Recent developments in offshore rig/ platform evacuation

During severe storms, evacuation systems for offshore rigs and platforms currently in use have proven themselves to be inadequate. Typically, during deployment of a lifeboat, it is often damaged to the point of not being seaworthy before it reaches the ocean surface. This is especially the case for cable-launched boats where a pendulum-like motion of the craft on its cables is often set up. It is less of a problem for free-fall lifeboats. Even when a craft reaches the ocean surface intact, high winds and waves can drive it back against the rig/platform structure. This paper describes the state-of-the-art of evacuation. It focuses on two new systems being developed by the authors in Newfoundland, Canada.     

Flow computations for ship safety problems

A number of ship safety problems involve flow computations. Most of them do not require involved CFD calculations, but can be solved by relatively simple means which, nonetheless, are not state of the art. The problems discussed here are, in order of increasing sophistication: cross-flooding of damaged compartments; evacuation of persons on board a ship; sinking of a damaged ship in still water; accelerations and loads on free-fall lifeboats and damaged ship survival time in a seaway.     

Risk in stability evaluation for floating offshore units

During the useful life of a vessel it undergoes various changes that lead to uncertainties in determining the displacement and center of gravity. Besides upgrading work, the very operation of the platform itself involving constant ballast and oil loading and unloading or the use of maintenance equipment can generates uncertainties concerning the displacement and center of gravity. These, therefore, are the parameters that present uncertainties inherent to the vessel's operations. Taking this into account, one example of the application of uncertainties on the displacement and transversal and vertical center of gravity positions will be presented in the analysis of the static stability of a converted FPSO tanker. Another question raised in this work is the deterministic treatment of certain criteria for the parameters that depend on random factors, such as wind, currents and waves. This paper will present a probabilistic approach for the calculation of the roll angle according to resolution IMO A.562 (environment criteria). The two chosen criteria for this analysis were resolutions IMO A.167 (general criteria) and A.562 (weather criterion).     

Effects of Degrees of Motion Freedom on Free-Fall of A Sphere in Fluid

Free-fall of a sphere in fluid is investigated at a Galileo number of 204 by direct numerical simulations (DNS). We mainly focus on the effects of different degrees-of-freedom (DOFs) of the sphere motion during free-fall. The characteristics of free-fall are compared with those of flow past a fixed sphere. Additional numerical tests are conducted with constraints placed on the translational or rotational DOFs of the sphere motion to analyze different DOFs of sphere motion. The transverse motion contributes significantly to the characteristics of free-fall; it results in the retardation of the vortex shedding, leading to the decrease of the Strouhal number. In addition, the transversal sphere motion exhibits the tendency to promote the sphere rotation. On the contrary, the effects of the sphere rotation and vertical oscillations during free-fall are negligible.     

Photographic monitoring system for observing heavy free-falling objects: Multi-stage design packages of radioactive waste

In the consideration of safety it is required that packages containing radioactive wastes when dumped at sea should keep their integrity and retain their contents until they reach the seabed. Packages containing simulated radioactive wastes (non-radioactive) were tested by a free-fall method at depthsca. 4,300 m in an area for dumping industrial waste off Shikoku Island. Since the weight of the largest package was 4,300 kg, special attention was paid to the connection of a buoyancy system with mooring rope. Descent and ascent velocities of the free-fall system were calculated prior to the experiment. A free-fall experiment with an extremely heavy object, heavier than ever previously reported, was accomplished without trouble by using the free-fall system. Recovery of a camera, flash-light, and other components was successful in each of the three experiments. Successive photographing of the package during descent was made and its integrity was observed using the photographs taken by the recovered camera. The packages remained intact during descent and at least for a short time after arrival on the seabed.     

