Maritime Compliance Glossary - Key Maritime Terminology & Definitions

Maritime Compliance Glossary

A comprehensive reference of key maritime compliance, sustainability, and regulatory terms used across the shipping industry. Use the search bar or alphabet navigation to find definitions quickly.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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A

ABS (American Bureau of Shipping)

A leading international classification society that sets standards for the design, construction, and operational maintenance of marine vessels and offshore structures. ABS provides classification services and statutory certification for ships worldwide.

AIS (Automatic Identification System)

A maritime tracking system mandated by the IMO that uses transponders on ships to automatically broadcast vessel identification, position, course, and speed data. AIS enhances maritime safety, navigation, and security by enabling real-time vessel tracking.

Asbestos

A group of naturally occurring fibrous silicate minerals historically used in shipbuilding for insulation and fireproofing. Due to severe health risks including mesothelioma and lung cancer, asbestos is banned under the Hong Kong Convention and EU Ship Recycling Regulation, and must be documented in a ship's Inventory of Hazardous Materials (IHM).

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B

Ballast Water Management

The process of treating and managing ballast water taken on board ships to maintain stability, in compliance with the IMO Ballast Water Management Convention (BWM Convention). This prevents the transfer of invasive aquatic species between marine ecosystems when ballast water is discharged at different ports.

Biofouling

The accumulation of marine organisms such as barnacles, algae, and mussels on a ship's hull and underwater structures. Biofouling increases fuel consumption, contributes to GHG emissions, and can transfer invasive species between ecosystems. IMO guidelines recommend biofouling management plans for all vessels.

BWT (Ballast Water Treatment)

Systems and technologies installed on ships to treat ballast water before discharge, removing or neutralizing harmful aquatic organisms and pathogens. BWT systems are required under the IMO Ballast Water Management Convention to meet the D-2 performance standard.

C

CBAM (Carbon Border Adjustment Mechanism)

An EU regulation that puts a carbon price on imports of certain goods from outside the EU, designed to prevent carbon leakage and ensure that imported products face the same carbon costs as those produced within the EU. CBAM has implications for maritime supply chains and shipping of carbon-intensive goods.

Read about CBAM & maritime impacts

CBT (Computer Based Training)

Digital training programs delivered via computer or online platforms that enable maritime professionals and crew to complete compliance training, safety courses, and certification programs remotely. CBT enhances knowledge retention through interactive modules and assessments.

Explore VS CBT Training platform

CII (Carbon Intensity Indicator)

An IMO operational measure that rates a ship's carbon intensity (CO2 emissions per unit of transport work) on a scale from A to E. Ships rated D for three consecutive years or E in any single year must submit a corrective action plan. CII is a key component of the IMO's strategy to reduce GHG emissions from shipping.

Track CII with VS ESG Reporting

Class Society

An independent organization that establishes and maintains technical standards for the construction and operation of ships and offshore structures. Class societies such as DNV, Lloyd's Register, and ABS conduct surveys and issue certifications confirming that vessels comply with international safety and environmental regulations.

CME (Circular Maritime Economy)

An economic model applied to the maritime industry that emphasizes reducing waste, reusing materials, and recycling ship components throughout the vessel lifecycle. CME aims to minimize environmental impact by keeping resources in use for as long as possible rather than following a linear take-make-dispose pattern.

Explore VS Circular Maritime Economy

CO2 Emissions

Carbon dioxide released into the atmosphere from the combustion of fossil fuels in ship engines and auxiliary systems. The maritime industry accounts for approximately 2-3% of global CO2 emissions, and the IMO has set targets to reach net-zero GHG emissions from international shipping close to 2050.

Read about reducing CO2 through lifecycle optimization

CSRD (Corporate Sustainability Reporting Directive)

An EU directive that requires companies to report detailed information on their environmental, social, and governance performance using the European Sustainability Reporting Standards (ESRS). CSRD significantly expands the scope and depth of mandatory sustainability reporting for companies operating in the EU, including maritime firms.

