Extended Operational and Trade Vocabulary

Naval Architecture Software and IACS Rules glossary

The design-software and class-rule vocabulary: the ABS class notations (A1, AMS), the Eagle SafeHull and FPSO software suites, the Common Structural Rules, and the FEA and rule-check tools used in ship design. Grounds each term in the classification rule or the naval-architecture software it belongs to.

507 defined terms.

Showing 250 on this page (page 1 of 3).

A

Abaqus: Nonlinear finite element analysis suite developed by Dassault Systemes under the SIMULIA brand, widely used for ship structural and impact studies.
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 AMS: ABS notation for machinery built, installed and tested per ABS Rules under the Automated Machinery Space program.
ABS Eagle: Brand prefix used by ABS for software and rule-related tools, including the Eagle SafeHull and Eagle FPSO suites.
ABS Guide for Building and Classing: Series of ABS technical publications setting requirements for specific vessel and offshore unit types.
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.
Acceptance Criteria: The internal screening thresholds an oil major or charterer applies to a vessel's inspection record, age, class, and operator history before issuing a voyage approval.
Added mass: Apparent increase in vessel mass due to fluid acceleration around the hull during motion.
Aft Perpendicular: Reference station at the after side of the rudder post or rudder stock centerline used in naval architecture drawings.
AIAA Mesh Quality Metrics: Generic mesh quality measures (skewness, aspect ratio, orthogonality) reported by CFD preprocessors including ANSYS Meshing and STAR-CCM+.
Aker Arctic: Finnish naval architecture firm in Helsinki specializing in icebreakers and ice-class merchant ships, originator of the ARC and double-acting tanker concepts.
Allowable Still Water Bending Moment: Maximum hogging or sagging bending moment permitted by class rules in calm water for a given loading condition.
Allowable Stress Method: Traditional design approach comparing computed stress against a permissible fraction of yield, used in legacy IACS UR S formulations.
Anchor Equipment Number: Dimensionless number defined by IACS UR A1 governing the size and number of anchors, chain cable, and mooring lines.
ANSI/AISC 360: US structural steel specification occasionally referenced for shipyard steel structures and offshore topsides.
Ansys: Multidisciplinary simulation software vendor whose Fluent, CFX, Mechanical, AQWA, and LS-DYNA products are widely used in shipbuilding.
Ansys AQWA: Hydrodynamic diffraction and time-domain mooring analysis suite from Ansys used for offshore floaters and moored vessels.
Ansys CFX: Element-based finite volume CFD solver from Ansys applied to turbomachinery and propeller flow studies.
Ansys Fluent: General-purpose CFD solver from Ansys widely used for ship resistance, propulsion, and ventilation studies.
Ansys Mechanical: Implicit finite element analysis solver from Ansys used for ship structural strength, vibration, and fatigue assessment.
API: American Petroleum Institute, standards body whose recommended practices (API RP 2A, 2SK, 2RD) cross over into offshore vessel design.
Appendage resistance: Drag contribution of rudders, bilge keels, shafts, brackets, bossings, and stabilizer fins.
Approval in Principle: Preliminary class confirmation that a novel concept design satisfies applicable rules in principle, issued by IACS societies.
AutoCAD: Foundational 2D and 3D CAD platform from Autodesk underlying ShipConstructor and several shipyard production drawing workflows.
Autodesk Inventor: Parametric mechanical CAD from Autodesk used for shipboard equipment, foundations, and outfitting components.
AVEVA Diagrams: Schematic diagramming module within the AVEVA Marine and AVEVA Plant suites used for P&IDs and electrical schematics.
AVEVA E3D Design: Enterprise 3D plant and marine design platform from AVEVA, successor architecture to PDMS and AVEVA Marine.
AVEVA Hull: Hull design module within AVEVA Marine, derived from Tribon, supporting plate and stiffener modeling for production.
AVEVA Marine: Integrated shipbuilding CAD/CAM suite from AVEVA combining hull, outfit, and diagrams capabilities derived from Tribon M3.
AVEVA Outfitting: Module within AVEVA Marine for piping, HVAC, cable trays, and equipment arrangement modeling.
AVEVA PDMS: Plant Design Management System, predecessor 3D plant design product from AVEVA still used in some yards and topsides projects.
Axial Induction Factor: Coefficient in propeller blade element momentum theory describing axial flow acceleration through the disk.