Hydrodynamic Modeling with Grey-Box Method of A Foil-Like Underwater Vehicle

In this study, a dynamic modeling method for foil-like underwater vehicles is introduced and experimentally verified in different sea tests of the Hadal ARV. The dumping force of a foil-like underwater vehicle is sensitive to swing motion. Some foil-like underwater vehicles swing periodically when performing a free-fall dive task in experiments. Models using conventional modeling methods yield solutions with asymptotic stability, which cannot simulate the self-sustained swing motion. By improving the ridge regression optimization algorithm, a grey-box modeling method based on 378 viscous drag coefficients using the Taylor series expansion is proposed in this study. The method is optimized for over-fitting and convergence problems caused by large parameter matrices. Instead of the PMM test data, the unsteady computational fluid dynamics calculation results are used in modeling. The obtained model can better simulate the swing motion of the underwater vehicle. Simulation and experimental results show a good consistency in free-fall tests during sea trials, as well as a prediction of the dive speed in the swing state.     

Launch and impact of free-fall lifeboats. Part II. Implementation and applications

There is a great interest in a practical method of predicting the behaviour of a free-fall lifeboat, when dropped from an offshore platform or from a ship, in order to assess the risk of injury to the occupants. In particular, for those environmental conditions in which full-scale experiments are very difficult, one can benefit from numerical prediction. The hydrodynamic impact of the boat at water entry is a complex problem and makes the establishment of an analytical prediction method a challenging task.This paper is the second of two articles outlining a practical method for simulating the water entry of a free-fall lifeboat. The first article (Part I: impact theory) [Boef, W. J. C. (1992), Ocean Engng19, 119–138] reviewed the relevant literature on hydrodynamic impact and outlined the theoretical model for the water entry of a lifeboat. This paper discusses the implementation of the lifeboat launch model and a method for evaluating the effects of impacts on the occupants. The results of a comparison with full-scale tests and of a case study are also included.     

Econometric analysis of the ship demolition market

The topic of ship recycling has obtained considerable attention during the last two decades for a variety of reasons with the likelihood of the adoption of a new international convention under the auspices of the International Maritime Organization (IMO). This study applies econometric modeling to a unique data set to provide insight into the dynamics of the ship recycling market. The data set contains information on 51,112 ships over 100 gt and includes 748,621 events over a period of 29 years. The analysis confirms a negative relationship of earnings and a positive relationship of scrap prices for all locations while Bangladesh seems to be more sensitive to changes in earnings than the other locations and more likely demolishes larger and older vessels. The results for flag and ownership vary across scrapping locations with Malta and Cyprus indicating potential importance from a registry perspective. The overall safety profile of a vessel seems to be less important towards the probability of a ship being scrapped. Possible implementation of the convention at EU level will mostly likely affect Turkey while non-ratification of one of the major flags will most likely affect China or Bangladesh.     

The Western European PSSA proposal: a “politically sensitive sea area”

In response to a public demand for action, following a series of high profile marine pollution events in their waters, several European States sought designation, by the International Maritime Organization (IMO), for an extensive marine area as a Particularly Sensitive Sea Area (PSSA). The approval ‘in principle’ of this area as a PSSA led to demands by several States to re-examine and constrain the entire PSSA concept. This paper analyses the European application and the response, by many IMO members, to the decision to approve the application in principle. Consideration is given to the legal basis for such an application as well as the potential implications the decision may have on future PSSA applications.     

A free-fall direct-recording ocean bottom seismograph

A compact and relatively low-cost ocean bottom seismograph has been constructed for use in marine seismic research. The instrument is deployed as a free-fall package and can record for 12.5 days. Signals from a vertical geophone, a hydrophone, and a clock are direct recorded on four channels of 6.35×10^-3 m magnetic tape. A timed-release system returns the instrument to the surface.     

Parametric analysis of performances of free-fall penetrators in deep-ocean sediments

The use of free-fail penetrators is being now actively considered by many national and international organizations as a possible option for the safe final, disposal of high-level radioactive waste in vitrified form within deep-ocean sedimentary geological formations. The present paper describes methods and results of a study aimed at highlighting the effects of a number of different parameters on penetrator performance. This work is intended as a preparation of a new series of tests to be carried out during 1984-1986 to assess the present modeling capabilities in more detail. An initial experiment carried out in March 1983, using large model penetrators (3.25 m long, 0.325 m diameter, weight 1.8 tons in air) has successfully demonstrated that it is feasible to design free-fall vehicles which are capable of reaching terminal velocities of 45-50 m/s and embedding themselves up to thirty meters in clayey deep-sea sediments.     

