Vessel Hull Research Articles

Zoobotryon verticillatum (Bryozoa: Ctenostomatida: Vesiculariidae), a new occurrence on the Mediterranean coast of Israel

Zoobotryon verticillatum, a widely dispersed stoloniferous fouling bryozoan, has been recently recorded from specimens collected from the hulls of vessels berthed in an Israeli marina. Though conspicuous and distinctive, it has been rarely recorded in surveys of the bryozoan fauna along the Levant coastline conducted over the past half century. It is suggested the species is native to the Caribbean Sea, and an invasive alien elsewhere, including the Mediterranean Sea.

Erratum

Diversity and DistributionsVolume 19, Issue 12 p. 1578-1579 ErratumOpen Access Erratum This article corrects the following: Is vessel hull fouling an invasion threat to the Great Lakes? Francisco Sylvester, Hugh J. MacIsaac, Volume 16Issue 1Diversity and Distributions pages: 132-143 First Published online: November 30, 2009 First published: 07 November 2013 https://doi.org/10.1111/ddi.12141AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL In Sylvester and MacIsaac (2010), the wrong taxa abundance dataset was used for richness estimations. While some figures and models were recalculated for data accuracy, all overall findings of the paper remain the same. The correct abundance dataset has been posted in the Appendix S1 and S2 files. The correct form of Equation (2) is: R = 0.3501TP – 1; with AICc = 169.95. The following figures have been recalculated: Figure 3Open in figure viewerPowerPoint Chao-2 species richness estimate for ships in this study. Estimate values could not be calculated for four ships due to lack of duplicates. Error bars indicate 95% confidence intervals. Values off the scale are indicated. Figure 4Open in figure viewerPowerPoint Individual-based rarefaction curves for all ships pooled from this study (dark line ± 95% C.I.) and the ship sampled by Drake and Lodge [2007; grey line (± 95% C.I.)]. Also shown are Chao-1 species richness estimates (± 95% C.I.) for our study and that of Drake and Lodge. Species richness estimates for our study either excluded species found in Great Lakes' port water (open bar) or included them (solid bar), whereas Drake and Lodge's estimate includes these species (grey bar). Chao-2 richness estimates for our study were 148 and 164 species without and with port water samples considered, respectively. Figure 5Open in figure viewerPowerPoint Individual-based rarefaction curves for underwater locations with significantly different asymptotic richness (a), Chao-2 species richness estimate (b), and average percentage cover (c) for all locations across all ships in this study. Dotted lines and error bars indicate 95% confidence intervals. Values off the scale are indicated. Sea chest refers to the protective grating covering its exterior surface. Figure 6Open in figure viewerPowerPoint Principal component analysis of invertebrate communities fouled on hulls of vessels sampled in the Great Lakes based on ports visited over the year prior to sampling. Geographical identities represent total (black open symbols) and maximum (black solid symbols) residence time of vessels in port in that region over the preceding year. Variables related to fouling extent are indicated with grey crosses. Other variables are indicated with grey triangles. Last painted and last dry-dock refer to times since application of an antifouling agent and since the vessel was removed from the water for maintenance; speed refers to the vessels' reported cruising speed; % cover barnacles refers to total percentage cover of barnacles on the ship. Percentage of the total variance explained along the first and second PCA axes is indicated. Reference Sylvester, F. & MacIsaac, H.J. (2010) Is vessel hull fouling an invasion threat to the Great Lakes? Diversity and Distributions, 16, 132– 143. Volume19, Issue12December 2013Pages 1578-1579 FiguresReferencesRelatedInformation

Resistance and Strength Analysis of Three Hulls with Different Knuckles

Three FRP fishing vessel hulls with different knuckles, the two knuckles ship, the round bilge ship and the single knuckle ship (hereinafter using abbreviation the TKS, the RBS, and the SKS, respectively), are studied to reduce resistance and enhance strength. Here the TKS is a variation design from the RBS. And the knuckles on the hull were designed paralleled with the streamlines of the hull surface of the RBS at the design speed, and the SKS is applied as the comparison ship. The resistance of the three hulls is predicted using the CFD software FLOW-3D, at the same time, the midship section modulus of the three hulls is calculated in this paper. It shows that the resistance of the TKS is slightly lower than that of the RBS at the design speed, and about 50% lower than that of the SKS. On the other side, the strength of the TKS increased about 15% than the RBS, and 6.9% than the SKS.

