What is Dunnage?
Dunnage is timber used to prevent metal to metal contact between cargo and the ship’s hold or between steel plates and to stop loose items from moving around in the hold during the voyage.
Dunnage is a bit of wood, sacking, inflatable rubber bags, in fact, anything which is used to prevent damage to the cargo.
Stowage is an integral part of the loading and is therefore the shipowner’s responsibility unless there is a term in the charter-party transferring it to the charterer. Stowage includes arranging and securing the cargo in such a way as to prevent damage or deterioration to any of the cargo loaded.
In addition, materials such as dunnage, wooden planks and timber used to keep bagged cargoes or cases away from the steel hull or to act as a separation between different cargoes, lashing wires, and ropes must be provided to achieve the safety of the cargo and ship.
Where loading or discharging is to be carried out at more than one port, the ship must be seaworthy and have a proper trim, draught of the ship forward and aft to allow efficient use of the propeller and rudder, whilst steaming between the interim ports. Some current seaworthy trim clauses render the charterers liable for the costs of ensuring seaworthy trim.
What is Dunnage in Dry Bulk Shipping?
Dunnage is a term used in dry bulk shipping to refer to the materials used to protect and secure cargo during transportation. The primary purpose of dunnage is to prevent the cargo from shifting, chafing, or getting damaged due to moisture or other environmental factors during the voyage. It also helps to distribute the weight of the cargo evenly and ensure efficient and safe stowage within the vessel’s cargo hold.
Dunnage materials can be made from various materials, including:
- Wood: Wooden dunnage, such as timber, plywood, or wooden pallets, is commonly used to create separation between different types of cargo or to elevate cargo from the floor of the cargo hold. This prevents direct contact with the hold’s surface, reducing the risk of damage due to moisture or condensation.
- Airbags or inflatable dunnage: These are used to fill gaps and secure cargo by providing cushioning and preventing movement during transit. They are made of durable materials and can be inflated to the required size to fit specific spaces.
- Foam, rubber, or plastic: These materials can be used in the form of padding, sheets, or blocks to provide additional protection to delicate or sensitive cargo. They offer cushioning and shock absorption, reducing the risk of damage due to vibrations or impacts during the voyage.
- Corrugated cardboard: Cardboard can be used to create separation between cargo items or layers, providing additional protection against chafing and abrasion.
- Paper, cloth, or other flexible materials: These can be used to wrap individual items or create a barrier between different types of cargo, offering protection from moisture, dirt, or other contaminants.
The choice of dunnage depends on the specific cargo being transported, the vessel’s design, and the requirements of the loading and unloading operations. Proper use of dunnage is essential to ensure the safe transportation of dry bulk cargo and minimize the risk of damage during the shipping process.
Selecting and Using Dunnage in Dry Bulk Shipping
When selecting and using dunnage in dry bulk shipping, several factors must be taken into consideration to ensure optimal cargo protection and efficient stowage:
- Cargo characteristics: The type, weight, size, and shape of the cargo, as well as its sensitivity to moisture, temperature, and other environmental factors, must be taken into account when choosing the appropriate dunnage materials.
- Load distribution: The dunnage should be placed strategically to distribute the weight of the cargo evenly across the vessel’s cargo hold, minimizing the risk of overloading or imbalanced loading that could compromise the ship’s stability.
- Ventilation and moisture control: The use of dunnage should allow for adequate air circulation within the cargo hold, preventing the buildup of condensation or moisture that could damage the cargo or lead to mold and mildew growth. This is particularly important for cargoes that are sensitive to humidity, such as agricultural products or metals prone to corrosion.
- Compatibility with cargo handling equipment: Dunnage materials should be compatible with the cargo handling equipment used during loading and unloading operations, ensuring efficient and safe transfer of cargo on and off the vessel.
- Reusability and environmental considerations: In recent years, there has been a growing emphasis on using environmentally friendly and reusable dunnage materials to minimize waste and reduce the environmental impact of shipping operations. These materials can include recyclable or biodegradable options, such as paper or cardboard, as well as reusable items like rubber mats or inflatable airbags.
- Cost-effectiveness: The choice of dunnage should strike a balance between providing adequate protection for the cargo and being cost-effective. The right dunnage solution can help minimize cargo damage and associated costs, such as insurance claims, delays, or cargo rejection at the destination port.
