Ballast Water Tanks Research Articles

EIS offset-cell measurements on epoxy-based coating systems over mechanically and thermally rounded cut edges

Based on electrochemical impedance spectroscopy (EIS) measurements with a specially designed offset-cell, the protection performance of epoxy-based coatings in terms of coating resistance over cut edges was investigated. The edges were rounded with different mechanical and thermal tools, including CO2-laser, solid-state laser, plasma beam, grinding and milling tools. Two coating systems for ballast water tank environments and two rounding radii were considered. The samples were investigated by means of a specially designed EIS offset-cell suited for applications to edge geometries. The target parameter for the assessment of the protection performance of the coatings was a critical exposure time for RC < 106 Ω, whereby RC is the coating resistance. The critical exposure time could be linked to various coating defects, namely to blistering. Results of statistical investigations revealed statistically insignificant effects of the edge rounding radius.

Autonomous GPU-based UAS for inspection of confined spaces: Application to marine vessel classification

Inspection of confined spaces poses a series of health risks to human surveyors, and therefore a need for robotic solutions arises. In this paper, we design and demonstrate a real-time system for collecting 3D structural and visual data from a series of inspection points within a prior map of a confined space. The system consists of a GPU accelerated 3D point cloud registration and a visual inertial odometry estimate fused in an Unscented Kalman Filter. Using the state-of-the-art deep learning-based feature descriptors, FCGF –and the robust Teaser++ 3D registration algorithm– point clouds from a narrow field of view, time-of-flight, camera can be registered to a prior map of the environment, to provide accurate cm-level absolute pose estimates. The uncertainty of the system is furthermore estimated on the basis of the novel GPU-based Stein ICP algorithm. Visual defects, represented by augmented reality fiducial markers, are automatically detected during inspection, and their positions are estimated in the map frame of the confined space. The performance of the system has been evaluated in realtime onboard a small UAV, within a mock-up model of a water ballast tank from a marine vessel, where the UAV was able to navigate and inspect the ambiguous and featureless environment. All defects were estimated within ＋/−10 cm of their actual position.

The Crab at the End of the World

The Chinese Mitten Crab, a freshwater crab species originating from China, was accidentally introduced in Europe in the early 20th century when Western steamers, returning from China, emptied their ballast water tanks in German harbours. From there, in the course of the last century, the species gradually colonized the coastlines of the North Sea and the Atlantic southwards, but also much of the rest of the world. This visual essay is based upon material collected by Rotor for an installation at the 2018 Bruges Triennial. The narrative starts form the massive but scarcely known presence of the crab in the world-famed canals of the city of Bruges to tell the story of the species' amazing resilience and age-old adaptedness to anthropogenic environments. This is also a reconstruction of the Mitten Crab's unique travel patterns, partly the result of the species own migratory drive, but partly also following, unwittingly, the tendency of humans to travel ever further, ever faster. Like the exhibition, the essay explores the habits and motivations of an invasive species while deliberately suspending judgment. This is not to excuse the species of harming local biodiversity. But to recognize the fair share of responsibility we as humans bear in the present situation.&amp;nbsp;

Root causes for corrosion on painted steel structures in marine environments

AbstractOur understanding of the failure mechanisms of coatings, for example, cathodic disbonding, corrosion creep, blistering, and cracking, have been developed to a high level over the past decades. However, knowing what actually causes coatings to fail in the field is also important. Several atmospheric field tests of coating with duration 2–9 years have been published, showing that epoxy‐based heavy‐duty protective coating systems with zinc‐rich primers have high resistance against corrosion creep from damages in the coating. Despite this, scribe creep corrosion has become the most important evaluation parameter in standardized testing. In this work, inspection pictures from an offshore oil and gas platform, a ballast water tank system, and two coastal road bridges have been analyzed with respect to the root cause for initiation of corrosion on coated steel. The results show that corrosion mainly initiates at edges and welds. Between 50% and 90% of the corrosion attacks could be attributed to this, depending on the type of structure. The paint failed due to low film thickness, that is, the wet paint retracts from sharp edges in the surface so that the cured film has reduced barrier properties.

