The article contains a review of IMO's work on development of market-based measures in the context of comprehensive work to reduce greenhouse gas emissions in the shipping sector. Information has been presented about the 2018 Initial IMO Strategy on reduction of GHG emissions from ships and about currently discussed proposals by States and international organizations pursuant to the Initial Strategy on the introduction of various marked-based measures (carbon levy, emission trading scheme). The assessment has been made regarding the development of the so called "package" consisting of market-based and technical measures, due to start in 2023, matters that need to be resolved in that context, as well as possible consequences of the introduction of marked-based measures.

The article examines the existing international and domestic regulatory framework for controlling the carbon footprint left by maritime transport. The aim of the study is to form a methodological approach to the process of determining the carbon footprint of a transport service using ship energy efficiency coefficients. The methods for determining the carbon footprint at the level of organization, product and transport service have been summarized. Recommendations have been given on the use of methods for calculating the carbon footprint of a transport service, based on the design coefficients of the energy efficiency of ships. On the one hand, the domestic regulatory framework creates a toolkit aimed at creating a register of carbon units. On the other hand, its methodological part, related to the calculation of the amount of CO2 equivalent emissions generated in relation to maritime transport, has an archaic structure and does not take into account the relationship between the design characteristics of the ship and its fuel consumption, as well as the transport work performed by the vessel. This does not allow for using the methodology to solve the problems of planning the activities of transport companies aimed at modernizing the fleet and extracting profit from their activities and participating in the trade in carbon units.

The article analyzes the consumption of various types of marine fuel on transport ships, depending on their purpose, according to data published by IMO over the past 3 years. The data on the use of alternative types of fuel on sea-going ships with a gross tonnage of more than 5000 and on ships of the Register class have been given. Conclusions have been drawn about a slight increase in the consumption of alternative fuels, typical for transport ships of all types, with the exception of refrigerators. For all types of ships, an increase in the share of LNG consumption with increasing size is typical. A comparison is made of the volumetric energy capacity of various alternative fuels, which are considered by IMO as promising for use on ships. When compared, the worst performance was found for fuels with zero CO2 emissions: hydrogen, ammonia and electric batteries.

The paper covers vulnerability criterion for stability failure due to broaching during surf-riding suggested by IMO, while also outlining the key factors of the broaching taking into account the research of D.M. Ananyev. It has been demonstrated that a series of computational procedures of vulnerability assessment algorithm does not correspond to essence of the problem formulation and may be excluded. In addition, the Froude number range, at which capturing of the vessel by the following wave realizes, has been specified. The condition of surf-riding on the following wave has been corrected based on the assumption that value frequency of propeller rotation is known. The formulae for calculation of Froude — Krylov forces in the criterion has also been proposed. The correctness of the changes made has been verified by calculating of the vulnerability criterion for six different vessels.

The article discusses the definition of second-order nonlinear forces and the corresponding motions amplitudes based on three-dimensional potential theory. To determine them, the methods of integral equations and the method of a small parameter have been used. Approbation of the second harmonics amplitude calculations by the developed programs has been carried out in comparison with various programs based on the use of two-dimensional methods. Amplitudes of the second harmonics of the change in heading angle and speed have also been studied. Amplitude calculations have been given for various ships. Significant influence of non-linear forces on the amplitudes of heaving and rolling in the zones of superharmonic resonant modes when the ship is positioned in beam waves and the need to take it into account have been shown, as well as the determination of the total amplitude-frequency characteristics performed taking into account the amplitudes of the second harmonics.

The paper presents a comparative analysis of the pressures and accelerations of the ship's motions, obtained by direct hydrodynamic analysis of the ship's linear motions, with the values from the DNV normativeregulatory documents. To carry out direct hydrodynamic calculations of pressures and amplitudes of the ship's roll, the panel method has been used to solve the problem of potential fluid flow around a body. For comparison, an approach has been used based on the determination of equivalent waves that produce the most realistic dangerous states of the ship's hull and the corresponding external loads, taking into account the phase of their action relative to the passage of the wave crest of the position of the ship's midsection. A comparison of long-term responses of parameters of external wave loads based on the approach based on equivalent waves has been given. Comparison of the resulting cross-sectional pressure diagrams demonstrates a qualitative convergence with the pressure patterns presented in the rules for dynamic cases. In the course of the research, a comparison of the obtained pressures and motion parameters from direct hydrodynamic calculations with the corresponding values from the regulatory documents of classification societies has been considered.

One of the problems of strength and rigidity of the hulls of ships with large deck openings is related to hull torsion in waves. The article considers the possibility of introducing diagonal frame elements into the side grillage, which would significantly increase the resistance of the grillage to shear deformations under the torsion of the ship's hull. Introduction of additional members, on the one hand, will lead to the weight increase of the grillage. On the other hand, such introduction will also lead to a decrease in the weight of the main framing due to the decrease in its design span, as well as the weight of the traditional frame grillage due to the redistribution of pressure from the sea to the diagonal elements. As a result, there is a slight increase in the weight of the grillage; at the same time its local strength is ensured, with an obvious increase in the resistance of the grillage to the shear occuring during the torsion of the ship's hull.

Сlose coupled towing is a very difficult marine operation. Insufficient attention to the issue of safety may lead to the temporary lay-up of the ship, financial losses, as well as serious logistical failures along the Northern Sea Route. The purpose of this study is to develop a unified approach to assessing the suitability of a ship for сlose coupled towing. The emphasis in the work is on ships in operation, the key problems of which are the limited time for any engineering studies, and also, often, the incompleteness of the initial data. As a result, the main safety criteria have been formulated, the verification of which, within the framework of a preliminary engineering analysis, will help shortly draw a reasonable conclusion about the suitability of the ship for сlose coupled towing or give appropriate recommendations for its modernization.

