1. Introduction
The maritime industry continues to see a considerable increase in the number of maritime incidents involving the loss of cargo, ships, and human life. Today, merchant ships have become increasingly complex, with various systems being equipped to make them more efficient, safer, and easier to operate. However, this has also made the concept of seaworthiness more complex and confusing. The standards and requirements of seaworthiness have caused widespread debate and even disputes.
The narrow sense of seaworthiness is usually from the perspective of the ship structure and design, rarely considering other aspects. Based on the implementation of international conventions and other relevant regulations, the concept of seaworthiness has been extended. For example, Zhang [
1] investigated the relationship between crew factors and ship seaworthiness under the Maritime Labour Convention, 2006 (MLC 2006). In a broad sense, the seaworthiness of a ship refers to its ability to carry cargo out of the wharf and transport cargo safely. As a result, crew factors, environmental factors, management factors, ship factors, and cargo factors should be considered component factors of ship seaworthiness. However, until now, there has not been any research on the seaworthiness of ships specifically focusing on the characteristics of the cargo.
Solid bulk cargoes have special physical and chemical properties. They are easy to couple with carriers during the shipping process. For example, some cargoes may liquefy and undermine the stability and safety of the ship. The disaster of the M.V. Bulk Jupiter had a profound impact on the industry. It was a Handymax carrier with 46,400 Tons of bauxite that capsized and sank with 18 crew members on 2 January 2015 [
2]. A series of efforts were undertaken by the industry to improve the safety of bauxite transportation in the following years. The 2019 amendments of the International Maritime Solid Bulk Cargoes Code (IMSBC Code), entering into force on 1 January 2021, represent a significant outcome of the industry collaboration. However, it remains to be seen if the 2019 amendments deliver their intended objectives.
This paper aims to critically examine the seaworthiness of bauxite carriers related to the 2019 amendments. For this purpose, the following objectives are achieved:
Reviewing the development of the doctrine of seaworthiness in maritime law, in particular the important role of cargo property in ensuring the seaworthiness of ships;
Examining the implications of implementing the 2019 amendments of the IMSBC Code, particularly its role in improving the safety of bulk bauxite carriers;
Analysing the extension of the meaning of seaworthiness under the impact of the IMSBC Code, in particular the changes to standards under the new requirements of the 2019 amendments;
Assessing the criticisms of this extension and the major obstacles existing in law and practice.
2. Literature Review
Between 1988 and 2019, a total of 25 accidents were recorded in bulk carriers due to the liquefaction of the cargo, and 19 of the recorded accidents resulted in capsizing as the ships lost their stability [
3,
4]. Considering that these accidents were caused by cargoes that may liquefy, many researchers have explored the transportation safety of bulk carriers in relation to the interaction between mineral ore and its carriers.
Related to the loading conditions and behaviour during transportation, the performance of mineral cargoes is an important factor in the seaworthiness of bulk carriers, as shown by previous accidents caused by the liquefaction of the cargo in bulk carriers [
5]. Cargo liquefaction is a direct result of the correlation between the parameters of the moisture content (MC) inside the cargo and the movement of the ship, manoeuvring to respond to weather conditions at sea. The only available parameter used to prevent liquefaction from occurring is the transportable moisture limit (TML). At present, simulation experiments of cargo characteristics are usually carried out to reveal the disaster mechanism of cargo characteristics from the perspective of engineering safety. Munro M.C. [
6] examined the collective causes of the liquefaction of solid bulk cargoes to prevent the ingress of water into the cargo during transportation, loading, and storage. Through a review of the three test methods stated in the 2013 IMSBC Code, Munro M.C. [
7] found that none of them were suitable for evaluating iron fines. To further refine the modified Proctor/Fagerberg test (MPFT) to determine the TML of iron ore fines, Munro M.C. [
8] investigated 23 incidents originating from bulk cargoes that liquefied during transportation and caused the loss of human life and industry assets, and they proposed improving the modified Proctor/Fagerberg test (MPFT) to determine the TML of iron ore fines. Ju L. [
9] developed a liquefaction model to predict the ship’s stability and evaluate potential hazards during the marine transport of solid bulk cargo. Sakar C. [
10] analysed the liquefaction risk and the other fundamental causes resulting from the capsizing of bulk carriers using an integrated risk assessment method with the integration of interpretive structural modelling and fuzzy Bayesian networks. Improper loading, a lack of cargo care, and insufficient knowledge arising from human error play a critical role in cargo liquefaction. For the preparation before the cargo loading stage, Zhang D.H. [
11] proposed a revised evidential reasoning approach to cope with the complex decision making in cargo stowage plans. In order to reduce the risk of capsizing and reclaim the stability of a Handymax bulk carrier with nickel ore, Lee H.L. [
12] developed a response plan for a liquefaction incident that would redistribute homogeneous stowage. Based on an overview of the behaviour of iron ore cargoes during marine transportation, Mohajerani [
13] explored the reasons behind some listing and capsizing incidents and implemented some possible solutions and recommendations to reduce cargo shift. Based on a 3D simulation, Wu W. quantified the risk of cargo liquefaction roughly, quickly, and dynamically [
14]. Airey D.W [
15] used a fully coupled dynamic finite element analysis, simulated cyclic loading, and simultaneous consolidation and drainage, and then obtained the destructive factors of the stability of the ship and cargo.