The dispersal of dinoflagellate cyst caused by international ships under repair conditions: a potential invasion risk to the Yangtze River Estuary, China.

The foreign dinoflagellate cysts in ships' ballast water tank sediments (BWTS) can be viable for a long time under hostile storage conditions. It is crucial to understand the detailed mechanisms of harmful biological invasions in estuary ecosystems. To study the relationship between the abundance of dinoflagellate cysts and environmental factors, cyst assemblages were analyzed in 7 sediment samples, collected from one international commercial ship that arrived in Shanghai in August 2020. Twenty-three dinoflagellate cyst taxa were identified in 5 groups, including autotrophic (9) and heterotrophic (14) species. Distribution of dinoflagellate cysts in the different ballast water tanks is heterogeneous. Dinoflagellate cysts in BWTS of the repaired ship were dominated by Scrippsiella acuminata, Protoperidinium leonis, Protoperidinium oblongum, Lingulodinium polyedra, Alexandrium tamarense/A. catenella, Protoperidinium pentagonum, and Protoperidinium subinerme. The abundance of the dinoflagellate cysts in each tank ranged from 80.69 to 330.85 cysts g-1 DS (dry sediment). Multivariate statistical analyses revealed that the variation in cysts from different tanks had positive correlations with total nitrogen (TN), total phosphorus (TP), and pH and negative correlations with total organic carbon (TOC) except for sample TK5. For germination of dinoflagellate cysts in BWTS, 12 species were germinated in 40days and cysts of potentially toxic dinoflagellate species were more abundant than those of non-toxic species. Results show that potentially viable and harmful/toxic dinoflagellate cysts are present in BWTS of ships arriving in Shanghai, China. Consequently, knowledge obtained in this study can be valuable for further managing of potential biological invasion of the Yangtze River Estuary.

Evaluation of the Corrosion Depth of Double Bottom Longitudinal Girder on Aging Bulk Carriers

The longitudinal girder (LG) between fuel oil tanks (FOT) and water ballast tanks in the double bottoms of ships represent critical structural parts whose watertight nature could be harmed by corrosion, thus, causing the pollution of water ballast tanks and adjacent areas. The new common structural rules (CSR) define the minimum thickness values of structural elements and corrosion margins. The assessment of the deviations from the prescribed values during ship operation could optimize the prescribed criteria. Assuming that corrosive processes begin after four years of operation, the paper analyzes a linear model that describes the percentage of plate wear as a function of the built-in thickness of LG of FOT. The research included 20 ships and provided the database for 1918 corrosion depth values. The gauging records included the average values of the original thickness of steel plates grouped in three intervals (11–13 mm, 13–15 mm, 15–18 mm). Based on the difference between the built-in and subsequently measured values, the paper analyzes the percentage of thickness reduction due to corrosion, concerning the original plate thickness. The findings of the research should facilitate the optimization of corrosion margins and prevent potential structural collapse and pollution.

Investigation of Q235 low-carbon steel corrosion under simulated ballast water tank conditions

Investigation of Q235 low-carbon steel corrosion under simulated ballast water tank conditions

Two-phase Flow Analysis for Small-scale Ballast Water Tank Model by Hydraulics Experiment and Simulations

This study is utilizing hydraulics experimental and computational fluid dynamics (CFD) methods to verify the flow phenomenon in the ballast water drainage process and discuss the drainage efficiency. In order to facilitate the analysis of the flow characteristics of ballast water in the ballast tank of a typical bulk carrier, the complex structure is simplified into two simple small-scale models, a single-longitudinal model and a single-transversal model. Both are designed with the scale of 1:10 for the data collection. The experimental results are then validated and verified by conducting a two-phase flow model applied volume of fluid (VOF) method. Based on that result, the use of the VOF method is suitable for the ballast water drainage simulation, so it can be used in large-scale model calculations to predict the drainage efficiency of ballast tanks. In addition, this study also conducts a comparative analysis of two configuration modes of the single-longitudinal model and the single-transversal model, which provides a reference for the design and improvement of complex structures.

