Global Marine Classification & GMDSS SRT Survey Guide
Everything technical superintendents, shipowners, and marine masters must know regarding the 12 IACS member classification societies, global Non-IACS registers, survey cycles, and procedural requirements (PR1A, PR1B, PR1C, PR1D) for vessel class entry and transfers.
📢 Class Survey Authorization: Our partnered companies are authorised with all major class to carry our Radio GMDSS SRT Survey onboard vessel.
What is IACS and What is an “IACS Class Vessel”?
IACS stands for International Association of Classification Societies. It is a globally recognized, technically based non-governmental organization that currently consists of 12 member marine classification societies. More than 90% of the world’s cargo-carrying ships’ tonnage is covered by the classification standards established and verified by IACS member societies.
An “IACS class vessel” refers to any commercial ship, offshore unit, or specialized marine craft surveyed and certified by an accredited member of IACS. Because IACS members class over 90% of the global commercial merchant fleet (representing tens of thousands of individual ships), listing every individual vessel is not practical. Instead, a vessel’s IACS status is legally defined by which of the 12 official IACS member societies holds its primary class certificate.
Marine classification is a system for promoting the safety of life, property, and the marine environment through the establishment and verification of technical and engineering standards for the design, construction, and life-cycle maintenance of ships, offshore structures, and marine facilities.
Complete List of the 12 IACS Member Classification Societies
The 12 official IACS member societies represent the pinnacle of maritime technical rigor, flag administration trust, and global insurance acceptance:
Purpose & Role within the IMO
Although IACS is a non-governmental organization, it holds consultative status with the International Maritime Organization (IMO). It provides vital technical support, developing Unified Interpretations (UIs) and Unified Requirements (URs) for international conventions including SOLAS, MARPOL, and Load Line.
These unified interpretations are applied by each IACS member society when acting as a Recognized Organization (RO) certifying statutory compliance on behalf of sovereign flag states. The direct link between international maritime safety conventions and hull/machinery rule requirements is codified within SOLAS.
Duty of Members: The Standard 5-Year Survey Cycle
To remain an IACS member, classification societies must demonstrate continuous compliance with quality management standards verified through periodic audits.
Following design review and yard construction attendance, vessels follow a strict five-year survey cycle to maintain active class status:
- Annual Surveys: Held yearly (+/- 3 months of anniversary date) verifying hull, machinery, safety equipment, and GMDSS radio installations.
- Intermediate Surveys: Carried out between years 2 and 3 with expanded internal inspection of ballast tanks and cargo holds.
- Special (Renewal) Surveys: Held every 5 years with comprehensive non-destructive testing (NDT), ultrasonic thickness measurement (UTM), and dry-dock examination.
Non-IACS Classification Societies: Comprehensive Overview
Classification societies that operate outside the International Association of Classification Societies (IACS) are referred to as Non-IACS classification societies. While IACS members cover over 90% of the world’s cargo-carrying tonnage, non-IACS societies primarily serve regional fleets, smaller domestic vessels, coastal craft, offshore support units, or specific national registries.
Operational Considerations for Non-IACS Fleets
- Regional & Domestic Operation: Ideal for domestic voyages, inland waterways, and flag states where IACS membership is not mandatory.
- Flag State & Insurer Variations: Some major international flag administrations and premier P&I underwriters may require additional surveys or conditional terms for non-IACS vessels.
- Port State Control (PSC) Awareness: Non-IACS vessels operating in international trade often receive heightened focus during Paris MOU, Tokyo MOU, or USCG inspections.