Learn about CSRD Reporting

CSDDD (Corporate Sustainability Due Diligence Directive)

An EU directive requiring large companies to identify, prevent, mitigate, and account for adverse human rights and environmental impacts throughout their value chains. For the maritime sector, CSDDD impacts ship recycling practices, supply chain management, and operational standards.

Read the CSDDD summary

CSR (Corporate Social Responsibility)

A business approach in which companies integrate social, environmental, and ethical concerns into their operations and interactions with stakeholders. In the maritime industry, CSR encompasses responsible ship recycling, crew welfare, emissions reduction, and community engagement at port locations.

D

Decarbonization

The process of reducing carbon dioxide and other greenhouse gas emissions from maritime operations through energy efficiency measures, alternative fuels (such as LNG, ammonia, hydrogen, and methanol), and operational improvements. The IMO's revised GHG strategy targets net-zero emissions from international shipping by around 2050.

Support decarbonization with VS ESG Reporting

DNV (Det Norske Veritas)

A leading international classification society and assurance provider headquartered in Norway. DNV provides classification, certification, and advisory services for the maritime, oil and gas, and energy industries, setting standards for vessel safety, sustainability, and environmental performance.

DWT (Deadweight Tonnage)

A measure of how much weight a ship can carry, including cargo, fuel, ballast water, provisions, passengers, and crew. DWT is the difference between the displacement of the ship when fully loaded and when empty, and is a key metric used in shipping contracts and CII calculations.

E

EEXI (Energy Efficiency Existing Ship Index)

A technical energy efficiency measure adopted by the IMO that requires existing ships to meet a minimum energy efficiency standard based on their ship type and size. EEXI applies to ships of 400 GT and above and was enforced from 1 January 2023, requiring ships to improve their design efficiency or implement engine power limitation.

EHS (Environment, Health & Safety)

A multidisciplinary field and management framework focused on implementing practical aspects of environmental protection, occupational health, and workplace safety within organizations. In maritime contexts, EHS encompasses shipboard safety procedures, hazardous materials handling, and environmental compliance.

ESG (Environmental, Social & Governance)

A framework for evaluating a company's performance across three pillars: Environmental (emissions, waste, resource use), Social (labor practices, community impact, diversity), and Governance (board structure, ethics, transparency). ESG reporting is increasingly important for maritime companies seeking to demonstrate sustainability credentials to investors, regulators, and customers.

Explore the VS ESG Reporting Portal

EU ETS (EU Emissions Trading System)

The EU's cap-and-trade system that limits greenhouse gas emissions by requiring companies to hold emission allowances. Since 2024, maritime shipping has been progressively included in the EU ETS, requiring ship operators to monitor, report, and surrender allowances for CO2 emissions from voyages to, from, and between EU ports.

Read about EU ETS & maritime impacts

EUSRR (EU Ship Recycling Regulation)

EU Regulation No. 1257/2013 on ship recycling, which requires EU-flagged ships to maintain an Inventory of Hazardous Materials (IHM) and be recycled only at facilities on the European List of approved ship recycling facilities. EUSRR went beyond the Hong Kong Convention by entering into force earlier and imposing stricter requirements.

Learn about the EU Ship Recycling Regulation

EU Taxonomy

A classification system established by the EU that defines which economic activities are environmentally sustainable. The EU Taxonomy helps direct investment toward sustainable projects, including green shipping, and sets technical screening criteria for activities such as maritime transport and shipbuilding.

F

Flag State

The country in which a ship is registered and whose flag it flies. The flag state has jurisdiction over the vessel and is responsible for enforcing maritime regulations, conducting inspections, and issuing certificates. Flag state responsibilities are defined under UNCLOS and various IMO conventions.

FuelEU Maritime

An EU regulation that sets a maximum limit on the GHG intensity of energy used on board ships calling at EU ports, progressively tightening from 2025 to 2050. FuelEU Maritime encourages the uptake of renewable and low-carbon fuels and applies to ships of 5,000 GT and above on voyages to, from, and between EU ports.