The degradation mechanism of a marine coating under service conditions of water ballast tank

An epoxy amine-based seawater ballast tank coating was characterized after 18 years of exposure to service environment. Coating flake specimens were taken from a flat region of the ballast tank, which appeared intact and well attached to the steel substrate. The flakes were examined using analytical electron microscopy and Fourier transform infrared (FTIR) spectroscopy. Significant morphological changes in the pigments and binder in the near surface region were observed. These were related to the hygrothermal cycles due to filling and discharge of sea water in the ballast tank, accompanied by cyclic temperature variations, generating expansion and contraction stresses within the coating. The analyses also reveal for the first time differences in the damage to barrier pigments (i.e. talc and kaolin) compared to the degradation of aluminium flake metal pigment. The former were fractured internally while the latter showed failure at the pigment/binder interface. Since pigments play a significant role on the degradation of the coating, their orientation towards the surface was also found to be of high importance. Regions of coating with pigments orientated nearly vertically to the surface showed a more severe degradation than regions with pigments orientated nearly parallel to the surface.

Using Onboard-Produced Drinking Water to Achieve Ballast-Free Management

Based on the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (the Ballast Water Management Convention, or BWM Convention) of the International Maritime Organization, from 8 September 2017, all ships must have an approved Ballast Water Management Treatment System (BWTS) to prevent the invasion of alien species through the discharge of ballast. Generally speaking, the need for an approved BWTS is limited to large vessels, as they are too large or too expensive for small vessels to install. This study aims to propose a simple ballast-free approach for small vessels (e.g., tugs, workboats, research vessels) that require ballast to compensate for the weight loss of fuel when sailing. Our approach involves refitting the dedicated ballast tank of these small vessels to be drinking water tanks and filling the tanks with onboard-generated distilled or reverse osmosis water to adjust the stability of the ships. We assessed our approach using three vessels. Two ships using our proposed method were certified by the American Bureau of Shipping as containing no ballast water tank, and not being subject to the BWM Convention. This study provides an environmentally harmless, easy to use, and economical approach for small vessels to comply with the BWM Convention.

H2O2-assisted photocatalysis induced by SPR of BiQDs anchored on BiVO4 for the production of hydroxyl radicals in seawater

Ballast water is an essential component of nautical navigation, however, the microorganisms present in the water may be an environmental hazard. Therefore, the decontamination of ballast water has been widely studied. The anchoring of metal nanoparticles with plasmonic properties into semiconductors is an effective way to enhance their photocatalytic activity for the inactivation of marine microorganisms in ballast water. In this paper, we describe the successful synthesis of BiQDs/BiVO4 via a facile solvothermal method and evaluated their capacity to inactivate marine microorganisms under visible light irradiation. The results showed that 3%BiQDs/BiVO4 exhibited greatest photocatalytic sterilization efficiency with the low concentration of H2O2 present in real seawater. Further results revealed that the BiQDs had a diameter of approximately 5.1 nm and were distributed randomly on BiVO4, and that the SPR effect of BiQDs enhanced the utilization of visible light. The hydroxyl radical was proven to be the main active species and the addition of H2O2 promoted the generation of ·OH to achieve the efficient decontamination of ballast water. This study may provide a potential route for the photocatalytic removal of marine microorganisms and ballast water tank protection.

Investigating the Motions Behavior of a Ferry in Waves Caused by Damaged Conditions

A progressive flooding-ingress of water to a compartment of a damaged ship affects the motions of a ship. In this present study, the behavior of the motion of a ferry caused by damaged conditions in waves was investigated through the experimental work. The leakage of compartments was made into several scenarios including one, two, and three damaged compartments, and the damaged ship model was simulated in heading and beam waves. The research results show the one damaged compartment on the engine room (ER) affected extreme stern trim as well as Void No.1 affected extreme bow trim. The two damaged compartments on the water ballast tank (WBT) No.2 and Steering gear room (SGR) resulted in extreme stern trim as well as WBT No.1 and Void No.1 affected extreme bow trim. The heave, pitch, and roll responses on the damaged Void No.1 are higher comparing with the damaged ER. Also, the heave, pitch, and roll responses on damaged SGR and WTB No.2 are higher than Void No.1 and WBT No.1. The peak resonances of heave RAO on bow trim affect higher magnitude than on stern trim. Pitch or roll RAO caused by the increased bow trim or stern trim in head and beam waves has a small magnitude within the response.