B

Backbone Curve: Locus of peak response amplitudes versus frequency used in nonlinear ship motion identification.
Ballast Water Management Convention: IMO convention triggering tank coating, pumping, and treatment requirements often modeled in NAPA Loading Computer.
Barehull Resistance: Calm water resistance of a hull without appendages, the base quantity in Holtrop-Mennen and Hollenbach methods.
Baseline: Line from which the breadth of maritime zones is measured.
Bayesian Calibration: Statistical technique used to tune CFD and seakeeping models against towing tank data.
Bentley OpenShip: Bentley Systems integrated ship design and analysis platform building on MicroStation and the MAXSURF family.
Bilge keel: Longitudinal fin on the turn of bilge to damp roll motion.
Block Coefficient: Ratio of displaced volume to the product of length, beam, and draft, a key input to empirical resistance methods.
BMT Group: UK maritime engineering consultancy whose REMBRANDT simulator and SeaSafe tools are used in naval architecture.
Bonjean curves: Sectional area versus draft used in hydrostatic calculations.
Boundary Element Method: Numerical technique discretizing only body surfaces, used in WAMIT, AQWA, and WADAM for potential flow hydrodynamics.
Bow Flare Slamming: Forward impact accelerations, particularly severe in CSS Annex 13 forward-zone factors.
Box-Modeling: NURBS surface modeling technique in Rhinoceros used for early-stage hull form definition.
Buckling Utilization Factor: Ratio of applied stress to buckling capacity per IACS Common Structural Rules Chapter 8.
Bulk Carrier: Single-deck ship for unpackaged dry bulk.
Bulkhead Deck: Uppermost deck to which transverse watertight bulkheads extend.
Bulkhead Stool: Lower or upper triangular structure supporting transverse corrugated bulkheads in bulk carriers, addressed in IACS UR S18.
Bureau Veritas: French classification society delegated by some flag States to approve MET programs and issue MLC certificates.
BV Hull: Bureau Veritas direct calculation tool for hull structural assessment under NR 467 and CSR-BC+OT.
BV Mars 2000: BV legacy software for cross-sectional and 3D FEM analysis of ship structures.
BV NR 467: Bureau Veritas Rules for the Classification of Steel Ships, the principal BV class rule set.

C

CAD/CAM/CAE Integration: Workflow linking design (CAD), manufacturing (CAM), and engineering analysis (CAE) data in shipyard production.
CADMATIC: Finnish CAD/CAM/CAE software developer whose marine suite covers hull, outfitting, electrical, and information management.
CADMATIC Electrical: CADMATIC module for shipboard cable routing, schematics, and equipment registers.
CADMATIC Hull: Steel detail design module within CADMATIC supporting plate, stiffener, and seam modeling for production output.
CADMATIC Outfitting: 3D plant and ship outfitting design module from CADMATIC for piping, HVAC, and equipment.
CAE: Computer-aided engineering, the umbrella term for simulation tools such as FEA, CFD, and multibody dynamics.
Cargo Hold Analysis: Three-cargo-hold FEM analysis required by IACS CSR-BC+OT for direct strength assessment.
Cargo Hold Length Limit: Maximum bulk carrier hold length per IACS UR S25, addressing flooded condition strength.
Cargo Tank Analysis: Three-tank FEM analysis required by IACS CSR-BC+OT for oil tankers under multiple load cases.
Cauchy Number: Hydroelastic similarity parameter relating fluid pressure to structural stiffness in slamming and sloshing studies.
Cavitation bucket: Pressure/angle envelope outside which a section cavitates.
CCS: Cargo Containment System under the IGC and IGF Codes.
CCS CSA: China Classification Society additional notation CSA for direct strength and fatigue assessment of hull structures.
CD-adapco: Original developer of STAR-CCM+ acquired by Siemens in 2016 to form Siemens Digital Industries Software.
CFD: Computational fluid dynamics used for offshore structure hydrodynamic loading.
Chained Equations: Coupling scheme used in fluid-structure interaction codes such as STAR-CCM+ with Abaqus.
Charpy V-Notch: Impact toughness test referenced by IACS UR W11 for hull structural steel grades.
Chord Length: Straight line distance from leading to trailing edge of a propeller or appendage section.
ClassNK: Nippon Kaiji Kyokai, Japanese classification society and IACS member, founded 1899.
ClassNK PrimeShip-HULL: ClassNK rule calculation and direct strength software suite for CSR-BC+OT and NK Rules compliance.
Closed bus tie: Switchboard operation with main busbar continuously closed.
CN Tower Effect: Informal term for downwash interaction between superstructure blocks evaluated in wind CFD studies.
Coastal Service Notation: Restricted navigation notation issued by IACS societies limiting permissible operating area.
Common Structural Rules: IACS harmonized hull rules for bulk carriers and oil tankers, effective 1 July 2015 for new build contracts.
Compass IS: Spanish software company developer of Tdyn CFD and FEA suite used in marine and industrial simulation.
Constant Pressure Loading: Hydrostatic and hydrodynamic pressure scheme applied to FEM models per CSR-BC+OT load cases.
Container Ship Whipping: Transient vibration following bow slamming addressed in IACS UR S30 hull girder strength.
CONTROLLER NOTATION: Class notations covering propulsion control systems such as ABS ACC and ACCU.
Corrosion Addition: Thickness margin added to scantlings per CSR-BC+OT Chapter 3 to account for in-service wastage.
Coupled Eulerian-Lagrangian: Solver technique in Abaqus used for sloshing and grounding impact simulations.
Cradle Loads: Reaction forces on a vessel sitting in a building or repair cradle, modeled in MAESTRO and Poseidon.
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-BC+OT: Harmonized IACS Common Structural Rules for Bulk Carriers and Oil Tankers, effective 1 July 2015 for new contracts.
CSR-OT: IACS Common Structural Rules for Double Hull Oil Tankers, first edition 1 April 2006.
CTS: Container Securing Test or Cargo Tank Securing requirements as defined in IACS UR C and CSC.
Cumulative Fatigue Damage: Linear Miner's rule sum used in CSR-BC+OT fatigue assessment of hot spot details.
CYBR Notation: Cyber security class notations issued by IACS societies aligned with IACS UR E26 and E27.