G

GHG (Greenhouse Gas)

Gases that trap heat in the Earth's atmosphere, contributing to global warming and climate change. In the maritime context, key GHGs include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The IMO's GHG strategy aims to reach net-zero emissions from international shipping by around 2050.

GRI (Global Reporting Initiative)

An independent international organization that provides the world's most widely used sustainability reporting standards. GRI Standards help companies, including maritime firms, report on their economic, environmental, and social impacts in a consistent, comparable, and credible manner.

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Green Shipping Corridor

A specific shipping route between two or more ports where zero-emission or near-zero-emission solutions are demonstrated and supported through coordinated action between ports, vessel operators, fuel suppliers, and governments. Green shipping corridors serve as pilot projects to accelerate maritime decarbonization at scale.

H

HazMat (Hazardous Materials)

Dangerous substances found on board ships, including asbestos, PCBs, heavy metals, ozone-depleting substances, and other toxic materials. HazMat must be identified, documented in the ship's IHM, and managed throughout the vessel's lifecycle in accordance with the Hong Kong Convention and EU Ship Recycling Regulation.

Manage HazMat with VS IHM Maintenance

HKC (Hong Kong Convention)

The Hong Kong International Convention for the Safe and Environmentally Sound Recycling of Ships, adopted by the IMO in 2009 and entered into force on 26 June 2025. The HKC requires ships to carry an Inventory of Hazardous Materials (IHM), ship recycling facilities to meet safety and environmental standards, and flag states to ensure compliance.

Learn about the Hong Kong Convention

HSSE (Health, Safety, Security & Environment)

An integrated management approach combining health, safety, security, and environmental considerations into a unified framework. HSSE is widely adopted in the maritime and offshore industries to ensure comprehensive risk management and regulatory compliance across all operational areas.

I

IHM (Inventory of Hazardous Materials)

A comprehensive document listing all known hazardous materials on board a ship, including their location and approximate quantities. IHM is mandatory under both the Hong Kong Convention and the EU Ship Recycling Regulation for ships above 500 GT. The IHM consists of three parts: Part I (ship structure and equipment), Part II (operationally generated wastes), and Part III (stores).

Explore VS IHM Maintenance (VSIMS)

ILO (International Labour Organization)

A United Nations agency that sets international labour standards, promotes rights at work, and encourages decent employment opportunities. The ILO's Maritime Labour Convention (MLC) establishes comprehensive rights and protections for seafarers, covering working conditions, health, safety, and social security.

IMO (International Maritime Organization)

The United Nations specialized agency responsible for the safety and security of shipping and the prevention of marine and atmospheric pollution by ships. The IMO develops and maintains a comprehensive framework of international maritime regulations including SOLAS, MARPOL, and the Hong Kong Convention.

ISM Code (International Safety Management Code)

An international standard for the safe management and operation of ships and for pollution prevention, adopted by the IMO. The ISM Code requires ship operators to establish a Safety Management System (SMS) that includes policies, procedures, and instructions for safe operations and environmental protection.

ISPS Code (International Ship and Port Facility Security Code)

An amendment to SOLAS that prescribes minimum security arrangements for ships, ports, and government agencies. Adopted after the events of September 2001, the ISPS Code establishes a framework for detecting and deterring security threats to ships and port facilities used in international trade.

K

Kyoto Protocol

An international treaty adopted in 1997 that committed industrialized countries to reduce greenhouse gas emissions. While international shipping and aviation were excluded from direct targets, the Kyoto Protocol laid the groundwork for subsequent climate agreements and influenced the IMO's approach to maritime emissions reduction.

L

LCA (Life Cycle Assessment)

A systematic methodology for evaluating the environmental impacts of a product, process, or service throughout its entire lifecycle, from raw material extraction through manufacturing, use, and end-of-life disposal or recycling. In maritime contexts, LCA is used to assess the total environmental footprint of ships, fuels, and components.