Statistical characteristics of acoustic signals reflected from maritime vessels during contintuous emission

The paper presents the results of experimental studies of fluctuations in echo signals from maritime vessels under conditions of near echo ranging with continuous targeted emission and reception at a frequency of 80 kHz. Data have been obtained on the fluctuation intensity, distribution functions, spectra, and time coherency fluctuations of echo signals at various vessel velocities for different reflecting and scattering areas of vessel hulls, different areas of the scattering layer of air bubbles formed at the hull of a moving vessel, and the cloud of air bubbles remaining behind the stern after a vessel has passed.

The Optimization Design of the Planing Vessel's Channel Parameters Based on the CFD Technology

Due to the special hull shape of the catamaran planing vessel, the shiplines optimization design and the hydrodynamic performance prediction of the catamaran planing vessel are mainly carried out by model tank tests and the empirical formula at present. The numerical prediction method of the hydrodynamic performance of catamaran planing vessel has been a big difficulty for a long time. In this paper, the influence of the key channel design parameters on the catamaran planing vessel hydrodynamic performance is studied based on the CFD technology. Some beneficial conclusions are obtained which is helpful for the optimization design of catamaran planing vessel. The work of this paper provides a numerical research method for the optimization design of the catamaran planing vessels hull.

Numerical Prediction Method of Resistance Performance of Catamaran Planing Vessels

The classical approaches using CFD software to calculate the hydrodynamic performance of catamaran planing vessel still need to rely on the model test or empirical formula to make sure of the running attitude. So a theoretical calculate method of resistance performance of catamaran planing vessel is proposed in this paper based on RANS equations and the VOF method to couple six degrees of freedom equation of the catamaran planing vessel. Numerical simulation results indicate that using RANS equations can better forecast hydrodynamic performance of catamaran planing vessel at high speed, which provides a practicable numerical method for optimization design of the catamaran planing vessels hull.

Diagnosing Propulsion Systems of a Vessels in Varying Marine Conditions

The paper presents some problems of carrying out measurements of energetic characteristics and vessels performance in the conditions of sea examinations. We present the influence of external conditions in the change of vessels hull resistance and propeller characteristics as well as the influence of weather conditions in the results of examinations and characteristics of gas turbine engine. We also discuss the manner of reducing the results of measurements to the standard conditions. We present the way of preparing propulsion characteristics and the analysis of examination uncertainty for the measurement of torque.

Failure analysis of fuel tanks of a lightweight ship

This manuscript describes a failure analysis carried out in fuel tanks of a lightweight ship that was designed to operate not far from shore.The ship under study is a high speed light craft that was entirely designed and manufactured in Portugal and has been successfully operating as a patrol boat for several years. The vessel under study was manufactured with two types of naval aluminium series alloys, namely the 5083-H111 and the 6082-T6 alloys, which are commonly used in shipbuilding. The former alloy can be strain hardened by cold work and is used in the form of rolled plates and sheets for the vessel hull, the superstructure, and the bulkheads. The 6082-T6 alloy is a high-strength alloy that can be heat treated and softens near the heat affected zone during welding. It is used in the high-stressed structural members of the ship, namely in the stiffeners of the reinforced panels.The two fuel tanks under study are located at the rear of the ship, one at the starboard and the other at the portside. Cracks have propagated from the weld toe of some T-welded joints that possess low fatigue strength resistance. The welded joints were made using TIG and MIG processes and the weld quality was assessed by visual inspection, dye penetrant examination and radiography.The fuel tank’s failure due to exfoliation, hot cracking, stress corrosion cracking or fatigue are analysed in the paper and it was concluded that fatigue is the most probable cause of failure. In addition, the 3D modelling of the current fuel tank geometry and its analysis by the finite element method (FEM) allowed the behaviour of the structure to be studied and it was discovered that the highest stressed regions were located at the reinforcement stiffeners where cracks nucleated and propagated.As a result, several alternative geometries for the fuel tanks were simulated in a FE computer code and it was possible to reduce the overall maximum stresses applied in the structure in the order of 65% with an increase of 20kg per fuel tank to the total weight of the vessel.