The aims of the article is to describe and demonstrate the practical application of analytical heat flow calculation in ship hull and thermal insulation of liquefied gas carriers. Numerical parameters describing the heat flow are used to calculate the amount of boil-off gas evaporating from liquefied gas surface in tank. Also, such numerical parameters are used to define the design temperature of hull structures adjacent to gas containment system. The article gives the results of test heat flow calculations for three ships. Two of the ships are equipped with membrane containment system and have the total cargo capacity of 361000 m3 and 172000 m3 , respectively. The third test ship is equipped with two type C tanks of 2900 m3 capacity each. The calculations corresponding to the standard environment conditions as per industry normative documents have been performed. Reliability of the results, as well as the mathematical model itself, has been checked. Case studies have been done to assess the influence of external conditions to heat flow parameters, both numerically and qualitatively. The results given in the article may be used to improve the requirements of normative documents, and in practical cargo containment system design.

The article substantiates the expediency of developing requirements for ships equipped to use liquefied petroleum gas (LPG) as a fuel. In this regard, the physical and chemical properties of the propane-butane mixture have been considered, an analysis of the requirements for the use of LPG as a fuel for various types of transport has been carried out and data on existing ships using a propanebutane mixture as fuel have also been summarized. Diesel power plants have been considered in the context of their operation on LPG, an analysis of the requirements of the rules of foreign qualification societies and IMO on the issue under study have been carried out. Ultimately, a new Section of Part XVII "Distinguishing Marks and Descriptive Notations in the Class Notation Specifying Structural and Operational Particulars of Ships" of the RS Rules has been developed.

The article presents the main results of research work on the development of requirements for monitoring the vibration state of pipelines of ship systems. The analysis of various technical regulations (ISO and GOST R standards, industry standards for the oil and gas industry and the shipbuilding industry, the Rules of Classification Societies) in terms of the requirements for pipeline vibration control has been carried out. Various types of damage to ship pipelines due to vibration exposure have been considered and analyzed. It has been shown that under operating conditions, a set of static and dynamic loads acts on the mechanisms and pipelines of ship systems, and the combination of the impact of these loads determines the level of vibration in the system "mechanism — pipeline". A criterion for ensuring the protection of ship pipelines from the occurrence of resonance and recommendations for detuning from resonant frequencies has been proposed. Requirements for the control of vibration of ship pipelines have been developed and formed to be included in 1.4, Part VIII "Systems and Pipelines" of the Rules for the Classification and Construction of Sea-Going Ships.

The article presents a description of the approaches to accounting for the impact on offshore structures in the MODU/FOP Register Rules, including random phenomena from wind and waves with a deterministic and probabilistic approach, and features of the calculation of ice loads. The results of calculation of ice load on fixed offshore structures in accordance with the Register rules and comparison of the data with other sources have been presented. The experience of applying the Register rules in computer modeling of marine offshore structures and external loads, as well as the direction of development of the MODU/FOP Register Rules in the field of developing of new approaches to justifying design solutions based on mathematical modeling of the digital twins of offshore structures behavior under the influence of randomly changing natural loads over long time intervals have been discussed.

The results of the physical modeling of interaction of long tsunami-type waves with a floating gas storage are presented in this article. It has been assumed that when transporting liquefied natural gas to Asian countries, such storage facilities will be located in the bays of the Pacific Ocean. This being a tsunami prone, the solution of the problem of determining the forces in anchor system of a floating storage regasification units at their locations from the action of possible tsunami waves is very important. The impact of a separate wave propagating under the action of one external volumetric force (gravity) on an anchored floating object located at a point with a sea depth less than the length of this wave has been considered. Evaluation of forces in anchor system with suspended blocks and devices simulating gravitational anchors under wave action has been made. The analysis of the results obtained has been carried out. Conclusions have been made about the nature of the force's variation depending on the orientation of the floating object relative to the direction of the impact of the tsunami wave and the maximum tsunami height, as well as the sea depth at the location of the anchor link.

The International Maritime Organization (IMO) strives to ensure that each of the 175 Member States properly implements and enforces its mandatory documents relating to maritime safety. In order to assist IMO Member States in this task, IMO has developed the IMO Member State Audit Scheme (IMSAS), under which each IMO Member State is audited periodically in order to assess the degree of compliance with applicable requirements. The IMO audit scheme has had a mandatory status since 2016, and over the past 8 years IMO has accumulated a wealth of experience in conducting and organizing those audits. This experience forms ground for the Member State Guidelines to assist in the preparation for the audit under the IMO Member State Audit Scheme (IMSAS), a supporting document aimed at providing States with guidelines and recommendations on the preparation and passing of IMSAS audits. The Guidelines are currently in the final stage of development in the Subcommittee on the Implementation of IMO instruments (III Subcommittee), their adoption is planned by the IMO Assembly in 2023. In this article, the Guidelines have been examined in detail, the background and prerequisites for their development have been shown, the structure, composition, purpose have been considered, the document as a whole has been assessed from the point of view of achieving the goals set in it. Conclusions have been discussed on the most relevant areas of improvement of the IMSAS framework and its explanatory guidelines, with a view to better implementation and enforcement of IMO instruments. Measures have been proposed to improve the IMO Member State Audit Scheme both in general and in the implementation of its provisions within a single Member State.