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SOLAS Β· International Convention for the Safety of Life at Sea Β· Reay's Note

SOLAS Regulatory Framework
Summary Note

πŸ“… Updated: 2026-06-02 ⏱ 15 min read 🏷 SOLAS / Retrofit / Survey

After the sinking of the Titanic in 1912, the international community began to reassess the importance of safety of life at sea, leading to the creation of the SOLAS Convention. Today, SOLAS has become the common global safety standard for merchant ships, establishing minimum safety requirements for ship design, construction, equipment, operation, and survey. It remains a core reference for protecting life at sea, maintaining ship compliance, and supporting safe international navigation.

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1. SOLAS Regulatory Framework

The purpose of SOLAS is to set minimum safety standards for merchant ships in relation to construction, equipment, and operation. In practice, it can be understood through three layers: convention text, annex chapters, and mandatory codes and certificates.

1

Convention Text

Sets out contracting government obligations, amendment procedures, entry-into-force mechanisms, tacit acceptance, and the general legal framework.

2

Annex Chapters

Contain the practical technical requirements covering construction, fire safety, life-saving appliances, communications, navigation, cargo, safety management, and security.

3

Mandatory Codes

Examples include the LSA, IMDG, IMSBC, IBC, IGC, ISM, HSC, ISPS, Polar, and IP Codes.

Convention Core Establishes minimum international safety standards and requires flag States to verify compliance through certificates.
β†’
Technical Chapters Each chapter addresses construction, equipment, operations, cargo, special ship types, and special operating areas.
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Project Application Retrofits, certificate renewal, PSC, RO review, and flag State requirements all ultimately return to chapter and certificate compliance.

2. SOLAS Chapter Map

Construction & Equipment Fire & Life-Saving Operations & Management Cargo & Dangerous Goods Special Ships / Areas / Personnel High Retrofit Relevance

Select a chapter tile below to jump directly to its explanation section.

I
General Provisions
Survey, certification, PSC
II-1
Subdivision, stability, machinery & electrical
Survivability and system continuity
II-2
Fire protection, detection & extinction
Fire zones and escape
III
Life-Saving Appliances & Arrangements
Abandon ship, muster, launching
IV
Radiocommunications
GMDSS and SAR communications
V
Safety of Navigation
Navigation equipment, routing, SAR
VI
Cargoes and Oil Fuel
Stowage, securing, grain
VII
Dangerous Goods
IMDG, IBC, IGC
VIII
Nuclear Ships
Nuclear power and radiation safety
IX
Safe Operation Management
ISM and SMS
X
High-Speed Craft
HSC Code
XI-1
Enhanced Maritime Safety
RO, ESP, IMO number
XI-2
Enhanced Maritime Security
ISPS, SSP, SSAS
XII
Additional Safety for Bulk Carriers
Structure and flooding safety
XIII
Verification of Compliance
Member State audit
XIV
Ships Operating in Polar Waters
Polar Code
XV
Carriage of Industrial Personnel
IP Code and transfer safety

3. Key SOLAS Impacts in Ship Retrofit Projects

In response to increasingly stringent international regulations and shipowners' technical upgrade needs, every ship retrofit project should be assessed for SOLAS compliance. A retrofit is often not merely a single equipment change; it can become an integrated compliance exercise involving certificates, stability, fire integrity, life-saving capacity, navigation equipment configuration, and operational procedures.