D

Damage Stability: Required for passenger and cargo ships under SOLAS II-1, Parts B-1 and B-2.
Damping Ratio: Fraction of critical damping used in seakeeping and structural dynamic analyses.
DEFLECTION CRITERIA: Class limits on local panel and frame deflections under design loads.
DELFTship: Hull surface and hydrostatics modeling software derived from FREE!ship and developed by DELFTship BV.
Design Wave Method: CSR-BC+OT direct strength approach using regular waves selected to maximize specific response parameters.
Det Norske Veritas: Norwegian classification society now part of DNV, founded 1864, IACS member.
DFBI: Dynamic Fluid Body Interaction module in STAR-CCM+ for resolving ship motions in waves.
Diffraction Analysis: Solution of the linearized wave diffraction problem in codes such as WADAM, WAMIT, and AQWA.
Direct strength analysis: Finite-element check against IACS Common Structural Rules.
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 GeniE: DNV Sesam structural FEM modeling tool for ships and offshore structures.
DNV HydroD: DNV Sesam hydrodynamic preprocessing tool for stability, WADAM, and WASIM analyses.
DNV NAUTICUS Hull: DNV rule calculation and direct strength assessment software for CSR and DNV rule compliance.
DNV Poseidon: DNV rule scantling and longitudinal strength software for ship hull structural assessment.
DNV PULS: Panel Ultimate Limit State buckling code from DNV used in direct strength assessment per CSR-BC+OT.
DNV Rules for Classification of Ships: DNV's principal rule set for hull, machinery, and equipment of seagoing ships.
DNV Sesam: Integrated DNV software suite for hydrodynamic and structural analysis of ships and offshore structures.
DNV Sesam Manager: Workflow management front end coordinating Sesam modules such as GeniE, HydroD, and Wadam.
DNV Sesam Wadam: Linear potential flow seakeeping solver in the DNV Sesam suite.
DNV Sesam Wajac: Wave load on jacket structures module in the DNV Sesam suite.
DNV Sesam Wasim: Time-domain seakeeping and slamming solver in the DNV Sesam suite.
DNV Sesam Xtract: Sesam postprocessor for result visualization and FEM data interrogation.
Double Bottom Height Rule: SOLAS regulation defining minimum double bottom height aligned with IACS UR S17.
Double Hull Tanker: Oil tanker configuration mandated by MARPOL Annex I and addressed by IACS CSR-OT.
Drag Coefficient: Dimensionless parameter quantifying air-sea momentum transfer.
Dry Docking Loads: Block reactions during docking, modeled in MAESTRO and DNV Poseidon for class approval.
DWT: Deadweight tonnage; conventional LNG carriers typically 80,000 to 100,000 DWT.
Dynamic Allowable Stress: Higher permissible stress allowed under dynamic load cases in CSR-BC+OT compared to static cases.
Dynamic Equilibrium Method: Iterative scheme used in DFBI and Star-CCM+ to balance hydrodynamic forces and ship inertia.