Explore VS Life Cycle Assessment Portal

Lloyd's Register

One of the world's oldest and most established classification societies, founded in London in 1760. Lloyd's Register provides classification, certification, and advisory services to the maritime industry, setting standards for ship construction, safety, and environmental performance.

LNG (Liquefied Natural Gas)

Natural gas that has been cooled to approximately -162 degrees Celsius, converting it to a liquid state for storage and transport. LNG is increasingly used as a marine fuel because it produces significantly lower SOx and particulate matter emissions than traditional marine fuels, though methane slip remains a concern.

M

MARPOL

The International Convention for the Prevention of Pollution from Ships, the main international convention covering the prevention of pollution of the marine environment by ships. MARPOL includes six technical annexes covering oil, noxious liquid substances, harmful substances in packaged form, sewage, garbage, and air pollution.

MD (Material Declaration)

A document provided by suppliers and manufacturers declaring the presence or absence of hazardous materials in products, components, or equipment supplied to ships. Material Declarations are essential for maintaining an accurate IHM and ensuring compliance with the Hong Kong Convention and EU Ship Recycling Regulation.

Manage MDs with VS IHM Maintenance

MEPC (Marine Environment Protection Committee)

The senior technical body of the IMO responsible for addressing environmental issues within the scope of the organization. MEPC develops and reviews regulations on the prevention and control of pollution from ships, including amendments to MARPOL, ballast water management rules, and the GHG reduction strategy.

MPS (Marine Procurement System)

A digital platform for managing maritime procurement processes, including the sourcing, ordering, and delivery of vessel stores, spare parts, and equipment. A well-designed MPS streamlines supply chain management and can integrate hazardous material declarations for IHM compliance.

Explore the VS Marine Procurement System (VSMPS)

MRV (Monitoring, Reporting & Verification)

The EU regulation requiring ships above 5,000 GT to monitor, report, and have verified their CO2 emissions and other relevant data for voyages to, from, and between EU ports. The EU MRV regulation is a key data collection tool supporting the integration of shipping into the EU ETS and the FuelEU Maritime regulation.

Simplify MRV with VS ESG Reporting
N

Net Zero

A state in which the greenhouse gases emitted are balanced by an equivalent amount of GHGs removed from the atmosphere. The IMO's revised GHG strategy aims to achieve net-zero GHG emissions from international shipping by or around 2050, requiring a combination of energy efficiency, alternative fuels, and carbon capture technologies.

NOx (Nitrogen Oxides)

A group of highly reactive gases produced during combustion in ship engines that contribute to acid rain, smog, and respiratory health problems. NOx emissions from ships are regulated under MARPOL Annex VI, which sets progressively stricter Tier I, II, and III limits for marine diesel engines depending on their construction date and operating area.

O

ODS (Ozone Depleting Substances)

Chemical substances such as CFCs, HCFCs, and halons that destroy the Earth's protective ozone layer. ODS are regulated under the Montreal Protocol and must be documented in a ship's IHM. Ships are prohibited from carrying equipment containing certain ODS, and existing systems must be properly managed and phased out.

Track ODS in your IHM with VSIMS

Omnibus Package

A legislative proposal by the European Commission to simplify and streamline EU sustainability reporting requirements, including modifications to the CSRD and CSDDD. The Omnibus Package aims to reduce administrative burden while maintaining the core objectives of corporate sustainability transparency, affecting reporting obligations for maritime companies.

Read about the EU Omnibus Package
P

Paris Agreement

An international climate treaty adopted in 2015 under the UNFCCC, committing nations to limit global warming to well below 2 degrees Celsius (preferably 1.5 degrees) above pre-industrial levels. While shipping is not directly covered, the Paris Agreement's goals influence IMO emissions targets and national maritime decarbonization policies.