Behavior of a Large Cylinder in Free-Fall Through Water

This paper presents results of experimental deployment of a large instrumented cylinder of variable nose geometry and center of mass offset (CMO) in free-fall in realistic environment. Data on four tests series in the Gulf of Mexico are presented and analyzed statistically. The stochastic nature of the problem of the cylinder free-falling through water is outlined and described as an input to the subsequent impact burial prediction package. Significance of the CMO on the behavior of the cylinder is underlined. Influence of the release conditions on trajectory is discussed and found to affect the behavior of the cylinders only in the first 3.5 m of free-fall in water. Beyond this depth, quasi-stable (in the mean sense) conditions are achieved. Effects of three different nose shapes-blunt, hemispherical, and chamfered-on cylinder behavior are analyzed and found to have a pronounced influence on the fall trajectory. The blunt nose shape appears to be hydrodynamically most stable in free-fall. Apparent periodicity in motions of all cylinders were noted and were found to be the function of the CMO and nose shape primarily. Implications of these and other findings on modeling and impact burial predictions are discussed.     

Multilateralism in the Straits of Malacca and Singapore

This paper analyzes International Maritime Organization (IMO) involvement in maritime cooperation regime in the Straits of Malacca and Singapore through multilateralism. It begins by introducing the maritime cooperation regime prior to 2001, which was mainly trilateral in nature through Tripartite Technical Expert Group on the Safety of Navigation (TTEG). Although TTEG managed to increase the level of safety of navigation in the Straits of Malacca and Singapore through the implementation of the Traffic Separation Scheme (TSS) in 1981 and Mandatory Ship Reporting System (STRAITREP) in 1998, such cooperation was beset by financial strain and conflict of interests. Subsequently, there was a change in the cooperation regime after 9/11 incident. This paper identifies that the change was contributed by the IMO through a methodology called multilateralism. Three important principles were adopted by IMO in implementing multilateralism in the Straits of Malacca and Singapore, namely generalized principles of conduct (respect for sovereignty and compliance with burden sharing principle under Article 43 of UNCLOS 1982), diffuse reciprocity, and indivisibility. This paper concludes that multilateralism by IMO has transformed trilateral cooperation into multilateral cooperation in the Straits of Malacca, combining state actors (littoral states and user states) and non-state actors (non-governmental organizations and international shipping industries).     

IMO legislation and its implementation: Accident risk,vessel deficiencies and national administrative practices

The article takes as its point of departure the apparently contradictory findings in recent research about accident rates in shipping and IMO implementation records. It is argued here that although IMO conventions have probably greatly improved shipping safety, they cannot credibly be held to be the chief cause of reduced accident rates as claimed in a recent Marine Policy article, when the documented failures of flag state and port state implementation continue to leave vessels sailing with grave deficiencies. The present analysis posits and corroborates a cluster of linked tendencies that jointly undermine IMO implementation. The core problem is IMO’s weak connection to the national maritime administrations, leading to broadly discretionary practices, exacerbated by language difficulties. Adding new rules is no panacea, as new rules in some cases negatively affect the functioning of existing regulations, and sometimes seem motivated mainly to show political alertness. The structural weakness of the IMO/member state link is the core implementation problem that urgently needs to be dealt with if marine safety is to be improved. The concluding section proposes a reform to bring the IMO out of this conundrum and ensure effective implementation.     