Shipping practice shows that liquefaction is a phenomenon triggered by ship movements, where solid bulk cargo produces high-density, viscous liquid in the hold. Liquefaction can occur in iron ore or nickel ore due to excessive dynamic loading, vessel vibration, and rough seas. However, the Global Bauxite Working Group found that bauxite does not simply liquefy, even under worst-case shipping conditions [
16]. The instability of bauxite is referred to as dynamic separation, and its influence is fundamentally different from that of liquefaction [
17]. Both liquefaction and dynamic separation are caused by excessive moisture in the bauxite cargo, particularly the presence of highly fine particles that tend to absorb more water than granular particles, which may cause liquefaction [
18]. The performance of liquefaction and dynamic separation, called dynamic instability, destroys the stability of a ship and can even cause it to capsize [
19]. Bauxite properties are similar to those of traditional liquid cargo. If the moisture content is not properly controlled, it can release moisture to form a free surface, such as that in group A, which can reduce the stability of the ship and even cause it to capsize. Although bauxite was recorded as group C within the 2019 amendments to the IMSBC (yet the bauxite powder is classified as group A in the IMSBC Code due to the moisture content of which is generally approximately 15%) [
20], it has garnered attention since the M.V. Jupiter accident at the beginning of 2015. Before that, none of the incidents onboard bauxite bulk carriers resulted in losses to vessels or crew members since 2 July 2013, according to information from the North P&I Club. Hence, as a key factor in the accident, the relationship between the transportability of bauxite and the seaworthiness of ships ought to be a serious area of consideration.
According to research in the literature, the earliest research paper on bauxite transportation safety was in 1978. Anon [
21] discussed the development of and changes in efficient bauxite-handling equipment and transport ship types. Miyazawa and Masaru [
22] developed a special bauxite transport vessel based on the hydrodynamic effect of shallow water along the northeast coast of Australia through model tests of resistance, self-propulsion, wake measurement, and a cavitation test. Portella et al. [
23] applied the innovative concept of “single pour, single pass” drainage and loading synchronization to a bauxite carrier with 80,000 DWT to reduce the unacceptable stress superposition on the hull structure during single-hold loading and to ensure structural safety in the ship’s operation. Research on bauxite liquefaction has also been published in recent years. From the perspective of maritime management practice of bauxite shipping safety, Wu J. [
24] proposed a high-density slurry effect to evaluate the stability risk of bauxite carriers. Chen Z. [
25] gave several suggestions to ensure the strengthening of bauxite shipping safety management. As a sample, Gebeng bauxite was further researched under the IMSBC Code by Hasan M. [
18], and an understanding of several properties, including particle size distribution, moisture content, and specific gravity, was gained. Wu J. [
26] examined the transportation process of a bauxite carrier using the Markov chain method at different stages of loading, unberthing, departure, and sea navigation, and then revealed the risk evolution of the solid bulk cargoes with potential liquefaction during the bauxite shipping process. Wu J. [
27] developed an approach to reasoning about risk performance with a hidden Markov model and a prewarning system for the improvement of bauxite shipping process safety.