E

EEDI: Energy Efficiency Design Index, MARPOL Annex VI Chapter 4.
Eigenmode Analysis: Solution for natural frequencies and mode shapes performed in Ansys, Abaqus, and Sesam Sestra.
Element Birth and Death: Abaqus and Ansys capability used to simulate weld sequencing in shipyard distortion studies.
Empirical Friction Line: Curve such as ITTC 1957 used to extrapolate model resistance to full scale.
Endurance Limit: Stress amplitude below which an SN curve assumes infinite fatigue life in CSR-BC+OT detail categories.
Energy Efficiency Existing Ship Index: MARPOL Annex VI metric for in-service ships triggered after 2023.
Engine Bedplate Vibration: Coupled engine-foundation dynamic analysis performed in Ansys and Abaqus to satisfy IACS UR M68.
Engineering Equation Solver: Simultaneous equation solver used for early-stage naval architecture estimation.
Equivalent design wave: Single regular wave reproducing a target long-term load.
Equivalent Plate Method: Smeared stiffener idealization technique in MAESTRO and ABS SafeHull coarse mesh models.
Eulerian Free Surface: Volume-of-fluid technique used in STAR-CCM+ and OpenFOAM for ship wave resistance simulations.
Eurocode 3: European structural steel design code occasionally referenced for shipyard structures and offshore topsides.
Excitation Forces: Wave-induced forces on a fixed body computed by diffraction codes such as WADAM and AQWA.
Explicit Dynamics: Time-marching solver branch in LS-DYNA, Abaqus/Explicit, and Radioss used for ship collision and grounding studies.
Explosion Loads: Blast pressure time histories applied in NORSOK-aligned offshore structural assessment.
Extended Wave Statistics: Long-term wave scatter data used in fatigue spectral analysis per IACS Recommendation 56.
External Pressure: Hydrostatic and hydrodynamic pressure on the hull governed by CSR-BC+OT Chapter 4.

F

Fatigue Damage Ratio: Sum of partial Miner's rule contributions used in CSR-BC+OT fatigue acceptance checks.
FEA: Finite element analysis, numerical method underlying Abaqus, Ansys Mechanical, MSC Nastran, and DNV Sestra.
FEM Mesh Density: Element size guidance defined in CSR-BC+OT for coarse, fine, and very fine mesh fatigue analyses.
FineMarine: Marine CFD suite originally from Numeca, now part of Cadence Design Systems' marine offering.
Finite Volume Method: CFD discretization scheme underlying STAR-CCM+, Ansys Fluent, and OpenFOAM.
First Principles Analysis: Direct calculation alternative to prescriptive rules, recognized by IACS UR S11.
First Strake: Plate strake adjacent to the keel addressed by IACS UR S23 thickness requirements.
Fixed-Free Beam: Idealization used in legacy hull girder strength estimation prior to full FEM modeling.
Flag administration: Government body responsible for ship registration, certification and oversight of the national fleet.
Flow Solver Convergence: Residual reduction criteria reported by STAR-CCM+, Fluent, and OpenFOAM for ship CFD runs.
FLOWTECH: Swedish CFD developer behind SHIPFLOW, specializing in viscous and potential flow ship hydrodynamics.
Fluent: General-purpose CFD solver from Ansys widely used for ship resistance, propulsion, and HVAC studies.
Foran: Shipbuilding CAD/CAM/CAE system from SENER (Spain) covering hull, outfitting, electrical, and accommodation.
Foran B-Naval: SENER Foran module dedicated to naval ship design including weapons systems and survivability features.
Form Factor: Resistance multiplier k accounting for three-dimensional viscous effects in ITTC 1978 extrapolation.
Forward perpendicular: vertical reference at the bow used for LBP measurement.
Frame spacing: Longitudinal distance between transverse frames.
Free Surface Effect: Stability reduction accounted for under SOLAS II-1 stability calculations.
FREE!Ship: Open-source hull surface modeling program, predecessor to DELFTship.
Friction Line: Empirical curve such as ITTC 1957 or Schoenherr used in resistance extrapolation.
Froude Number: Ratio of inertia to gravity forces governing wave-making resistance in ship hydrodynamics.
Froude-Krylov Force: Pressure force computed from the undisturbed incident wave field used in seakeeping codes.
FuelEU Maritime: European Union regulation imposing greenhouse gas intensity limits on shipping fuels, driving development of pooling mechanisms and compliance instruments.
Full Scale Trial: Sea trial used to validate Holtrop-Mennen and Hollenbach predictions against actual performance.