PCB (Polychlorinated Biphenyls)

A group of synthetic organic chemicals historically used in electrical equipment, paints, and sealants on ships. PCBs are persistent organic pollutants that are toxic to humans and the environment, banned under the Stockholm Convention, and must be identified and documented in a ship's IHM for safe removal during recycling.

Manage PCBs through IHM Maintenance

PFAS (Per- and Polyfluoroalkyl Substances)

A large group of manufactured chemicals known as "forever chemicals" because they do not break down in the environment. PFAS are found in firefighting foams, coatings, and other ship equipment. New EU regulations are increasingly restricting PFAS use, requiring maritime operators to identify and phase out PFAS-containing products.

Read about new PFAS restrictions for fleets

PFOS (Perfluorooctane Sulfonate)

A specific PFAS compound that was widely used in firefighting foams and anti-fouling coatings on ships. PFOS is classified as a persistent organic pollutant under the Stockholm Convention and is listed as a hazardous material that must be documented in a ship's IHM under the Hong Kong Convention and EU Ship Recycling Regulation.

Track PFOS compliance with VSIMS

Port State Control

The inspection regime under which a country's maritime authority inspects foreign-flagged ships visiting its ports to verify compliance with international conventions including SOLAS, MARPOL, and the Maritime Labour Convention. Deficiencies found during port state control inspections can result in detention of the vessel until corrected.

PSC (Port State Control)

The system of harmonized inspection procedures coordinated through regional Memoranda of Understanding (MoU) such as the Paris MoU and Tokyo MoU. PSC officers inspect ships for compliance with international maritime safety, security, and environmental standards, with non-compliant vessels subject to detention and penalties.

R

RFQ (Request for Quotation)

A formal procurement document sent to suppliers inviting them to submit price quotations for specific products or services. In the maritime industry, RFQs are used to source vessel spare parts, stores, equipment, and services, and can include requirements for hazardous material declarations to support IHM compliance.

Streamline RFQs with VSMPS

Risk Assessment

A systematic process of identifying, evaluating, and prioritizing potential hazards and risks associated with maritime operations, regulatory compliance, and environmental impact. Risk assessments are fundamental to the ISM Code, ISPS Code, and various environmental regulations, helping ship operators implement appropriate control measures.

S

SASB (Sustainability Accounting Standards Board)

An organization that sets industry-specific sustainability disclosure standards, now part of the IFRS Foundation. SASB standards identify financially material sustainability topics for 77 industries, including marine transportation, helping companies disclose ESG information that is decision-useful for investors.

Align with SASB using VS ESG Reporting

SDoC (Supplier's Declaration of Conformity)

A document in which a supplier formally declares that the materials, products, or equipment they supply comply with specified hazardous material requirements. SDoCs are essential for IHM maintenance, providing assurance that new materials brought on board do not contain prohibited hazardous substances above threshold levels.

Manage SDoCs with VS IHM Maintenance

Ship Recycling

The process of dismantling end-of-life ships to recover materials for reuse and recycling. Ship recycling is regulated under the Hong Kong Convention and EU Ship Recycling Regulation to ensure it is conducted in a safe and environmentally sound manner, protecting workers and surrounding communities from hazardous materials exposure.

Explore VS Circular Maritime Economy solutions

SRF (Ship Recycling Facility)

A facility authorized to carry out the dismantling and recycling of ships. Under the EU Ship Recycling Regulation, EU-flagged ships must be recycled at facilities included on the European List of approved SRFs. The Hong Kong Convention also requires facilities to develop Ship Recycling Facility Plans and meet safety and environmental standards.

Read about new ship recycling certificate formats

SME (Small and Medium-sized Enterprise)

A business classification for companies that fall below certain size thresholds in terms of employees, revenue, or balance sheet totals. The EU has developed voluntary sustainability reporting standards (VSME) specifically adapted for SMEs, reducing the reporting burden while still enabling meaningful ESG disclosure for smaller maritime companies.