The use of dunnage in dry bulk shipping is crucial for ensuring the safe and efficient transportation of cargo. By considering factors such as cargo characteristics, load distribution, ventilation, compatibility with cargo handling equipment, environmental considerations, and cost-effectiveness, shippers can select and use the most appropriate dunnage materials to protect their cargo and optimize the shipping process.
What is Dunnage Wood in dry bulk ships?
Dunnage wood refers to wooden materials used in dry bulk ships to protect, support, and secure the cargo during transportation. The primary function of dunnage wood is to prevent the cargo from shifting, chafing, or getting damaged due to moisture or other environmental factors during the voyage. It is a common and traditional type of dunnage used in the shipping industry.
Dunnage wood can come in various forms, such as:
- Timber or lumber: These are solid pieces of wood, cut and shaped to specific dimensions, used to create separation between different types of cargo or to elevate the cargo from the floor of the cargo hold. This prevents direct contact with the hold’s surface, reducing the risk of damage due to moisture or condensation.
- Wooden pallets: These are flat, rigid structures made of wood, used as a base for stacking and transporting cargo. Pallets can be placed on the floor of the cargo hold to elevate and protect the cargo from moisture, while also making it easier to handle during loading and unloading operations.
- Wooden boards or plywood: These are thin sheets of wood, often used to create barriers or partitions between different types of cargo, providing protection against chafing and abrasion.
When using dunnage wood in dry bulk ships, it is essential to consider the following factors:
- Treated or untreated wood: Depending on the type of cargo and its sensitivity to moisture or pests, it may be necessary to use treated wood to prevent the growth of mold, mildew, or the infestation of insects.
- Load distribution: Wooden dunnage should be placed strategically to distribute the weight of the cargo evenly across the vessel’s cargo hold, minimizing the risk of overloading or imbalanced loading that could compromise the ship’s stability.
- Environmental considerations: Although wooden dunnage is reusable, it may not always be the most environmentally friendly option, particularly if sourced from non-sustainable or non-certified sources. In recent years, there has been a growing emphasis on using environmentally friendly and reusable dunnage materials to minimize waste and reduce the environmental impact of shipping operations.
Dunnage wood is a traditional and widely used form of dunnage in dry bulk ships, providing protection, support, and stability for the cargo during transportation. It is essential to select appropriate wooden dunnage materials and use them correctly to ensure the safe and efficient transportation of cargo.
What is Hardwood Dunnage and Softwood Dunnage in Dry Bulk Ships?
Hardwood and softwood dunnage are two types of wooden materials used in dry bulk ships for protecting, supporting, and securing cargo during transportation. Both hardwood and softwood dunnage serve similar purposes, such as preventing cargo from shifting, chafing, or getting damaged due to moisture or other environmental factors during the voyage. However, they differ in terms of their physical properties and suitability for specific applications.
- Hardwood Dunnage:
- Hardwood dunnage is made from the wood of deciduous trees, such as oak, teak, or maple. These trees typically have a slower growth rate and produce denser, heavier, and more robust wood.
- Due to its strength and durability, hardwood dunnage is often used in applications where higher resistance to wear and tear, weight-bearing capacity, or moisture resistance is required.
- Hardwood dunnage may be more expensive than softwood dunnage due to the higher costs associated with sourcing and processing the wood.
- Some examples of hardwood dunnage applications in dry bulk ships include creating separation between heavy or abrasive cargoes, providing support for cargo that requires a more robust base, and offering increased resistance to moisture in damp or humid environments.
- Softwood Dunnage:
- Softwood dunnage is made from the wood of coniferous trees, such as pine, spruce, or fir. These trees typically have a faster growth rate and produce lighter, less dense wood.
- Softwood dunnage is generally more cost-effective and easier to work with than hardwood dunnage. However, it may be less durable and resistant to wear and tear, making it more suitable for lighter or less abrasive cargo applications.
- Softwood dunnage can be used for creating separation between lighter cargoes, elevating cargo from the floor of the cargo hold, and constructing partitions or barriers between different types of cargo.
- It is essential to ensure that the softwood dunnage used in dry bulk ships is appropriately treated to prevent the growth of mold, mildew, or the infestation of insects.
When selecting between hardwood and softwood dunnage for use in dry bulk ships, factors such as the type, weight, and sensitivity of the cargo, as well as the specific requirements of the shipping operation, must be taken into consideration. By choosing the appropriate type of wooden dunnage and using it correctly, shippers can ensure the safe and efficient transportation of cargo in dry bulk ships.