An innovative method for parametric design of planing tunnel vessel Hull form

In this work, a new mathematical procedure has been developed to automatically generate the hull form of planing tunnel vessels. Due to the complex and time consuming nature of the hull form generation, it is vital to use a nimble and precise method in designing and optimization of hull form of these vessels. In the present method, the minimum number of input control parameters has been employed to design the hull form geometry. In the first step of modeling procedure, four longitudinal guideline functions are defined that use two different approaches, namely, polynomial functions and Non-Uniform Rational B-Spline (NURBS) curves. In the second step, using specified key points, the section curves are generated via three different models including; the parabolic, the elliptic and the NURBS curves. Then, the fair transverse sections, the fair surfaces and the solid models could be generated. In a case study, the generation of a number of hull forms based on three different models, implies that the method is capable of designing tunnel vessels precisely and quickly.

The Cryptogenic Red Alga <i>Bangia Atropurpurea</i> in Lough Derg, River Shannon, Ireland

The filamentous and euryhaline red alga Bangia atropurpurea (Rhodophyta, Bangiophyceae) is a littleknown member of the Irish aquatic flora. Although a common freshwater species in the northern hemisphere, it seems that the lower Shannon Navigation is one of the principal freshwater localities for the species in Ireland. It was recorded from thirteen sites in Lough Derg in 1972 and in the 2010 survey reported here at 40 sites including islands and navigation buoys as well as on lock gates. It attaches to rocks and other hard surfaces immediately above and below the waterline. It may have been introduced to Lough Derg on the hulls of commercial vessels. Changes in climatic conditions, eutrophication, competition from other filamentous algae and fluctuating lake levels are all pressures that could affect the sustainability of Bangia within the Shannon Navigation. Nevertheless, this study shows that B. atropurpurea has persisted for at least 40 years in Lough Derg and remains widespread despite highly variable environmental conditions.

THE CRYPTOGENIC RED ALGA BANGIA ATROPURPUREA IN LOUGH DERG, RIVER SHANNON, IRELAND

The filamentous and euryhaline red alga Bangia atropurpurea (Rhodophyta, Bangiophyceae) is a little-known member of the Irish aquatic flora. Although a common freshwater species in the northern hemisphere, it seems that the lower Shannon Navigation is one of the principal freshwater localities for the species in Ireland. It was recorded from thirteen sites in Lough Derg in 1972 and in the 2010 survey reported here at 40 sites including islands and navigation buoys as well as on lock gates. It attaches to rocks and other hard surfaces immediately above and below the waterline. It may have been introduced to Lough Derg on the hulls of commercial vessels. Changes in climatic conditions, eutrophication, competition from other filamentous algae and fluctuating lake levels are all pressures that could affect the sustainability of Bangia within the Shannon Navigation. Nevertheless, this study shows that B. atropurpurea has persisted for at least 40 years in Lough Derg and remains widespread despite highly variable environmental conditions.

STUDY OF WORKING CONDITIONS OF OCCUPATIONAL UPPER EXTREMITY MYOFIBROSIS PATIENTS

In 1982-2001 physical load-related diseases contributed 49.4 % to occupational morbidity in Saint-Petersburg. In the study of 553 blue-collar worker jobs, 56.1 % were found to be connected with physical overloads. It makes the problem of health protection of workers occupationally exposed to unfavorable effects, including muscle strain and overstrain, particularly topical. The object of the study was the working conditions assessment in heavy physical load jobs. Working conditions of plasterers, sinkers, mechanical assemblers, assemblers of metal vessel hulls were studied. Working process severity was shown to be the major common factor for all those jobs.

G/T 190톤급 한국 대형선망 본선의 저항저감에 대한 연구

In this study, hull form of main vessel of Korean large purse seiner fishing industry is developed for the improvement of resistance performance as well as for the satisfaction to the Standard of Fishing Convention, ILO. Through the modification of reference hull form parameters and local characteristics, the hull form development is carried out. The optimum hull form parameters are searched by Sequential Quadratic Programing(SQP) method with the power estimation method of Holtrop & Mannen. To minimize the wave resistance, bulbous bow parameters are determined by the bulbous bow design method of Alvarino. The plasmatic curve is redesigned from that of the reference hull by using Lackenby method. The resistance performances of the reference and designed hull forms are estimated by using numerical simulation method. Also, the judgment of seakeeping ability and the estimation of intact stability for the designed hull form is carried out. As a result, the optimum hull form is proposed. To verify the improvement of resistance performance, model tests are carried out in towing tank. The results show that the resistance of the designed hull form is about 14% smaller than that of the reference hull from at design speed. A new hull form proposed in this study can contribute to the development of the main vessel hull form of Korean large purse seiner fishing system.