Relevance Chapter Common Triggers Retrofit Project Checkpoints
High Chapter I Major modification, change of service, or change in certificate particulars Confirm whether the work constitutes a major modification, whether an initial-survey level of verification is required, and whether certificates need reissue or endorsement.
High Chapter II-1 Compartment rearrangement, addition/removal of bulkheads, added weight, or changes to draft or center of gravity Intact/damage stability, subdivision index, bilge drainage, steering gear, emergency power, and machinery/electrical redundancy.
High Chapter II-2 New openings, pipe/cable penetrations, fire door changes, or change of space use A/B class divisions, fire-rated penetrations, smoke detection coverage, fixed fire-extinguishing systems, ventilation dampers, and escape routes.
High Chapter III Change in persons on board, deck arrangement changes, or relocation of lifeboats/liferafts Life-saving capacity, port/starboard arrangements, muster stations, embarkation routes, launching appliances, and rescue boat arrangement.
Medium-High Chapter V Bridge modification, change in tonnage or ship type, or change in operating area AIS, VDR, ECDIS, radar, compass, echo sounder, voyage planning, and safe manning.
Medium-High Chapters VI/VII New cargo types, change of cargo space use, carriage of dangerous goods, or special bulk cargoes Cargo Securing Manual, applicability of IMSBC/IMDG/IBC/IGC, dangerous goods segregation, and documentation.
Medium Chapters IX/XI-2 Changes to operating procedures, security areas, personnel movement, or port operation mode SMS, SSP, emergency procedures, drills, security levels, SSAS, and ship-shore coordination.
Medium Chapters XIV/XV Addition of polar operations or carriage of industrial personnel Polar Ship Certificate, Polar Water Operational Manual, IP Code, industrial personnel transfer, and life-saving arrangements.
Retrofit Assessment Reminder:If a retrofit affects principal dimensions, ship type or service, persons on board, stability, fire divisions, life-saving arrangements, navigation equipment, or certificate particulars, it should not be treated merely as a routine annual survey item. Confirm the submission scope with the flag State and recognized organization first.

4. Chapter Details and Key Notes

I

Chapter I | General Provisions

Core: application, surveys, certification, certificate validity, casualty reporting, and port State control.

Chapter Details

  • Part A: application and definitions, including force majeure exceptions, carriage of persons in emergencies, and other basic rules.
  • Part B: surveys and certificates, the core of this chapter, including initial, annual, intermediate, periodical, and renewal surveys.
  • Part C: casualties and port State control, including PSC inspection and casualty reporting.
  • Common certificates: Passenger Ship Safety Certificate, Cargo Ship Safety Construction Certificate, Cargo Ship Safety Equipment Certificate, Cargo Ship Safety Radio Certificate, and Cargo Ship Safety Certificate.
Memory cue: Chapter I = survey, certification, and control.

Retrofit Project Notes

A major modification may trigger comprehensive verification close to initial survey level. After modification, reconfirm certificate scope, equipment records, survey windows, and flag State requirements.

II-1

Chapter II-1 | Construction: subdivision and stability, machinery and electrical installations

Core: keep the ship afloat and maintain stability and essential machinery/electrical functions after damage.

Technical Notes

  • Subdivision and damage stability: uses a probabilistic damage stability concept; the key is that attained subdivision index A is not less than required subdivision index R.
  • Watertight integrity: watertight bulkheads, watertight doors, hatches, side scuttles, sea valves, collision bulkhead, double bottom, and related items.
  • Machinery installations: main engines, auxiliary engines, steering gear, bilge systems, starting air, and essential auxiliary systems.
  • Electrical installations: main source of power, emergency source of power, emergency switchboard, emergency lighting, and supply to essential loads.
Memory cue: Chapter II-1 = keep the ship afloat and essential systems running.

Retrofit Project Notes

Compartment rearrangement, bulkhead changes, added equipment weight, or changes in draft/center of gravity can affect stability data and damage stability calculations, usually requiring revised stability calculations and drawings.

II-2

Chapter II-2 | Fire Protection, Fire Detection and Fire Extinction

Core: prevent ignition, limit fire and smoke spread, detect early, extinguish quickly, and maintain safe escape.

Technical Notes

  • Fire zoning: uses main vertical zones, thermal barriers, and structural boundaries to limit fire spread.
  • A/B/C class divisions: A class divisions are generally steel or equivalent material, with common ratings such as A-60 and A-30.
  • System requirements: fixed fire-extinguishing systems, fire detection and alarm, firefighter outfits, ventilation fire dampers, and protection of flammable liquid spaces.
  • Special ship types: tankers, passenger ships, vehicle carriers, and ro-ro spaces have additional requirements.
Memory cue: Chapter II-2 = prevention, detection, extinction, and escape.