JIP Drives New Ways of Managing Integrity of Floating Oil and Gas Assets

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper OTC 30425, “Innovative Asset-Integrity Management To Drive Operational Effectiveness,” by Danny Constantinis and Peter Davies, EM&amp;I, prepared for the 2020 Offshore Technology Conference Asia, originally scheduled to be held in Kuala Lumpur, Malaysia, 17–19 August. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. While the focus on the growing floating gas industry is firmly on output, the industry needs to ensure safety, compliance, and profitability of high-value, complex, floating gas assets, some of which operate close to high population densities. Effective asset-integrity programs are a key part of such an effort, and it is widely agreed that better use of data and robotics will help reduce unnecessary work and human risk. The complete paper describes a joint industry approach for addressing asset-integrity management challenges that has proved successful for floating production, storage, and offloading vessels (FPSOs). Introduction Managing the integrity of offshore, near-shore, and berthed floating oil and gas assets faces numerous challenges, including the following: - Long service lives - The need to cut operating costs - Varying asset-integrity requirements of marine and process equipment - Growing global demand for gas - Increasing requirement to drive down carbon emissions - The need for enhanced sustainability Traditional cost-reduction strategies of prior lean market periods are no longer accepted by the industry, which the authors say needs to implement permanent cost reductions, increased sustainability and efficiency, and improved safety. These can be achieved only by new ways of managing asset integrity, targeted at consistent low price and efficiencies and developed, supported, and accepted by all sectors of the industry. Role of the Joint Industry Project (JIP) The Hull Inspection Techniques and Strategy (HITS) JIP has encouraged such innovations. The complete paper describes new methods facilitated by HITS that include diverless inspections of hulls and mooring systems and remote, unmanned methods of inspecting confined spaces such as cargo and water ballast tanks. Organizations such as the HITS JIP, whose membership includes oil majors, service providers, classification societies, and regulators, and the FPSO Research Forum, of which HITS is a part, have helped define the direction for improvements in inspecting, maintaining, and repairing floating production assets. These organizations have encouraged the development of new technologies that have improved safety and reduced operational costs. According to the paper’s authors, this direction has also shaped the drilling sector, can do the same for floating liquified natural gas (FLNG) and floating storage and regasification units (FSRU), and could potentially expand into floating renewable-energy-production assets. These and similar concepts are now being taken forward in a floating gas (FloGas) JIP.

Sample size for estimating organism concentration in ballast water: A Bayesian approach

Estimation of microorganism concentration in ballast water tanks is important to evaluate and possibly to prevent the introduction of invasive species in stable ecosystems. For such purpose, the number of organisms in ballast water aliquots must be counted and used to estimate their concentration with some precision requirement. Poisson and negative binomial models have been employed to describe the organism distribution in the tank, but determination of sample sizes required to generate estimates with pre-specified precision is still not well established. A Bayesian approach is a flexible alternative to accommodate adequate models that account for the heterogeneous distribution of the organisms and may provide a sequential way of enhancing the estimation procedure by updating the prior distribution along the ballast water discharging process. We adopt such an approach to compute sample sizes required to construct credible intervals obtained via two optimality criteria that have not been employed in this context. Such intervals may be used in the decision with respect to compliance with the D-2 standard of the Ballast Water Management Convention. We also conduct a simulation study to verify whether the credible intervals obtained with the proposed sample sizes satisfy the precision criteria.

