Extended Operational and Trade Vocabulary

Classification Societies and Class Notations glossary

Terminology of classification societies and their notations: IACS members such as ABS, their principal class symbols and rulebooks for building and classing steel vessels, survey software suites, fleet-management systems, and the environmental, structural and machinery notations that record a vessel’s compliance with society rules.

201 defined terms.

A

ABS: American Bureau of Shipping; IACS member classification society.
ABS A1: ABS principal hull classification notation for vessels built and maintained to ABS Rules for unrestricted service.
ABS CyberSafety: ABS class notation framework for cyber resilience.
ABS Eagle: Brand prefix used by ABS for software and rule-related tools, including the Eagle SafeHull and Eagle FPSO suites.
ABS ENVIRO+: ABS environmental protection notation recognising design and operational measures beyond statutory minima.
ABS Nautical Systems: Fleet management software suite owned by ABS.
ABS Rules for Building and Classing Steel Vessels: Core ABS classification rule set covering hull, machinery, and equipment for commercial steel ships.
ABS SafeHull: Direct calculation strength assessment system developed by ABS for tankers, bulk carriers, and container ships.
Accelerated Survey: Survey item credited ahead of its due date, typically within three months prior.
Active Notation: A class notation currently in force on the certificate.
Additional Class Notation: a notation appended to the main class symbol denoting optional or service-specific compliance.
Administration: Government of the State whose flag the ship is entitled to fly, per SOLAS and MARPOL definitions.
Aged Ship Programme: Enhanced inspection regime triggered when a tanker or bulk carrier exceeds 10 or 15 years.
Allowable Wastage: Permissible thickness diminution of hull plating before steel renewal, defined in IACS UR Z10.
Anniversary Date: The day and month corresponding to the expiry date of the relevant class or statutory certificate.
Annual Survey: Survey required at intervals not exceeding three months either side of each anniversary date of a certificate.
Approval in Principle: Preliminary class confirmation that a novel concept design satisfies applicable rules in principle, issued by IACS societies.
Approved Service Supplier: Firm authorized by class to perform UTG, IWS, or service work used for class purposes.
Asbestos Survey: A specialist inspection to identify, sample, and document asbestos-containing materials on board, increasingly required under SOLAS II-1/3-5.
Audit of Recognized Organization: Vertical and horizontal audits conducted by IMO under the RO Code from 2015.
Authorization Agreement: Written agreement between flag State and RO setting out delegated functions, reporting and audit terms.

B

Baltic Notation: Common reference to ICE-class notations such as 1AS, 1A, 1B and 1C.
Bottom Survey: External examination of underwater hull, traditionally in drydock; may be IWS where approved.
Builder's Certificate: Statement by the shipyard certifying particulars and first ownership of a newly built ship, used at first registration.
Bulk carrier additional survey: Expanded inspection element under Paris MoU NIR applied to bulk carriers older than 12 years.
BV: Bureau Veritas, France-headquartered classification society and IACS member founded 1828.
BV I: Bureau Veritas principal class symbol.
BV NR467: Bureau Veritas Rules for the Classification of Steel Ships.
BV Veristar: Bureau Veritas software platform hosting electronic class records.