Learn about VSME Reporting

SOC (Statement of Compliance)

A certificate issued by an authorized body confirming that a ship's Inventory of Hazardous Materials (IHM) has been properly developed, verified, and is maintained in accordance with the requirements of the Hong Kong Convention or EU Ship Recycling Regulation. The SOC must be kept on board and renewed periodically.

Obtain and maintain your SOC with VSIMS

SOLAS (Safety of Life at Sea)

The most important international treaty concerning the safety of merchant ships, first adopted in 1914 after the Titanic disaster. SOLAS specifies minimum standards for the construction, equipment, and operation of ships to ensure safety, covering areas such as fire protection, life-saving appliances, navigation, and cargo transport.

Read about new SOLAS developments

SOx (Sulphur Oxides)

Gases produced by the combustion of sulphur-containing marine fuels that contribute to acid rain and respiratory diseases. MARPOL Annex VI imposes a global sulphur cap of 0.50% on marine fuels (reduced from 3.50% in 2020), with even stricter limits of 0.10% in designated Emission Control Areas (ECAs).

Sustainable Shipping

A broad approach to maritime operations that integrates environmental protection, social responsibility, and economic viability. Sustainable shipping encompasses decarbonization, energy efficiency, responsible ship recycling, crew welfare, and compliance with evolving environmental regulations to ensure long-term industry viability with minimal ecological impact.

Advance sustainable shipping with VS ESG Portal
T

TCFD (Task Force on Climate-related Financial Disclosures)

A framework established by the Financial Stability Board that recommends how companies should disclose climate-related financial risks and opportunities. TCFD recommendations cover governance, strategy, risk management, and metrics/targets, and are widely adopted by maritime companies in their ESG and sustainability reporting.

Align with TCFD using VS ESG Reporting

TBT (Tributyltin)

A highly toxic organotin compound formerly used in anti-fouling paints on ship hulls. TBT was found to cause severe damage to marine organisms, particularly shellfish, leading to the IMO's Anti-Fouling Systems Convention which banned the use of TBT-based anti-fouling coatings. TBT must be documented in a ship's IHM if present.

U

UNCTAD (United Nations Conference on Trade and Development)

A UN body that supports developing countries in accessing the benefits of the globalized economy, with significant work in maritime transport. UNCTAD publishes the annual Review of Maritime Transport, analyzing global shipping trends, trade patterns, port development, and the regulatory environment affecting international maritime commerce.

V

VSIMS (Varuna Sentinels IHM Maintenance Server)

The proprietary digital platform developed by Varuna Sentinels for managing Inventory of Hazardous Materials (IHM) compliance. VSIMS enables shipowners and managers to maintain their IHM documentation, track hazardous materials, manage supplier declarations, and ensure ongoing compliance with the Hong Kong Convention and EU Ship Recycling Regulation.

Explore the VSIMS platform

VSMPS (Varuna Sentinels Marine Procurement System)

The digital marine procurement platform developed by Varuna Sentinels that streamlines the procurement of vessel stores, spare parts, and equipment. VSMPS integrates hazardous material declarations into the procurement process, ensuring IHM compliance from the point of purchase while optimizing supply chain efficiency.

Explore the VSMPS Portal

VSME (Voluntary SME Standard)

The Voluntary Sustainability Reporting Standard for Small and Medium-Sized Enterprises, developed by EFRAG as a simplified version of the full ESRS. VSME provides a proportionate framework for smaller companies, including maritime SMEs, to report on their sustainability performance without the full burden of CSRD requirements.

Learn about VSME Reporting
W

Well-to-Wake

A comprehensive method of measuring the total greenhouse gas emissions of a marine fuel across its entire lifecycle, from production (well) through distribution to final combustion on board a ship (wake). Well-to-wake analysis includes both upstream (well-to-tank) and downstream (tank-to-wake) emissions and is used by the FuelEU Maritime regulation to assess the true GHG intensity of marine fuels.

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