In general, although there have been studies on the subject of the dynamic instability of bauxite at sea, there are few systematic investigations into the management of seaworthiness in the study of the ocean transportation of bauxite. This paper mainly focuses on improving the understanding of the risk of the liquefaction of bauxite that may occur during shipment by interpreting the 2019 amendments of the IMSBC Code. A method of securing the seaworthiness of ship operation is proposed to comply with the standards under the IMSBC Code. The research defines several parts to clarify the definition of seaworthiness and describes seaworthiness in terms of shipbuilding, related equipment, cargo loading, maritime problems, customs and procedures, cargo management, and external inspection. In the following sections, a discussion and some recommendations concerning seaworthiness are provided from the preshipment stage and the shipping stage to the operation stage during the process of transportation.
5. Recommendations
5.1. Seaworthiness Management Framework for Logistics Chain of Bauxite
Considering the 2019 amendment of the IMSBC Code, the seaworthiness management of bauxite ocean transportation ships is a systematic project that requires the safety and quality management of the whole chain and the whole process. In addition to the transportability management of bauxite and the cargo worthiness management of ships, the following items should be involved in the whole logistics chain: bauxite production enterprises, shippers, carriers, terminal handling enterprises, transportation administrative authorities, and third-party organizations.
Figure 3 shows the framework of sea worthiness management for bauxite carriers.
In the whole logistics chain management, different bodies undertake corresponding responsibilities at each link. For shippers, sufficient, objective, and scientific cargo information and certificates must be provided for group A cargo with an IMSBC code, a qualification can be determined with instructions from the P&I Club, or through the selection of a surveyor; in particular, for barge cargo in Malaysia and Indonesia, the qualification must be determined through the selection of a crew with strict compliance with certification and laboratory cargo sample testing. For the carrier, before transportation, these responsibilities refer the duties and responsibilities of supercargo or the superintendent for matching or reconfirming the name of the charterer and the actual name of the IMSBC Code, as well as confirming the receipt of a third-party certificate of conformity rather than checking the appearance of the moisture content in the cargo. During the loading and transportation, if there were problems on the cargo, the captain at this time would be responsible for the supervision of the condition of the cargo.
For the transportation administrative authority, both the port administrative authority and the maritime administration play an important role in safety supervision. Taking China as an example, the regulations on the safety management of waterborne solid bulk cargo stipulate that the maritime administration is responsible for the safety supervision and management of the ship’s transportation of solid bulk cargo that may liquefy within its jurisdiction. However, the port administrative authority is responsible for the safety supervision and management of the loading, unloading, and storage of solid bulk cargo that may liquefy in the port under its jurisdiction. To ensure the safety of the carriers, the maritime administration has to extend the safety management requirements that the port, shipping agency, inspection agency, and other institutions must implement, resulting in the absence of the port administration and the overstepping of the maritime administration. Therefore, it is necessary to pay special attention to the coordination and management between the industry and government agencies and to clarify their logic and responsibilities. In particular, maritime administrations shall fulfil their responsibilities for maritime safety supervision and strictly control the navigation, ship management, crew management, risk prevention, and ship inspection management. They shall also define the duties of the captain and the crew to achieve the purpose of clarifying the division of responsibilities between them and the maritime administrative agency. Therefore, the division of responsibility should be clearer.
5.2. Due Diligence Operation of Seaworthiness in the Loading Process
To prevent ship sway and the endangerment of the safety of the hull structure, the cargo hold stowage plan should be properly developed following the specifications of the carrier. Both of the on-site verification of loading and the constant monitoring aim to keep the bulk carriers seaworthy for the bauxite shipping. In addition to carrying out corresponding self-inspections on general ship safety inspection items and bulk-carrier-exclusive safety inspection items, the following items should be listed in the self-inspection list according to the characteristics of solid bulk cargoes that may liquefy, including, but not limited to, bauxite:
The moisture content is kept below the transportable moisture limit.
The cargo working plan is effectively implemented.
Loading shall not be carried out during a period of precipitation unless otherwise specified.
The loading schedule and distribution of cargo is mastered to avoid excessive trim, roll, and overload.