C

CAP: Condition Assessment Program, voluntary rating scheme operated by ABS, DNV, LR.
Cargo Ship Safety Construction Certificate: Issued under SOLAS I/12, form C.
Cargo Ship Safety Equipment Certificate: Issued under SOLAS I/12, form E.
Cargo Ship Safety Radio Certificate: Issued under SOLAS I/12, form R.
CCS: Cargo Containment System under the IGC and IGF Codes.
Certificate of Class: Document issued by class confirming the vessel is in class.
Certificate of Fitness: The IBC or IGC Code certificate naming the cargoes the vessel is permitted to carry, central to chemical and gas tanker vetting.
Change of Class: Transfer of a ship from one society to another, regulated by IACS PR 1A.
Class Approved Drawings: Plans stamped and endorsed by a class society's plan approval office prior to construction.
Class Maintained: Sellers' obligation to keep class free of recommendations to delivery.
Class Notation: Class society designation reflecting compliance with construction and equipment rules incorporated into SOLAS by reference.
Class Renewal Survey: Five yearly comprehensive class survey equivalent to Special Survey.
Class society: Recognized Organization issuing IEE, IAPP, and DCS-related certificates on behalf of flag states.
Class suspension: Withdrawal of class status by a classification society, often triggering loss of statutory certificates.
Class withdrawal: Permanent cancellation of class by a classification society.
ClassNK: Nippon Kaiji Kyokai, Japanese classification society and IACS member, founded 1899.
ClassNK PrimeShip-GREEN: Tool for EEDI, EEXI and CII verification under MARPOL Annex VI Chapter 4.
ClassNK PrimeShip-HULL: ClassNK rule calculation and direct strength software suite for CSR-BC+OT and NK Rules compliance.
CMS: Continuous machinery survey, alternative class survey regime.
Coating Inspector: NACE or FROSIO certified inspector for newbuild or repair coating works.
Common Structural Rules: IACS harmonized hull rules for bulk carriers and oil tankers, effective 1 July 2015 for new build contracts.
Condition of Class: A class-imposed corrective requirement on the vessel, recorded under VIQ Chapter 2 and weighed by vetting analysts.
Continuous Survey of Hull: Class regime that ends at the final voyage; survival to demolition does not require continued CSH after deletion from class.
Continuous Survey of Machinery: Machinery equivalent of CSH.
Corrosion Addition: Thickness margin added to scantlings per CSR-BC+OT Chapter 3 to account for in-service wastage.
Cross Symbol: Maltese cross prefix used by ABS (+A1), BV (I), LR (+100A1) and RINA.
CRS: Croatian Register of Shipping, IACS member headquartered in Split.
CSR-BC: IACS Common Structural Rules for Bulk Carriers, first edition 1 April 2006.
CSR-H: harmonised IACS Common Structural Rules for Bulk Carriers and Oil Tankers, adopted 2014, in force 1 July 2015 for new contracts.
CSR-OT: IACS Common Structural Rules for Double Hull Oil Tankers, first edition 1 April 2006.
CTF: Coating Technical File required under MSC.215(82).
Cyber Resilience Notation: Class notation implementing IACS UR E26 and E27 from 1 July 2024.

D

Damage Stability Notation: Class addition such as SDS Subdivision and Damage Stability.
Date of Build: Build completion date affecting survey cycles and PSC targeting.
Delegation: Authority granted by flag State to a Recognized Organization.
Det Norske Veritas: Norwegian classification society now part of DNV, founded 1864, IACS member.
DNV: Det Norske Veritas (DNV); IACS member classification society.
DNV +1A1: DNV main class notation indicating a vessel built and maintained to DNV rules for worldwide unrestricted service.
DNV GL: Transitional brand name used 2013 to 2021 after the DNV and Germanischer Lloyd merger.
DNV ShipManager: Maintenance and survey planning software product widely used by tanker and bulker operators.
DOC: Document of Compliance issued to company under the ISM Code.
Drawing Review: First step of newbuilding classification covering general arrangement, midship section, machinery plans.
Drydock Survey: Out-of-water survey of underwater hull, rudder, propeller, and sea valves.

E

EEDI: Energy Efficiency Design Index, MARPOL Annex VI Chapter 4.
EEXI: Energy Efficiency Existing Ship Index, MARPOL Annex VI Chapter 4.
Equivalent Arrangement: alternative to rule requirement accepted by class on demonstration of equivalent safety.
ESP: The Enhanced Survey Programme under IMO Resolution A.1049(27) requiring detailed structural surveys of oil tankers, chemical tankers, and bulk carriers.
ESP Code: IMO 2011 ESP Code (resolution A.1049(27), as amended) consolidating ESP requirements.
ESP File: Onboard dossier containing the Survey Planning Document, thickness measurement records and Condition Evaluation Report.

F

FCBC: Forecastle Bulk Carrier requirement under IACS UR S28.
Final Survey for Class: Newbuilding milestone where the ship receives its Initial Certificate of Class.
Five Year Cycle: Standard interval between consecutive Special Surveys.
Flag administration: Government body responsible for ship registration, certification and oversight of the national fleet.
Flag State Authorization: Documented delegation under SOLAS XI-1/1 and the RO Code.
Float Out Survey: Class attendance at undocking of the newbuilding from the building dock.

G

Gas Carrier Survey: IGC Code specific survey of cargo containment and gas handling systems.
General Particulars: First page of the class certificate listing name, IMO number, type, dimensions and tonnage.
Germanischer Lloyd: German classification society merged with DNV in 2013 to form DNV GL, now operating as DNV.
Grandfathering: Practice of exempting existing ships from new rules.
Gross Tonnage: GT, measure of overall internal volume, determinant of statutory certification thresholds.