G

Galerkin Method: Weighted residual technique underlying many finite element implementations in Abaqus and Ansys.
General Arrangement: Top-level 2D plan and section drawing produced from NAPA Designer, AVEVA Marine, or Foran.
GeniE: DNV Sesam structural modeling tool used for FEM construction and CSR-BC+OT direct analysis.
Geosim Series: Family of geometrically similar models tested at multiple scales to validate scale effect models.
Germanischer Lloyd: German classification society merged with DNV in 2013 to form DNV GL, now operating as DNV.
Ghost Cell Method: Boundary treatment used in some immersed boundary CFD solvers for ship motions.
GHS: General HydroStatics, naval architecture stability software from Creative Systems used for intact and damage stability.
Girder Strength: Hull girder longitudinal strength governed by IACS UR S11 and S11A.
Global FE Model: Full ship FEM idealization used in CSR-BC+OT very fine mesh hot spot analysis.
GMDSS: Global Maritime Distress and Safety System under SOLAS Chapter IV.
Goal-Based Standards: IMO framework triggering CSR-BC+OT and influencing future IACS rule development.
Grasshopper: Visual programming plugin for Rhinoceros used for parametric hull form generation and optimization.
Green Water Loading: Deck wetness load addressed in CSR-OT and IACS UR S33 for tanker bow structures.
Grid Convergence Index: Roache method metric for CFD spatial discretization error reported in ship hydrodynamics studies.
Gross Tonnage: GT, measure of overall internal volume, determinant of statutory certification thresholds.

H

Hammitt Erosion Model: Empirical cavitation erosion estimator used in propeller cavitation studies.
Harmonized Common Structural Rules: 2015 update merging CSR-BC and CSR-OT into a single CSR-BC+OT document.
Hatch Cover Strength: Bulk carrier hatch cover rule requirements governed by IACS UR S21 and S21A.
Heave: Vertical translational motion.
Helmholtz Equation: Reduced wave equation solved in frequency-domain potential flow seakeeping codes.
Hexagon Smart3D: 3D plant and marine design platform from Hexagon, formerly Intergraph SmartMarine 3D.
High Speed Craft Code: IMO HSC Code addressing safety standards for craft operating above conventional speed thresholds.
HLES: Hybrid LES turbulence model available in STAR-CCM+ for transient ship flow simulations.
Hold Frame Section Modulus: Bulk carrier side frame requirement governed by IACS UR S12.
Hold Loading Sequence: Bulk carrier loading and unloading pattern constrained by IACS UR S1A.
Hollenbach Method: Resistance prediction method for single and twin screw vessels published by Hollenbach in 1998.
Holtrop-Mennen method: Statistical resistance and powering prediction.
Hot Spot Stress: Structural stress at a fatigue crack initiation site computed per CSR-BC+OT Chapter 9.
HSC Code: International Code of Safety for High-Speed Craft, MSC.97(73), 2000.
Hull Form Generation: Process of producing fair hull surfaces in NAPA, Rhinoceros, Maxsurf Modeler, or DELFTship.
Hull Girder Bending Moment: Vertical and horizontal bending moments governed by IACS UR S11 and S11A.
Hull Surf Studio: Hull surface modeling package marketed for early-stage naval architecture design.
HydroD: DNV Sesam preprocessor for hydrostatic, stability, and hydrodynamic analyses.
Hydrostatic curves: Curves of form versus draft.