Directory of Notable Non-IACS Classification Societies
Major Regional & Former IACS Societies
- Russian Maritime Register of Shipping (RS) – Russia 🇷🇺 (Former IACS member, withdrawn in 2022)
- Biro Klasifikasi Indonesia (BKI) – Indonesia 🇮🇩
- Vietnam Register (VR) – Vietnam 🇻🇳
- CR Classification Society (CR) – Taiwan 🇹🇼
- Shipping Register of Ukraine (RU) – Ukraine 🇺🇦
- Bulgarian Register of Shipping (BRS) – Bulgaria 🇧🇬
- Korean Classification Society (KCS) – North Korea 🇰🇵
Mediterranean, European & Middle East
- Hellenic Register of Shipping (HRS / HR) – Greece 🇬🇷
- Dromon Bureau of Shipping (DBS) – Greece / Cyprus 🇨🇾
- Phoenix Register of Shipping (PHRS) – Greece 🇬🇷
- International Naval Surveys Bureau (INSB) – Greece 🇬🇷
- Libero Hellenic Register (LHR) – Greece 🇬🇷
- Cyprus Bureau of Shipping (CBS) – Cyprus 🇨🇾
- Dutch Lloyd (DL) – Netherlands 🇳🇱
- Iranian Classification Society (ICS) – Iran 🇮🇷
- Asia Classification Society (ACS) – Iran 🇮🇷
- Iransafinah Bureau of Shipping (IRBS) – Iran 🇮🇷
Panamanian & Americas-Based Societies
- International Register of Shipping (IRS / INTREG) – USA / Panama 🇵🇦
- Overseas Marine Certification Services (OMCS Class) – Panama 🇵🇦
- Isthmus Bureau of Shipping (IBS) – Panama 🇵🇦
- Panama Shipping Registrar (PSR) – Panama 🇵🇦
- Panama Maritime Documentation Services (PMDS) – Panama 🇵🇦
- Guardian Bureau of Shipping (GBS) – USA 🇺🇸
- Registro Brasileiro de Navios e Aeronaves (RBNA) – Brazil 🇧🇷
- Registro Cubano de Buques (RCB) – Cuba 🇨🇺
Asia-Pacific & African Societies
- Ships Classification Malaysia (SCM) – Malaysia 🇲🇾
- MY Classification (MYC) – Malaysia 🇲🇾
- Ocean Register of Shipping (ORSI) – Philippines 🇵🇭
- Maritime Bureau of Africa (MBA) – South Africa 🇿🇦
- Global Bureau of Shipping (GBS) – Regional / Africa 🌍
- African International Register (AIR) – Africa 🌍
Key Differences: IACS vs. Non-IACS Classification
IACS Procedural Requirements (PR1A, PR1B, PR1C, PR1D)
IACS establishes four governing Procedural Requirements (PRs) for ship classification entry, transfer between societies, and class re-entry:
Detailed Breakdown of Each Procedural Requirement
1. PR1A – Transfer of Class Between IACS Societies
Applies to: Ships transferring between any of the 12 IACS member societies (e.g., Lloyd’s Register to DNV, or Bureau Veritas to Türk Loydu).
- Review of all previous classification certificates, historical survey reports, and statutory recommendations.
- Minimal physical re-survey required if all periodic surveys are up to date and no outstanding memos exist.
- A condition survey is mandatory if there are overdue surveys or unrectified conditions of class.
2. PR1B – First-Time Classification of a Vessel (New Entry)
Applies to: Newly built vessels or older ships operating without prior classification applying for first-time IACS membership.
- Exhaustive engineering appraisal of hull scantlings, stability booklet, machinery, electrical schematics, and automation.
- Onboard survey verifying hull thickness, structural welding seams, propulsion alignment, and emergency power systems.
- Full statutory certification under SOLAS (Safety Radio, Safety Equipment, Safety Construction), MARPOL, and Load Line.
3. PR1C – Transfer from a Non-IACS Society to an IACS Society
Applies to: Ships previously classed with a Non-IACS entity (e.g., INSB, IBS, or OMCS) seeking admission into an IACS member society.
- Rigorous full-condition survey covering hull structure, propulsion, auxiliary engines, electrical distribution, and safety systems.
- Verification of previous class certificates and complete survey history from the Non-IACS society.
- Extensive Non-Destructive Testing (NDT) and Ultrasonic Thickness Measurements (UTM) across high-stress hull sections.