H

Harmonized CSR: Common Structural Rules in their 1 July 2015 unified form.
Harmonized System of Survey and Certification: HSSC, IMO scheme aligning survey periodicity for statutory certificates.
Hull Notation: First element of class symbol relating to structural integrity, for example +100A1 or +A1.
Hull Survey: A class or commercial inspection focused on the structural condition of plating, framing, internals, and appendages.

I

IACS: International Association of Classification Societies, 12 members.
IACS Council: highest decision-making body of IACS comprising one representative per member.
IACS Member: Classification society belonging to International Association of Classification Societies.
IACS PR: Procedural Requirement issued by IACS, complementing the Unified Requirements.
IACS Recommendation: Non-mandatory technical guidance issued by IACS Panels.
IACS UR: International Association of Classification Societies Unified Requirements; includes container lashing rules.
IACS UR E26: Cyber resilience of ships (new builds 1 Jul 2024+).
IACS UR E27: Cyber resilience of on-board systems and equipment (new builds 1 Jul 2024+).
IACS UR S1: Bulk carrier longitudinal strength loading guidance.
IACS UR S11: Unified requirement on longitudinal strength.
IACS UR S19: Evaluation of scantlings of corrugated transverse watertight bulkheads in bulk carriers.
IACS UR S25: Cargo hold length limitation for bulk carriers.
IACS UR S31: IACS unified requirement covering renewal criteria for hull structural items, including hold flooding scenarios for bulk carriers.
IACS UR W: Welding Unified Requirements addressing weld procedures, welder qualification, and consumables.
IACS UR Z10: Series covering hull surveys of oil tankers, chemical tankers and bulk carriers.
IACS UR Z17: Procedural requirements for service suppliers.
IACS UR Z18: In water surveys, conditions for credit toward bottom survey.
IACS UR Z23: Bilge keel arrangement.
IACS UR Z3: Periodical survey of machinery.
ICE-1A: Common Finnish-Swedish Ice Class notation.
ICE-1A Super: Highest Finnish-Swedish Ice Class.
IMO Audit: Mandatory Member State Audit Scheme under IMO Res A.1067(28).
IMO Number: Unique seven-digit ship identifier from IHS Markit on behalf of IMO.
In-water survey: Class survey of the underwater hull in lieu of dry docking.
Indian Register of Shipping: IRS, IACS member headquartered in Mumbai.
Initial Certificate of Class: First class certificate issued upon completion of newbuilding surveys.
Initial Survey: First survey before issuance of a certificate under SOLAS I/7-10.
Intermediate Survey: Class survey between Special Surveys.
International Load Line Certificate: SOLAS-related freeboard certificate.
International Oil Pollution Prevention Certificate: IOPP.
International Safety Management Code: ISM Code.
IRS: Indian Register of Shipping.

J

Joint Bulk Carrier Project: IACS programme that produced the original 2006 CSR for Bulk Carriers.
Joint Tanker Project: IACS programme that produced the 2006 CSR for Oil Tankers.

K

KR: See Korean Register of Shipping.
KR +KRS1: KR Hull principal notation indicating construction surveyed by KR.

L

Laid-Up Survey: A periodic condition inspection of vessels in cold or warm layup to monitor preservation measures and detect deterioration.
Light Ship Verification: Lightweight survey by inclining test conducted at delivery.
Lloyd's Register: LR, UK-headquartered classification society and IACS member founded 1760.
Lloyd's Register Foundation: Charitable parent of LR established 2012.
LR 100A1: Lloyd's Register principal class notation for ships built and maintained to LR Rules for unrestricted service.
LR ClassDirect: LR online client portal.
LR LMC: LR Machinery Class.
LR ShipRight: LR's direct calculation and design assessment procedures.

M

Machinery Annual Survey: Examination of main engine, auxiliaries, steering gear, switchboards and emergency systems each year.
Machinery Continuous Survey: Five year survey distributed across approximately one fifth of items per year.
MARPOL Statutory Survey: Examination conducted by the RO for IOPP, IAPP, ISPP certificates.
Maximum Allowable Interval: 36 month maximum between bottom surveys and 60 month maximum for Special Surveys.
Memoranda: Information items recorded on the class certificate, not affecting class status.

N

N*✠: RINA principal class symbol for hull classed by Registro Italiano Navale.
Naval Vessel Rules: Class rules tailored for warships, issued by ABS, BV, DNV, LR.
NDT: Non-destructive testing of welds in monopiles, transition pieces, and jackets.
NDT Operator: Person certified to ISO 9712 Level II.
Net Scantlings: Structural dimensions measured after deducting corrosion additions.