During the loading, all hatches not in use are closed. After loading, the hatch is closed and covered and kept weather-tight.
Even loading must be kept to ensure the stability and seaworthiness of the carrier before sailing.
5.3. Properly Management of Cargo during the Shipping Process
5.3.1. Intelligent Monitoring of Cargo Liquefaction
Bulk carriers must install a water ingress alarm system in the cargo hold according to SOLAS 74-2002 Amended/CXII/R12. In addition to monitoring the water tightness of ballast tanks, the system also monitors the moisture released from the cargo to the bilge during navigation and starts the sewage well’s drainage device in time.
The alarm system can only detect the water level below 2 m and provide an early water level alarm. If the drainage is effective, the water level falls below the warning level, the risk of liquefaction is still under control for ship safety, and the alarm disappears within a short time. However, if the drainage is ineffective, the crew is unaware of the alarm or hears the alarm but did not respond, or the alarm system failed, the water level would rise over 2 m in more serious cases, and, at this time, the alarm system would be unable to provide further warning of liquefaction. After the liquefaction of bauxite or other cargo that may liquefy, moisture would shift from the bottom of the cargo hold to the upper space, and the low-height ingress alarm system would not be able to play an effective role. Additionally, it should be noted that the loading and unloading operations have a major risk of damaging the detection device, which could cause alarm failure or falsification.
The low reliability of the alarm system is detrimental to the seaworthiness of ships during the bauxite shipping process. Therefore, bauxite shall be under proper and prudent preservation, including the use of supplementary means to monitor the liquefaction state. The cargo hold’s liquid level detector is an effective means of supplementary monitoring. The detector is also known as a liquid level radar, and it can monitor the clearance height of the liquid level until the hatch cover in real time and then judge the water level height and measure the degree of cargo liquefaction. Another supplementary monitoring technology is laser scanning [
16] or image recognition, which can be used to regularly observe the surface morphology of the cargo before sailing and the cargo stack during the shipping process, thus, estimating the degree of liquefaction. This kind of liquefaction monitoring system was applied in a very large ore carrier (VLOC) to improve the safety of navigation. By monitoring the height of mineral precipitation in the cargo hold and the change in cargo heap form [
44], the liquefaction degree provides timely feedback to the crew to preprocess the problems of liquefaction, affecting the ship’s stability.
5.3.2. Prevention and Mitigation of Cargo Liquefaction
Intelligent monitoring may be inaccurate in a few cases. At such a time, the crew on duty should be sent to determine a judgment by observing the cargo based on their experience. At this time, the inspection crew must be required to have a certain level of ability. However, in special circumstances, in order to protect the safety of the life of the crew, the cargo cannot be manually checked. In addition, if the monitoring device detects any danger, an alarm sounds. However, once the officer on duty is unaware of the danger, the accident may still occur if the correct measures are not taken in time due to stress, assumptions, or a lack of knowledge, perhaps because of the influence of the surrounding environment or personal reasons, or even if the danger is perceived. Therefore, not only should an intelligent monitoring system of liquefaction be implemented, but also the subsequent intervention of cargo liquefaction. It is generally considered that the period within 10 h after departure is a dangerous period for the cargo stack. The master can use reliable measures to delay and prevent the liquefaction of the cargo. If a lower moisture content than the TML, the opening of the hatch cover, ventilation and airing, sampling, and inspection should be performed in the anchorage to avoid the dangerous situation of cargo liquefaction in the early days of the sailing process [
45].
5.3.3. Emergency Drill for Cargo Liquefaction
The use of extreme caution to mitigate these risks should be further supplemented with improvement measures and a full awareness of the hazards to the seafarer and ship caused by transporting liquefied solid cargo in bulk carriers. These steps must be taken to establish an emergency response plan for cargo liquefaction and to carry out regular emergency drills for the maritime transportation of cargoes that may liquefy, including systematic response measures for moisture shifting, particle movement, cargo heap deformation, and the degree of liquefaction. In particular, crews should become familiar with the regularity of variations in the ship’s attitude motion from large-angle rolling to capsizing and sinking due to the serious liquefaction of cargo. A scientific and accurate judgment should be determined on the dangerous situation and the abandonment of the ship would need to be announced at the right moment. Based on the angles of the heel and the angle of the trim owing to cargo liquefaction before the declaration of the abandonment order, it is beneficial to learn from the method of determination of the stability parameters and the position of the ship during the flooding of the cargo hold [
46].