Polar stratospheric clouds from satellite observational data

The spectral aerosol-extinction coefficients (SAECs) obtained from SAGE III measurements are used to study the physical and integral microphysical characteristics of polar stratospheric clouds (PSCs). Different criteria for PSC identification from SAEC measurements are considered and analyzed based on model and field measurements. An intercomparison of them is performed, and the agreement and difference of the results obtained with the use of different criteria are shown. A new criterion is proposed for PSC identification, which is based on the estimate of how close the measured vector of the spectral attenuation coefficient is to a model distribution of the PSC ensemble. On the basis of different criteria, cases of PSCs are isolated from all SAGE III observations (over 30000). All selection criteria lead to a qualitatively and quantitatively similar space-time distribution of the regions of PSC localization. The PSCs observed in the region accessible to SAGE III measurements are localized in the latitudinal zones 65°–80° in the Northern Hemisphere and 45°–60° in the Southern Hemisphere during the winter-spring period. In the Northern Hemisphere, PSCs are observed within the longitudinal zone 120° W–100° E with the maximum frequency of PSC observation in the vicinity of the Greenwich meridian. In the Southern Hemisphere, the region of PSC observation is almost the same in longitude but with a certain shift in the maximum frequency of PSC observation to the west. This maximum is observed in the vicinity of 40°W, and the region of usual PSC observation is the neighborhood of 60° of the maximum’s longitude. The physical parameters of PSCs are estimated: the mean heights of the lower and upper boundaries of PSCs are 19.5 and 21.9 km, respectively, and the mean cloud temperature is 191.8 K. The integral microphysical parameters of PSCs are estimated: the total surface of NAT particles S _NAT = 0.41 μm²/cm³; the total volume of NAT particles V _NAT = 1.1 μm³/cm³; and, for all aerosol and cloud particles together, S is 2.9 ± 1.5 at a standard deviation of 2.7 μm²/cm³ and V is 2.8 ± 1.5 at a standard deviation of 4.2 μm³/cm³. A high frequency of PSC occurrence and high values of S and V in PSCs both for all particles and for NAT particles have been noted in January–February 2005 as compared to the rest of the period of SAGE III measurements for 2002–2005.     

豪华邮轮耐波性及救生艇砰击载荷特性研究

利用基于三维势流理论的Wasim软件,系统研究了在不同海况下大型豪华邮轮的耐波性能及作用在救生艇上的砰击载荷。首先计算豪华邮轮在规则波和不规则波中的运动响应,分析航速、浪向和海况对豪华邮轮运动响应的影响规律,然后计算救生艇在不同海况下砰击载荷的变化规律,根据变化规律评估救生艇在实际航行中的安全性。结果表明：豪华邮轮运动响应幅值随着航速和海况的增大整体呈增大趋势,规则波中横摇运动响应幅值在浪向90°时最大;当豪华邮轮处于4级和6级海况时救生艇不发生砰击;当豪华邮轮处于8级海况且航速大于10.29 m/s时救生艇发生砰击,为保证救生艇的安全,邮轮应避免在浪向120°和浪向150°下航行,此时建议邮轮以低于12.35 m/s的航速迎浪180°航行。     

STCW ’95: implementation issues: What is the pass mark?

By 1 August 1998 Regulation I/7 of the 1995 amendments to the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (1978) requires a comprehensive submission of information to the International Maritime Organization supporting an Administration’s claim that it complies fully with, or is in the process of implementing, STCW ’95 via policy and legislative processes. Once the complete information is received by the International Maritime Organization, the Secretary-General must submit a report to this effect to the Maritime Safety Committee. Three questions emerging from this controversial provision in STCW ’95 are:

• •When, if ever, is the information from an Administration complete?
• •What is the time frame allocated for confirmation by the IMO Secretariat?
• •How does IMO assess whether the claim by an Administration is valid?

The absolute nature of the phraseology within Regulation I/7, in the author’s view, handcuffs the certification verification process by ‘competent persons’. Equally unfortunately for Administrations, STCW is mute on establishing time frames for the processing of their submissions within IMO. Conceivably, a submission by a proponent aspiring for ‘white listing’ may be delayed sufficiently long for the Secretary-General’s report to miss the MSC regular meetings. What would be the impact of such a delay?Perhaps of greater importance though are two key issues linked to the third question. These issues lie at the heart of the amendments to STCW. Firstly, there is not an appeal or challenge mechanism to IMO’s decision; whether it is favourable or not. It is difficult to gauge at this time either the international shipping community’s reaction to an unfavourable report by IMO or an Administration’s position/policy to recognize a chastised Party’s submission. Secondly, the notion of ‘black- listing’ an Administration for sub-standard marine certification and training may not be sustainable under international jurisprudence. Advocates for IMO’s new role as a ‘watchdog’ of global marine certification and standardization organ for the United Nations would, no doubt, take a contra-position.This article attempts to illuminate the complexity of issues nested within Regulation I/7 of STCW ’95. Emerging controversy could strain international relations to such an extent that the high aspirations of the Convention’s drafters for marine certification transparency may not be realized.