O

Occasional Survey: Class survey arranged outside scheduled cycle for damage or modifications.
Oil Tanker ESP: Application of Enhanced Survey Programme to crude and product oil tankers.

P

Periodical Survey: HKC intermediate or renewal survey of the IHM Certificate.
Permanent Means of Access: PMA arrangements under SOLAS II-1/3-6.
Plan Approval: Class office review and stamping of construction drawings prior to fabrication.
Polar Class: IACS classification system PC1 through PC7 defined in UR I1.
Polish Register of Shipping: PRS, classification society founded 1936 and IACS member.
Port state control: PSC inspection regime.
PRS: Polski Rejestr Statkow, Polish Register of Shipping, IACS member.
PSPC: Performance Standard for Protective Coatings adopted by IMO resolution MSC.215(82).
PSPC-COT: IMO Performance Standard for Protective Coatings for cargo oil tanks of crude oil tankers, Resolution MSC.288(87).

Q

Qualified Coating Inspector: NACE Level II or FROSIO Level III certified individual required under PSPC.
Quality System Certification Scheme: QSCS, IACS internal audit programme.

R

Reactivation Survey: Series of items examined when a vessel is brought out of layup.
Recognized organization: RO, delegated to act on behalf of the flag state.
Recognized security organization: RSO under ISPS Code.
Refit Survey: An attendance during major refit work covering specification, work in progress, and final acceptance.
Registro Italiano Navale: RINA, Genoa based IACS member established 1861.
RINA C: RINA Class principal symbol.
RINA Rules for the Classification of Ships: Italian class rulebook updated each January.
RO Code: Code for Recognized Organizations, see entry above.
Russian Maritime Register of Shipping: Russian classification society, IACS member.

S

SAS: Statutory Authorization Scheme, IACS framework.
Sea Trials: Pre-commissioning tests of naval vessels.
Section Modulus: hull girder property governed by IACS UR-S11 minima.
Service Notation: Class designator describing intended trade.
Service Supplier: Firm approved under IACS UR Z17.
SOLAS XI-1/1: Regulation requiring authorization of ROs in accordance with the RO Code.
Special Survey: The five-yearly comprehensive class inspection involving thickness measurement, internal examination, and extensive testing.
Stability Booklet Approval: Class review of intact and damage stability calculations under IMO IS Code.
Statutory Certificate: Certificate issued under a SOLAS, MARPOL, Load Lines, or Tonnage requirement.
Steel Renewal: Replacement of plating or stiffeners that have wasted below acceptable thickness limits.
Suspension of class: Temporary withdrawal of class status, often resulting in suspension of statutory certificates.

T

Tail Shaft Survey: Class periodic survey of tail shaft and stern tube bearings.
Thickness Measurement: In-service hull gauging required by IACS UR Z10 for ship surveys.
Tonnage Certificate: Statutory certificate of gross and net tonnage.
Type approval: Statutory or class approval of equipment design used onboard.

U

UI: Unified Interpretation, IACS document harmonizing how member societies interpret IMO instruments.
Ultrasonic Thickness Measurement: Standard NDT method for assessing remaining plate thickness.
Unified Requirement: IACS UR, mandatory minimum technical standard.

V

Veritas Petroleum Services: VPS, DNV-affiliated bunker fuel testing laboratory headquartered in Singapore.
Vertical Audit: IMO audit of an RO examining all RO functions for one or several delegations.
Voluntary Notation: Class notation taken at owner's option.
Voyage data recorder: VDR or S-VDR under SOLAS.

W

Wastage Allowance: Allowable reduction of scantling thickness in class.
Watch Free Notation: UMS Unattended Machinery Space notation.
Welding Procedure Qualification: WPQ approved under IACS UR W series.
White list: Top performance category in the Paris MoU and Tokyo MoU flag performance lists.
Window Period: Time band during which a survey may be credited without affecting the cycle.

Y

Yacht Code: Common term for the Large Yacht Code adopted by Red Ensign Group registries for commercial yachts above 24 meters.
Yacht Notation: Class service notation for commercial yachts.

Z

Z-Series: IACS UR-Z series covering survey, certification and class transfer requirements.
Z10 Series: IACS UR on hull surveys of tankers and bulkers.
Zero Outstanding Recommendations: Class status confirming the absence of Conditions of Class.