Retrofit Project Notes

When new openings or pipe/cable penetrations pass through fire divisions, verify the fire rating of penetration seals and review smoke detection coverage, escape distances, fire control plans, and fixed fire-extinguishing coverage.

III

Chapter III | Life-Saving Appliances & Arrangements

Core: govern abandonment, survival, search-and-rescue location, muster, and embarkation arrangements; technical details are supplemented by the LSA Code.

Technical Notes

  • Lifeboats and liferafts: totally enclosed, partially enclosed, and free-fall lifeboats, as well as liferafts and rescue boats.
  • Launching appliances: davits, release gear, embarkation arrangements, and recovery arrangements.
  • Personal equipment: lifejackets, lifebuoys, immersion suits, thermal protective aids, and related equipment.
  • Organization: muster stations, muster lists, alarms, training, drills, operating instructions, and maintenance checks.
Memory cue: Chapter III = abandonment and life-saving.

Retrofit Project Notes

Any increase in persons on board, deck arrangement changes, or relocation/obstruction of survival craft requires recalculation of life-saving capacity, embarkation routes, muster station area, and launching clearance.

IV

Chapter IV | Radiocommunications

Core: use GMDSS to ensure distress alerting, positioning, search-and-rescue coordination, and receipt of maritime safety information.

Technical Notes

  • Sea areas: A1, A2, A3, and A4 determine equipment carriage based on shore station and satellite coverage.
  • Main equipment: VHF DSC, MF/HF DSC, satellite communications, NAVTEX, EPIRB, SART, and related equipment.
  • Availability: can be maintained through shore-based maintenance, reserve equipment, or duplication of equipment.
  • Management requirements: radio watchkeeping, records, personnel qualifications, and distress communication procedures.
Memory cue: Chapter IV = distress alerting and search-and-rescue communications.

Retrofit Project Notes

If the operating sea area, tonnage, or radio equipment configuration changes, recheck the GMDSS equipment list, availability method, antenna arrangement, and radio certificate.

V

Chapter V | Safety of Navigation

Core: most requirements apply broadly and cover navigation equipment, routing, meteorological services, SAR, assistance obligations, and safe manning.

Technical Notes

  • Navigation equipment: magnetic compass, gyrocompass, radar, AIS, VDR, ECDIS, speed log, echo sounder, rate-of-turn indicator, and other equipment.
  • Navigation services: meteorological services, ice information, ships' routeing, ship reporting systems, VTS, and SAR services.
  • Operational requirements: voyage planning, danger messages, obligation to assist persons in distress, and pilot transfer arrangements.
  • Manning requirements: adequate and efficient safe manning.
Memory cue: Chapter V = voyage planning, safe navigation, and assistance in distress.

Retrofit Project Notes

For bridge modifications, changes in ship type or gross tonnage, upgraded operating areas, or new navigation equipment, check applicable tonnage thresholds, redundancy, visibility, power supply, and recording requirements.

VI

Chapter VI | Carriage of Cargoes and Oil Fuel

Core: general cargo, solid bulk cargoes, grain, verified gross mass of containers, and oil fuel safety information.

Chapter Details

  • Part A: general cargo stowage and securing, including cargo information from the shipper and a Cargo Securing Manual on board.
  • Part B: solid bulk cargoes, referring to the IMSBC Code for liquefaction, chemical hazards, and stowage limitations.
  • Part C: carriage of grain, involving heeling moment and stability risks caused by grain shift.
  • Oil fuel note: oil fuel safety information and flashpoint requirements often connect with Chapter II-2 fire risk requirements.
Memory cue: Chapter VI = safe loading and securing of general cargo.

Retrofit Project Notes

When cargo space use changes, deck cargo is added, securing points are changed, or liquefiable bulk cargo is carried, update the Cargo Securing Manual, loading manual, stability information, and operational procedures.