A mixed integer programming framework for sonar placement to mitigate maritime security risk

An optimization model is proposed to keep ports and waterways under surveillance against threats from divers, torpedoes or explosives mounted on the hull of vessels. A sonar sensor is utilized for under water detection. The proposed model addresses two key concepts of sensor placement which are mostly ignored in the literature. These features are “multiple coverage” meaning that the detection probability in a section increases as the number of sensors covering that section increases and “range-dependant detection probability” implying that the detection probability decreases as the distance from a sensor increases. The proposed mathematical model is a mixed integer linear programming model. A greedy heuristic approach reaches near-optimal solutions for large scale scenarios. Numerical results are provided to show the accuracy and speed of the heuristic algorithm. It turns out that the algorithm performs reasonably well when the sonars are scarce in the region of interest. This is an advantage for using the heuristic method in real world scenarios, as the density of sonars is low in these scenarios due to the budget limitations.

HEALTH STATUS OF WORKERS EXPOSED TO HEAVY PHYSICAL LOADS AND HAND VIBRATION

Occupational diseases develop while working in unfavorable working conditions, such as whole-body and local physical load, whole-body and local vibration, and cold, etc. The aim of the study was to examine the state of the upper extremi ties musculoskeletal system under occupational exposure to heavy physical loads and hand vibration. Working conditions of 89 plasterers, taking into account adverse effects, corresponded to: 3-rd class, 2-nd degree, harmful heavy work of the 2-nd degree; working conditions of 87 sinkers, 102 mechanical assemblers, 84 assemblers of metal vessel hulls corresponded to the 3-rd class, the 3-rd degree, harmful heavy work of the 3-rd degree. Numerous complaints of hands pain, surgeon objective examination findings, disturbances of muscle strength, the upper extremities microcirculation, creatine phosphokinase activity allowed to diagnose I - II degree miofibrosis in the examined groups. Miofibrosis was combined with vibration disease of the I-II degree in those who worked with vibration instruments.

Biosecurity risks associated with in-water and shore-based marine vessel hull cleaning operations

The removal of biofouling from vessels during hull cleaning can pose a biosecurity threat if viable, non-indigenous organisms are released into the aquatic environment. However, the effect of cleaning on biofouling organism viability in different types of cleaning operations has been poorly studied. We compared the effects of hull cleaning on biofouling organisms removed from 36 marine vessels during in-water (without capture of cleaning waste) and shore-based (with capture, and treatment of cleaning waste) cleaning. In-water cleaning resulted in higher proportions of viable biofouling organisms surviving cleaning (62.3±7.1% of all organisms examined) compared to dry dock (37.8±8.6%) and haul-out (20.1±5.3%) operations. For shore-based facilities with effluent treatment systems, concentrations of organisms and/or their propagules in cleaning effluent was reduced by ⩾98.5% compared to initial hydro-blast effluent concentrations. These results can be used in guidance for hull cleaning operations to minimize associated biosecurity risk.

A binational, supply-side evaluation for managing water quality and invasive fouling species on California’s coastal boats

Integrated solutions are needed for sustainable management of risks posed by recreational boats to coastal water quality and ecosystems. Fouling organisms roughen vessel hull surfaces, creating friction that slows sailboats and increases fuel consumption by powerboats. Hull fouling control strategies for recreational boats that are stored in the water may include antifouling hull paints, newer alternative hull coatings, periodic in-water hull cleaning, and excluding propagules by surrounding the boat with a slip liner or raising it above water on a lift. Copper discharged to harbor waters from antifouling paints via passive leaching and in-water hull cleaning may elevate dissolved copper levels above government standards. Invasive species carried among boat-hull fouling organisms may be introduced as boats move among coastal areas. Some of these species tolerate copper in antifouling paints and copper-polluted harbor waters. Policy development must consider supply-side capacity, as well as economic and environmental sustainability, in managing these issues. This paper presents a supply-side evaluation useful in developing policies to co-manage water quality and invasive species risks for recreational boats navigating along the coasts of California, the Baja California peninsula and California's Sacramento-San Joaquin Delta. Supply-side perspectives on services, materials, costs, and boat owner behaviors, such as residence and travel patterns, awareness of hull-coating choices and selection of hull coatings, are determined. Analyses include evaluation of risks, risk management capacity and costs, and role of education in risk management. The issues raised are broadly applicable, as they are appearing on research and policy agendas in diverse coastal areas.