4. PR1D – Re-Entry of Ships That Lost IACS Classification
Applies to: Ships previously classed with an IACS member that lost class due to survey defaults, extended cold lay-up, or serious deficiencies.
- Detailed engineering risk evaluation proportionate to the duration of class withdrawal.
- Structural integrity verification, lay-up preservation checks, and clearance of all overdue surveys.
- Full dock trials and sea trials for main engine, steering gear, navigation electronics, and GMDSS consoles.
Survey Requirements for Older Tonnage (10+ & 15+ Years)
Survey intensity escalates substantially with vessel age across all procedural requirements:
Vessels Older Than 10 Years
- Ultrasonic Thickness Measurement (UTM): Mandated for hull plating, cargo holds, and ballast tank structures.
- Machinery Condition Monitoring: Mandatory lube oil analysis, vibration logging, and crankshaft deflection checks.
- Structural Fatigue Assessment: Enhanced inspection of high-stress deck plating and transverse bulkheads.
Vessels Older Than 15 Years
- Mandatory Dry-Docking: Required before class approval under PR1B and PR1C to survey underwater hull and sea valves.
- Close-Up Hull Survey: 100% internal close-up survey of all ballast tanks and cargo holds.
- Steel Renewal Records: Strict metallurgical verification of past steel renewals against original class scantlings.
GMDSS Radio Safety (SRT) Survey Onboard Support
Issuing and renewing the mandatory Cargo Ship Safety Radio Certificate (SRT) under SOLAS Chapter IV requires an annual radio survey by authorized, class-certified radio surveyors.
Authorized Global Survey Attendance
Our partnered companies are authorised with all major class to carry our Radio GMDSS SRT Survey onboard vessel.
Whether your vessel is classed under any of the 12 IACS member societies (ABS, BV, CCS, CRS, DNV, IRClass/IRS, KR, LR, ClassNK, PRS, RINA, TL) or a recognized Non-IACS classification society, our certified technical teams coordinate 24/7 boarding across UAE ports (Dubai, Fujairah, Jebel Ali, Sharjah, Abu Dhabi), India (Mumbai, JNPA, Chennai, Kochi), Egypt (Port Said, Suez Canal), Oman, Singapore, and international anchorages.
Scope of Annual GMDSS Radio Surveys
- VHF & VHF DSC: RF power output, frequency deviation, receiver sensitivity, and automated DSC distress call logging.
- MF/HF Transceiver & Radiotelex: Antenna Tuning Unit (ATU) ground resistance, RF power measurements, and DSC watch receiver check.
- Inmarsat-C & Satellite Systems: Distress alert button interlocks, signal strength, antenna dome inspection, and EGC safety net reception.
- EPIRB (406 MHz & 121.5 MHz): Hex ID / MMSI coding check, hydrostatic release unit (HRU) validity, and strobe burst testing.
- SART & AIS-SART: Radar screen response and AIS position broadcast decoding.
- NAVTEX Receiver: International (518 kHz) and national frequency reception, error rate verification, and message storage.
- Emergency Battery Bank: Load discharge testing under full TX load to verify 1-hour or 6-hour autonomous reserve endurance.
Book an Authorized Class Radio Survey
Secure 24/7 technical boarding, pre-survey equipment calibration, and prompt class surveyor endorsement for IACS and Non-IACS classed vessels worldwide.
Related GMDSS & Radio Survey resources: GMDSS & Radio Survey hub · GMDSS Radio Console (Sea Areas A1, A2, A3, A4): Integration, Power Distribution & Class Survey · Handheld VHF Radio (GMDSS): Marine Service, Statutory Survey & Certification · Jotron Marine Safety Systems: EPIRB, SART, AIS, VDR Capsules & GMDSS Radio Guide · Marinelite Marine Navigation & Bridge Electronics: Anemometers, GNSS, Class-A AIS & GMDSS Guide · Port of Fujairah Bunkering Anchorage — 24/7 Marine Navigation & GMDSS Service Spotlight