VII

Chapter VII | Carriage of Dangerous Goods

Core: classification, packing, marking, documentation, stowage, segregation, and ship-specific requirements for dangerous bulk liquids and gases.

Chapter Details

  • Part A: packaged dangerous goods, referring to the IMDG Code.
  • Part A-1: solid dangerous goods in bulk, with focus on documentation, stowage, segregation, and incident reporting.
  • Part B: dangerous liquid chemicals in bulk, referring to the IBC Code.
  • Part C: liquefied gases in bulk, referring to the IGC Code.
  • Part D: packaged irradiated nuclear fuel, plutonium, and high-level radioactive waste, referring to the INF Code.
Memory cue: Chapter VII = dangerous goods classification, segregation, documentation, and ship-specific requirements.

Retrofit Project Notes

If a retrofit adds dangerous goods carriage capability, check space fire protection, ventilation, drainage, detection, explosion-protected electrical equipment, cargo segregation, and emergency documentation.

VIII

Chapter VIII | Nuclear Ships

Core: safety assessment, radiation protection, operating documentation, and special controls for nuclear-powered merchant ships.

Technical Notes

  • addresses radiation, reactor safety, and operational risks from nuclear propulsion installations.
  • requires reference to safety standards for nuclear merchant ships.
  • It rarely applies to ordinary merchant ships, but conceptually belongs to a high-risk special ship category.
Memory cue: Chapter VIII = Nuclear power and radiation safety.

Retrofit Project Notes

Ordinary merchant ship retrofits rarely involve this chapter; only ships with nuclear propulsion installations enter Chapter VIII and the related nuclear ship regulatory review.

IX

Chapter IX | Management for the Safe Operation of Ships

Core: mandates the ISM Code and requires the company to establish a safety management system.

Management Notes

  • SMS: safety and environmental protection policy, responsibilities and authority, shipboard operating procedures, and emergency preparedness.
  • DPA: designated person ashore, responsible for ship-shore safety management liaison.
  • Incident management: non-conformities, accidents, hazardous occurrences, reporting, and corrective actions.
  • Certification: the company holds a DOC and the ship holds an SMC.
Memory cue: Chapter IX = prevent accidents through management systems.

Retrofit Project Notes

If a retrofit changes operating processes, equipment maintenance, cargo operations, or manning, update SMS procedures, risk assessments, maintenance plans, and drill content.

X

Chapter X | Safety Measures for High-Speed Craft

Core: makes the HSC Code mandatory and establishes an alternative safety framework for high-speed passenger craft and high-speed cargo craft.

Technical Notes

  • High-speed craft cannot fully follow conventional ship rules because of high speed, light structure, and special handling characteristics.
  • Key areas include structure, buoyancy, stability, evacuation, fire safety, navigational control, and operating limitations.
  • Associated documents usually include a High-Speed Craft Safety Certificate and Permit to Operate.
Memory cue: Chapter X = dedicated safety framework for high-speed craft.

Retrofit Project Notes

High-speed craft retrofits require special attention to weight control, center of gravity, evacuation time, handling performance, structural materials, and permit-to-operate conditions.

XI-1

Chapter XI-1 | Special Measures to Enhance Maritime Safety

Core: strengthens administrative oversight, ship identification, recognized organization authorization, and special ship-type survey requirements.

Management Notes

  • RO: recognized organization authorized by the flag State to conduct surveys and issue certificates.
  • ESP: Enhanced Survey Programme for bulk carriers and oil tankers.
  • IMO ship identification number: permanently marked on the hull, machinery space, or other required locations.
  • CSR: Continuous Synopsis Record documenting ship history and management information.
  • PSC: port States may exercise control over operational requirements.
Memory cue: Chapter XI-1 = identification, survey, and oversight.

Retrofit Project Notes

When ship name, flag, management company, service, or structural survey scope changes, check CSR, IMO markings, ESP, and RO authorization scope.