Evaluating the potential for overpressures from the ignition of an LNG vapor cloud during offloading

Ignition of natural gas (composed primarily of methane) is generally not considered to pose explosion hazards when in unconfined and low- or medium-congested areas, as most of the areas within LNG regasification facilities can typically be classified. However, as the degrees of confinement and/or congestion increase, the potential exists for the ignition of a methane cloud to result in damaging overpressures (as demonstrated by the recurring residential explosions due to natural gas leaks). Therefore, it is prudent to examine a proposed facility’s design to identify areas where vapor cloud explosions (VCEs) may cause damage, particularly if the damage may extend off site. An area of potential interest for VCEs is the dock, while an LNG carrier is being offloaded: the vessel hull provides one degree of confinement and the shoreline may provide another; some degree of congestion is provided by the dock and associated equipment. In this paper, the computational fluid dynamics (CFD) software FLACS is used to evaluate the consequences of the ignition of a flammable vapor cloud from an LNG spill during the LNG carrier offloading process. The simulations will demonstrate different approaches that can be taken to evaluate a vapor cloud explosion scenario in a partially confined and partially congested geometry.

Heavy-Ion Anisotropy Measured by ALTEA in the International Space Station

The uneven shielding of the International Space Station from the vessel hull, racks and experiments produces a modulation of the internal radiation environment. A detailed knowledge of this environment, and therefore of the Station's shielding effectiveness, is mandatory for an accurate assessment of radiation risk. We present here the first 3D measurements of the Station's radiation environment, discriminating particle trajectories and LET, made possible using the detection capability of the ALTEA-space detector. We provide evidence for a strong (factor ≈ 3) anisotropy in the inner integral LET for high-LET particles (LET > 50keV/µm) showing a minimum along the longitudinal station axis (most shielded) and a maximum normal to it. Integrating over all measured LETs, the anisotropy is strongly reduced, showing that unstopped light ions plus the fragments produced by heavier ions approximately maintain flux/LET isotropy. This suggests that, while changing the quality of radiation, the extra shielding along the station main axis is not producing a benefit in terms of total LET. These features should be taken into account (1) when measuring radiation with detectors that cannot distinguish the direction of the impinging radiation or that are unidirectional, (2) when planning radiation biology experiments on the ISS, and (3) when simulating the space radiation environment for experiments on the ground. A novel analysis technique that fully exploits the ability to retrieve the angular distribution of the radiation is also presented as well as the angular particle flux and LET characteristic of three geomagnetic zones measured during 2009 by the ALTEA-space detector. This technique is applied to the ALTEA-space detector, but a wider applicability to other detectors is suggested.

Vessel and voyage determinants of tanker freight rates and contract times

The behavior of shipping freight (charter) rates and the timing of shipping contracts affect the transportation costs of charterers and the operating cash flows of shipowners. Although the literature has established macroeconomic determinants of shipping freight rates, there has been no systematic investigation of microeconomic determinants of freight rates and the delivery time of chartered ships (the laycan period) in the tanker market. Therefore, the aim of this paper is to investigate the importance of vessel and contract specific factors in the determination of tanker freight rates and laycan periods in shipping contracts. Individual tanker shipping contracts from January 2006 to March 2009 are used to estimate freight rates and laycan periods using a system of simultaneous equations. The estimation results suggest that the duration of the laycan period is an important determinant of the shipping freight rate and vice versa. Other determinants of freight rates include the vessel's hull type, fixture deadweight utilization ratio, vessel age, and voyage routes. Determinants of the laycan period include the former determinants as well as the Baltic Dirty Tanker Index and its volatility.