight Bulkheads
Submerged Draft
Operating Draft
Wing Deck
Control Room
Ship Centre of gravity
Docking Pontoon
The floating dock crane plays a key role in loading and unloading heavy equipment and materials. This high-capacity crane can lift between 10 to 30 tonnes and is engineered to swivel and move on rails along the length of the dry dock.
Floating Dock Crane
Pontoon Deck
The docking pontoon is equipped with multiple ballast tanks, separated by longitudinal and transverse bulkheads. This design allows the floating dry dock to be ballasted down or up while maintaining a level position.
Docking Pontoon
Located at the top of the wingwall, the control room provides a bird's-eye view of the docking operations. It serves as the nerve centre for all activities within the floating drydock. Equipped with controls for the ballasting system and monitoring water levels, it features CCTVs and a communication system that allows operators to directly monitor and communicate with crew members.
Control Room
The pump room houses essential pumping systems for ballasting and de-ballasting operations. It is equipped with high-capacity pumps that quickly adjust water levels to facilitate the safe and efficient launch and retrieval of vessels. Regular maintenance and inspections of equipment within this room are crucial to prevent operational disruptions and ensure compliance with safety standards, safeguarding both personnel and docked vessels.
Control Room
The durability of floating docks depends heavily on regular maintenance. Pontoon decks are prone to mechanical abrasion, welding heat, and general wear, which can compromise protective coatings and accelerate steel deterioration, affecting structural integrity. This increases vulnerability to damage from improper ballasting or loading, or in extreme cases, results in the total loss of the structure.
Keeping floating docks in good shape
Liberty’s approach
Understanding the complexities of floating dock-related marine risks demands expertise and a tailored approach to insurance. At Liberty, our team of highly qualified risk engineers provides invaluable insights into the intricacies of the maritime industry. With decades of experience and profound marine insurance knowledge, we deliver comprehensive support to foster peace of mind and instill confidence in our clients' marine operations.
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Working with us means you’re drawing on more than 110 years of experience evaluating, pricing and managing risks for most types of assets – from warships, shopping centres and oil rigs, to power plants, office towers and boards of directors.
Together we can help you embrace the challenges of today, pursue the opportunities of tomorrow, and protect what matters most.
At Liberty Specialty Markets, our risk engineers and claims team work closely with the underwriters to provide seamless support for our clients.
The claims handling for marine is managed by our Claims Manager, Penny Chua, who has more than 15 years of experience.
Our Senior Risk Engineer, MK Cheah, has worked in major shipyards for over a decade and has a wealth of knowledge and practical experience to support comprehensive risk assessments, mitigation strategies, and informed marine underwriting decisions.
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Liberty is not authorised to provide financial product advice. The information in this document does not take into account your objectives, financial situation or needs. Always consider the applicable policy wording and other relevant documents before deciding to acquire a financial product.
This document is intended to broadly illustrate the kinds of exposures a business can face in respect of allocation clauses. It is not a comment on insurance coverage available from Liberty. It is intended to provide general information and commentary and should not be relied upon as legal advice. You should not rely on this information without first obtaining professional advice.
Liberty means Liberty Specialty Markets, a trading name of Liberty Mutual Insurance Company, Australia Branch (ABN 61 086 083 605; AFSL No. 530842 (for claims handling and settling services only)) incorporated in Massachusetts, USA (the liability of members is limited); Liberty Specialty Markets Hong Kong Limited (UBI 66395065); Liberty Specialty Markets Singapore Pte Limited (UEN 201538069C); and Liberty Specialty Markets Singapore Pte Limited, Labuan Branch (Company No. LF12903), a licensed insurer under the Labuan Financial Services and Securities Act 2010 (Licence No. IS2016162).
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MK Cheah
Senior Risk Engineer, Marine Liberty Specialty Markets
“
From a risk management perspective, evaluating floating docks involves verifying compliance, scrutinising specifications and history, assessing maintenance records, and evaluating the physical condition of the dock and crew competence. This comprehensive approach identifies vulnerabilities and potential risks, leading to targeted recommendations that enhance operational safety.
“
Lewis Yang
Assistant Vice President, Marine and Exploration & Production Liberty Specialty Markets
“
Floating docks represent a key segment of our hull and machinery portfolio, complementing our offerings on the shipyards and ship repairers’ liability segments. With our in-house engineering capabilities, we are confident in our ability to manage associated risks effectively. This expertise not only adds value to our customers and partners but also enables them to leverage Liberty's extensive experience in this field.
“
Control Room
Control Room
Control Room
Control Room
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