XI-2

Chapter XI-2 | Special Measures to Enhance Maritime Security

Core: makes the ISPS Code mandatory and establishes security systems for ships and port facilities.

Security Notes

  • Security levels: Levels 1, 2, and 3, with measures adjusted according to threat level.
  • Ship documents: Ship Security Plan (SSP) and International Ship Security Certificate (ISSC).
  • Roles: Ship Security Officer (SSO) and Company Security Officer (CSO).
  • Equipment: Ship Security Alert System (SSAS).
  • Port measures: Port facility security assessment and port facility security plan.
Memory cue: Chapter XI-2 = counter-terrorism, security, and ship-port coordination.

Retrofit Project Notes

When access points, restricted areas, monitoring equipment, cargo flow, or port operation mode changes, update the SSP, security drawings, and drill procedures.

XII

Chapter XII | Additional Safety Measures for Bulk Carriers

Core: sets additional requirements for large bulk carrier structure, safety after flooding, and loading limitations.

Technical Notes

  • The focus is bulk carriers of 150 m in length and above.
  • It regulates cargo hold bulkhead strength, double bottom strength, and ship safety after flooding.
  • It reflects casualty experience involving bulk carrier losses from structural failure, hatch cover water ingress, or cargo risks.
Memory cue: Chapter XII = bulk carrier structural safety.

Retrofit Project Notes

Bulk carrier retrofits should pay particular attention to cargo hold structure, loading manual, hatch cover weathertightness, corrosion margins, ESP surveys, and cargo shift/liquefaction risks.

XIII

Chapter XIII | Verification of Compliance

Core: makes the IMO Member State Audit Scheme mandatory to verify States' implementation capability.

Management Notes

  • It applies to national implementation systems, not individual ship equipment.
  • It audits flag, port, and coastal States' ability to fulfil obligations under IMO instruments.
  • It helps improve consistency and effectiveness in SOLAS implementation.
Memory cue: Chapter XIII = verify whether States implement the requirements.

Retrofit Project Notes

This chapter does not directly regulate retrofit design, but it influences the rigor of flag State and RO implementation.

XIV

Chapter XIV | Safety Measures for Ships Operating in Polar Waters

Core: makes the safety part of the Polar Code mandatory, addressing low temperature, icing, remoteness, and SAR challenges.

Technical Notes

  • Construction: ice class, stability, watertight integrity, and low-temperature materials.
  • Equipment: navigation, communication, life-saving, fire safety, and cold-weather equipment.
  • Operation: Polar Water Operational Manual, voyage planning, operating limitations, and risk assessment.
  • Personnel: training and competency requirements for polar water operations.
  • Certificate: Polar Ship Certificate.
Memory cue: Chapter XIV = special safety for polar navigation.

Retrofit Project Notes

If polar routes are added, check ice-strengthened structure, low-temperature equipment performance, life-saving insulation, communication coverage, the polar manual, and crew training.

XV

Chapter XV | Safety Measures for Ships Carrying Industrial Personnel

Core: regulates ship and personnel safety for the carriage of industrial personnel, especially offshore operations and personnel transfer risks.

Technical Notes

  • Application context: offshore wind farms, oil and gas facilities, aquaculture, seabed mining, maintenance, construction, decommissioning, and service operations.
  • Key risks: personnel transfer, risks from non-traditional passengers, medical fitness, training, muster, and life-saving capacity.
  • Mandatory code: IP Code.
  • Certificate: applicable ships should obtain an Industrial Personnel Safety Certificate and Record of Equipment in accordance with the IP Code.
  • Design interfaces: subdivision stability, machinery/electrical systems, fire safety, life-saving appliances, dangerous goods, and personnel transfer equipment may all be linked.
  • Applicability check: typically confirm whether the ship is a cargo ship of 500 gross tonnage or more or a high-speed cargo ship, and whether it carries more than twelve industrial personnel; industrial personnel should not be treated directly as ordinary passengers.
Memory cue: Chapter XV = offshore industrial personnel carriage and transfer safety.