Uncovered pathways: Modelling dispersal dynamics of ship‐mediated marine introduced species

Abstract Marine traffic is the main vector for marine non‐indigenous species (NIS) that may hitchhike in ballast water tanks or attached to vessel hulls. Understanding marine traffic dynamics and estimating the associated risk of NIS dispersal reveals points of leverage for preventive NIS management. This study presents a method to quantify the risk of ship hull fouling‐mediated NIS dispersal and identifies main dispersal hubs in marine traffic networks. We use the Galapagos Marine Reserve (GMR) as a case study to test the applicability of this method. Ship position data derived from the automatic identification system (AIS) served as a basis for a network consisting of nodes (moorings and anchorages) and edges (ship routes). Wetted surface areas (WSA) describe the parts of vessel hulls submerged by water and were used to parameterize dispersal risks of individual vessels. We combined the constructed network with a numeric dispersal model and sequentially removed network elements to test their effectiveness on decreasing the overall dispersal capacity. Marine traffic hotspots, such as ports and popular marine visitor sites, represented the main dispersal hubs and incoming edges into the GMR crucial links for the overall dispersal capacity. The removal of passenger vessels had the strongest effect on the overall dispersal capacity, reducing it to 1%. Based on our findings, we suggest management recommendations to curb the spread of marine NIS in the GMR, including the implementations of (a) vessel hull controls at main dispersal hubs (ports); (b) species monitoring programmes at popular marine visitor sites and (c) hull husbandry regulations for passenger vessels. Synthesis and application. In an increasingly connected world, the development of risk assessments for marine non‐indigenous species (NIS) dispersal is a crucial step towards the sustainable use and protection of marine ecosystems in Galapagos and other places. The presented methodology is solely based on the pathway component and thus applicable to any place with available ship position data. Therefore, it may provide useful baseline information for preventive measurements especially in places where ecological data about NIS are scarce.

Simulation of emergency hovering maneuvers in submarines

Submarines are one of the most advanced marine vehicles navigating from the surface of the water to the depths of the seas and able to perform various operations. Submarines have no benefit in terms of speed relative to surface floats, but also the advantage of a (moving underwater) dive deep into the deep seas. Diving and hovering of a submarine are carried out with the help of water ballast tanks (WBTs). Considering the importance of WBTs in the dynamic and static stability of the submarine, in examining the emergency maneuver operations using WBTs, complete modeling of the compressed air blowing process in the main WBTs of a submarine should be made. Blowing and unloading submarine ballasts can potentially use as a complementary control system to improve submarine maneuverability. Submarine ballast tanks can use as a tool for emergency hovering operation. This critical issue has simulated in this article using StarCCM + software, among which the governing equations and essential parameters have been investigated. Also, a sensitivity analysis was done on the results.

Sloshing effect, Fluid Structure Interaction analysis

The sloshing effect of the liquids is considered to be an important factor in area such as cargo ships (tankers) which transporting petroleum liquids or other liquids (water inside of ballast tanks). Sloshing can produce big problems so is essential to apply the prevention measures. For example in water ballast tanks, the sloshing motion of sea water inside of ballast tanks will bring large fluid pressures and impact loads, which might destroy the structure of tanks. It is known that ships with larger tanks, less internal structure, and more free surface area, the number of failures attributed to sloshing liquids have increased. Nowadays it is recognized that the ballast tanks which may be partly filled are the crucial group of tanks onboard. The problem of an assessment of liquid sloshing effect is more important than ever because of the obligatory ballast water management requirement. Our paper is an original fluid structure interaction analysis during sloshing phenomenon. We are using ANSYS CFX to simulate the behavior of two fluids, (seawater and air from the ballast tank), requires itself the multiphase flow model. Due to the movement of the ballast/cargo tanks is complex involving pitching and rolling of ship, it is clear that the simulation is done with the ANSYS CFX transient module. Because this complex simulation requires massive resources calculation we consider a simplified CAD models for a part of the oil chemical ballast tank structure.

Changes in the ballast water tank bacterial community during a trans-sea voyage: Elucidation through next generation DNA sequencing