If there is a short time from the awareness of the great danger to the sudden capsizing of the ship, the crew cannot take any measures to save the ship and cannot even abandon the ship effectively, resulting in a major loss of the ship and crew. To avoid the danger caused by the immediate capsizing of the ship, or the sudden large-angle heeling from one side to the other without immediate capsizing, the ship should be abandoned decisively when the loss of the ship is inevitable, to ensure a rapid, safe, and orderly evacuation and reduce casualties. The effectiveness of the abandonment depends on the continuous monitoring of liquefaction, the ability to detect early danger and sounding the alarm, the ability to judge the residual stability of the ship, and the decision making to abandon ship.
6. Conclusions
The paper critically examined the seaworthiness of bauxite bulk carriers under the 2019 amendments of the IMSBC Code, which had a significant commercial effect of improving productivity and efficiency. This was accomplished by increasing and giving a legal backbone to the standards of due diligence and eventually decreasing the chances of unseaworthy Handy carriers with liquefaction being sent to the sea, as well as reducing the risk of maritime incidents on ships and cargo, and, most importantly, preventing the loss of seafarers on board. Through the discussion of the concept of seaworthiness in maritime technology in terms of the different aspects of ship construction, equipment, and cargo stowage, as well as an analysis of the development of the doctrine of seaworthiness in maritime law, especially the relationship between seaworthiness and cargo worthiness, cargo transportability, the preservation of cargo, and external supervision based on the scope of application of seaworthiness, it was found that PSC inspections, ship surveying, and ship endorsement are the keys to the external guarantee of ship seaworthiness. Additionally, the paper then explored the implications of introducing the doctrine of seaworthiness in the 2019 amendments of the IMSBC Code based on a correlation analysis between the ship operation and ship seaworthiness based on bauxite liquefaction characteristics.
The paper found that it is crucial for the ship to remain seaworthy throughout the whole logistics chain of bauxite for the safety of life, the ship, and the marine environment. The due diligence operation of seaworthiness in the loading process and the proper management of cargo during the shipping process can keep the ship seaworthy. This paper provided some suggestions to ensure the seaworthiness of bauxite carriers, which involves ensuring cargo worthiness, cargo transportability, and competency for the seafarer. The intelligent monitoring of cargo liquefaction, the prevention and mitigation of cargo liquefaction, and emergency drills for cargo liquefaction are recommended measures to keep seaworthiness during the shipping process. These prudent practices are of great significance for preventing accidents and clarifying legal liability once there is a civil dispute related to the contract and the careful placement of cargoes to ensure the safety of the ship.
It should be noted that some regrets appeared in the interpretation of seaworthiness. The IMO, the IMSBC, Charter Party, and Marine Insurance legal terms vary in meaning or expression depending on the context, so when applying related laws and regulations to specific cases, the law should be interpreted correctly. Even if the terms and phrases used in the two related laws were the same, the meaning may be different, or the same meaning may be used with different terms, so if the law is not properly interpreted in its application to specific issues, which may cause errors. Interpreting the law is based on and begins with literary interpretation. Literary interpretation is “an interpretation that focuses on the text and terms of the law and has a general meaning of the article”. “Interpretation of the law” is a theoretical and technical action that clarifies the concept of norms. It is necessary to adopt appropriate theories and methods to clarify the connotations and differences in the application of different terms.
The authors tried to interpret the definition of seaworthiness in detail, but were limited by the applicable legal environment and the ship operation scene. This paper focused on discussing the technical connotation of seaworthiness under the framework of the IMSBC, so it did not carry out an excessively detailed identification in judicial aspects. A comparative study should be conducted on this insurance issue raised by the reviewers in another paper. In this regard, this paper still needed further theoretical and applied research combined with legal practice. Beyond that, it examined the relationship between ship seaworthiness and cargo custody in the ore port yard, to further widen and deepen the basic idea of seaworthiness in terms of the orientation of the value of safety.