Retrofit Project Notes

If an existing cargo ship is retrofitted to carry industrial personnel, verify total persons, accommodation, life-saving arrangements, transfer equipment, emergency power, muster stations, medical/training evidence, and whether re-certification under the IP Code is required.

5. SOLAS Mandatory Code Mapping

LSA CodeChapter III: technical details for life-saving appliances and arrangements.
FSS CodeChapter II-2: technical requirements for fixed fire-extinguishing, detection, and fire safety systems.
IMSBC CodeChapter VI: safe carriage of solid bulk cargoes.
Grain CodeChapter VI: grain loading and stability requirements.
IMDG CodeChapter VII Part A: packaged dangerous goods.
IBC CodeChapter VII Part B: ships carrying dangerous liquid chemicals in bulk.
IGC CodeChapter VII Part C: ships carrying liquefied gases in bulk.
INF CodeChapter VII Part D: packaged irradiated nuclear fuel and other special cargoes.
ISM CodeChapter IX: company and ship safety management systems.
HSC CodeChapter X: high-speed craft design, equipment, and operation.
ISPS CodeChapter XI-2: ship and port facility security.
Polar CodeChapter XIV: polar water design, equipment, operation, and training.
IP CodeChapter XV: carriage of industrial personnel and transfer safety.

6. Quick Retrofit Submission Checklist

This checklist can support early retrofit project screening, but does not replace formal flag State or recognized organization requirements.

General arrangement plan, description of space-use changes, and list of affected areas.
Weight estimate, center of gravity change, draft change, and intact/damage stability calculations.
Arrangement of watertight bulkheads, doors, hatches, sea valves, and penetrations.
Fire control plan, A/B class division plan, fire-rated penetrations, and escape route plan.
Fire detection, alarms, fixed fire-extinguishing systems, ventilation fire dampers, and fire-fighting equipment arrangement.
Lifeboats/liferafts, rescue boats, muster stations, embarkation arrangements, and life-saving capacity calculation.
Main source of power, emergency source of power, emergency switchboard, and list of essential loads.
Bridge navigation equipment, GMDSS equipment, antennas, and certificate record updates.
Cargo Securing Manual, loading manual, dangerous goods segregation, and cargo space suitability analysis.
Updates to SMS, SSP, emergency procedures, drill plans, maintenance, and crew training.

7. Recent Update Reminders

Date Key Point Project Reminder
2024/07/01 Chapter XV, Safety Measures for Ships Carrying Industrial Personnel, entered into force and is linked with the IP Code. For offshore wind, oil and gas, and other offshore project vessel retrofits, confirm whether IP Code certification is triggered.
2026/01/01 Chapter II-2 amendments on oil fuel flashpoint require measures to prevent supply of oil fuel that does not meet SOLAS flashpoint requirements. Where fuel systems, bunkering procedures, or fuel documentation are involved, check supplier declarations and flashpoint test method records.
2026/01/01 Recent amendments also affect Chapters II-2 and V, the LSA Code, FSS Code, Polar Code, and related instruments. For fire safety, navigation equipment, life-saving appliances, polar operations, and related equipment retrofits, check the latest requirements item by item.
2028/01/01 Additional Chapter II-1 amendments are scheduled to enter into force. For medium- to long-term newbuilding or major retrofit projects, allow margin for regulatory change during early design.
Practical note:SOLAS continues to evolve through amendments. The applicable version should be confirmed based on the ship construction date, retrofit commencement date, flag State implementation requirements, recognized organization circulars, and the latest convention text.

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Sources

  • IMO: International Convention for the Safety of Life at Sea, 1974.
  • IMO: Amendments to IMO instruments.
  • IMO: Summary of SOLAS chapter II-2.
  • IMO: Summary of SOLAS chapter III.
  • IMO: Polar Code.
  • IMO: Resolution MSC.527(106), IP Code.

This page is intended for learning and preliminary project screening only. It does not replace official convention text, flag State regulations, recognized organization rules, or formal submission comments.