Ballast water (BW) mediated bioinvasion is one of the greatest threats to the health of aquatic ecosystems. Bacteria, unlike higher organisms, are transferred in large numbers through BW. Owing to their abundance and potential pathogenicity, they pose a direct threat to the prevailing microbiome in the recipient waters and also to human health. This study investigated the changes in the BW tank bacterial community during a trans-sea voyage from Visakhapatnam port, located along the east coast of India (Bay of Bengal) to Mumbai port, located along the west coast of India (Arabian Sea). Next generation sequencing was used to explore the unculturable segment of bacteria. The BW tank conditions led to a decrease in photoautotrophs and non-spore forming bacteria. On the other hand, biofilm forming and antibiotic producing bacteria, nutrient limiting condition sustaining bacteria, and those capable of synthesizing enzymes prerequisite for active metabolism under stress, increased over time. The shifts in the bacterial community were dependent on mechanisms adopted by the clades to cope with the BW tank conditions. Functional prediction of the bacterial community revealed a significant increase in the core metabolic functions, which enabled the survival of such bacteria. As the voyage progressed, an increase in the total viable bacteria in BW tanks could be attributed to the decrease in the abundance of phytoplankton and zooplankton. At the end of the voyage, the bacterial community in the BW tanks was significantly different, and the species diversity and richness were higher than that of the natural seawater (source water). Pathogenic species were more abundant during mid-voyage than at the end of the voyage, suggesting that voyage duration influences the pathogenic bacterial community. Investigating the fate of the discharged bacterial population at the deballasting point is a way forward in the assessment of marine bioinvasion.

Metabarcoding quantifies differences in accumulation of ballast water borne biodiversity among three port systems in the United States

Characterizing biodiversity conveyed in ships' ballast water (BW), a global driver of biological invasions, is critically important for understanding risks posed by this key vector and establishing baselines to evaluate changes associated with BW management. Here we employ high throughput sequence (HTS) metabarcoding of the 18S small subunit rRNA to test for and quantify differences in the accumulation of BW-borne biodiversity among three distinct recipient port systems in the United States. These systems were located on three different coasts (Pacific, Gulf, and Atlantic) and chosen to reflect distinct trade patterns and source port biogeography. Extensive sampling of BW tanks (n = 116) allowed detailed exploration of molecular diversity accumulation. Our results indicate that saturation of introduced zooplankton diversity may be achieved quickly, with fewer than 25 tanks needed to achieve 95% of the total extrapolated diversity, if source biogeography is relatively limited. However, as predicted, port systems with much broader source geographies require more extensive sampling to estimate diversity, which continues to accumulate after sampling >100 discharges. The ability to identify BW sources using molecular indicators was also found to depend on the breadth of source biogeography and the extent to which sources had been sampled. These findings have implications both for the effort required to fully understand introduced diversity and for projecting risks associated with future changes to maritime traffic that may increase source biogeography for many recipient ports. Our data also suggest that molecular diversity may not decline significantly with BW age, indicating either that some organisms survive longer than recognized in previous studies or that nucleic acids from dead organisms persist in BW tanks. We present evidence for detection of potentially invasive species in arriving BW but discuss important caveats that preclude strong inferences regarding the presence of living representatives of these species in BW tanks.

Historical human activities reshape evolutionary trajectories across both native and introduced ranges.

The same vectors that introduce species to new ranges could move them among native populations, but how human‐mediated dispersal impacts native ranges has been difficult to address because human‐mediated dispersal and natural dispersal can simultaneously shape patterns of gene flow. Here, we disentangle human‐mediated dispersal from natural dispersal by exploiting a system where the primary vector was once extensive but has since ceased. From 10th to 19th Centuries, ships in the North Atlantic exchanged sediments dredged from the intertidal for ballast, which ended when seawater ballast tanks were adopted. We investigate genetic patterns from RADseq‐derived SNPs in the amphipod Corophium volutator (n = 121; 4,870 SNPs) and the annelid Hediste diversicolor (n = 78; 3,820 SNPs), which were introduced from Europe to North America, have limited natural dispersal capabilities, are abundant in intertidal sediments, but not commonly found in modern water ballast tanks. We detect similar levels of genetic subdivision among introduced North American populations and among native European populations. Phylogenetic networks and clustering analyses reveal population structure between sites, a high degree of phylogenetic reticulation within ranges, and phylogenetic splits between European and North American populations. These patterns are inconsistent with phylogeographic structure expected to arise from natural dispersal alone, suggesting human activity eroded ancestral phylogeographic structure between native populations, but was insufficient to overcome divergent processes between naturalized populations and their sources. Our results suggest human activity may alter species' evolutionary trajectories on a broad geographic scale via regional homogenization and global diversification, in some cases precluding historical inference from genetic data.