I

IACS: International Association of Classification Societies, 12 members.
IACS Common Structural Rules: Harmonized rules for bulkers/tankers.
IACS PR: Procedural Requirement issued by IACS, complementing the Unified Requirements.
IACS Recommendation 34: Standard wave data for North Atlantic.
IACS Recommendation 56: Fatigue assessment of ship structures based on spectral methods.
IACS UI: Unified Interpretation issued by IACS clarifying application of statutory IMO instruments.
IACS UR A: Anchoring equipment Unified Requirements covering equipment number and chain cable.
IACS UR B: Boundary requirements Unified Requirements addressing watertight and weathertight integrity.
IACS UR C: Containers and securing arrangements Unified Requirements.
IACS UR E: Electrical Unified Requirements including E22 software-based systems and E26-E27 cyber security.
IACS UR I: Unified Requirements for Polar Class ships covering structural and machinery design.
IACS UR M: Machinery Unified Requirements covering main engines, auxiliaries, and piping systems.
IACS UR P: Pollution prevention Unified Requirements.
IACS UR S: Structures Unified Requirements numbered S1 through S37 covering hull strength topics.
IACS UR S1: Bulk carrier longitudinal strength loading guidance.
IACS UR S11: Unified requirement on longitudinal strength.
IACS UR S11A: Longitudinal strength standard for container ships including whipping and springing.
IACS UR S17: Bulk carrier longitudinal strength in flooded condition.
IACS UR S18: Bulk carrier transverse corrugated bulkhead strength in flooded condition.
IACS UR S21: Unified requirement on hatch cover strength.
IACS UR S21A: Strength of small hatch covers on the exposed fore deck of ships.
IACS UR S23: Implementation of IACS bulk carrier rules.
IACS UR S25: Cargo hold length limitation for bulk carriers.
IACS UR S30: Container ship cargo holds and hatch cover requirements addressing whipping.
IACS UR S33: Design wave loads on oil tanker structures.
IACS UR S34: Functional requirements on load cases for direct strength analysis of oil tankers.
IACS UR S6: Use of steel grades for various hull members in compliance with MARPOL and SOLAS.
IACS UR W: Welding Unified Requirements addressing weld procedures, welder qualification, and consumables.
IACS UR W11: Hull steel grade requirements.
IACS UR Z: Survey Unified Requirements covering periodic and intermediate surveys.
IACS URS6: Use of steel grades for various hull members referenced in CSR-BC+OT.
IBC Code: International Code for the Construction and Equipment of Ships Carrying Dangerous Chemicals in Bulk.
Ice class notation: Class assignment for navigation in ice, often required by flag and port authorities in polar waters.
ICLL: International Convention on Load Lines, 1966, with 1988 Protocol, governing freeboard assignment.
Identification of Critical Areas: CSR-BC+OT screening procedure for fine mesh fatigue analysis.
IGC Code: International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk.
IGF Code: International Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels.
IMDG Code: International Maritime Dangerous Goods Code, mandatory under SOLAS VII Part A.
Immersed Body Method: Numerical technique used in some CFD codes for moving ship geometries.
IMO MSC Circ.1455: Guidelines for the approval of alternatives and equivalents as provided in various IMO instruments.
IMSBC Code: International Maritime Solid Bulk Cargoes Code, mandatory under SOLAS VI/1-1 and VII/7-1.
Inclining experiment: Test determining KG per IS Code 2008.
Inertia Coupling: Cross terms in the ship's mass matrix used in coupled heave-pitch-roll motion analysis.
Initial stability: Stability range described by GM at small heel.
Inland Vessel Notation: Class notation issued by IACS societies for vessels operating on rivers and lakes.
Intact Stability Code: IMO 2008 IS Code defining stability criteria implemented in NAPA, GHS, and Maxsurf Stability.
Integration Point: Numerical quadrature location in finite elements where stresses are evaluated in Abaqus and Ansys.
Intergraph SmartMarine 3D: 3D ship design platform from Intergraph, now Hexagon Smart3D.
International Towing Tank Conference: ITTC, voluntary association of model basins that publishes standardized procedures since 1933.
IRS: Indian Register of Shipping.
IRS Rules and Regulations for the Construction and Classification of Steel Ships: IRS principal class rule set.
IRS-SHIPS: IRS computer program suite for rule-based hull and machinery scantling checks.