Extended Operational and Trade Vocabulary

Hull Integrity Monitoring and Strain Gauges glossary

The hull-monitoring vocabulary: hull-stress monitoring systems and their integration with bridge and power-management suites, the ABS HM-1 class notation and sensor placement, strain gauges and accelerometers, and the fatigue and slamming-load terms. Grounds each term in the monitoring system or the class notation it belongs to.

230 defined terms.

A

Aanderaa Data Instruments: Norwegian oceanographic instrumentation manufacturer producing wave and current sensors used in marine measurement campaigns.
ABB Ability Marine Pilot: Integrated bridge and vessel performance suite from ABB Marine that can ingest hull monitoring data alongside propulsion and navigation streams.
ABB Marine: Swiss-Swedish marine systems supplier whose offerings include hull stress monitoring integration with ABB automation and power management systems.
ABS Guide for Hull Condition Monitoring Systems: Published guidance from the American Bureau of Shipping setting out requirements for HMS installation, sensors, software, and class notation issuance.
ABS HM-1: ABS hull monitoring class notation covering measurement of hull girder stresses on a limited number of locations.
ABS HM-2: ABS hull monitoring notation extending HM-1 with acceleration and motion measurement for slamming and whipping response.
ABS HM-3: ABS hull monitoring notation adding ice load monitoring channels for ice-class operation.
ABS Real-time Wave (RW): ABS notation for installed wave measurement equipment providing real-time sea state to the bridge.
ABS Smart Vessel FUL: ABS Smart notation tier recognizing fully integrated condition and performance monitoring across hull, machinery, and operations.
Accelerometer: Inertial transducer measuring linear acceleration of hull or superstructure, used for slamming, whipping, springing, and vibration monitoring.
Acoustic Emission (AE) Testing: Passive non-destructive technique that detects elastic waves from crack growth or yielding in hull plating and welds.
Adhesive Cure: Controlled time and temperature step in strain gauge installation during which the bonding adhesive develops full mechanical strength.
Adhesive M-Bond AE-10: Two-part epoxy adhesive from Vishay Micro-Measurements used for long-term bonding of foil strain gauges to steel.
AE Sensor Pico: Compact piezoelectric acoustic emission transducer in the Mistras Group sensor family used for localized monitoring.
AE Sensor R15a: Resonant 150 kHz piezoelectric acoustic emission sensor from Mistras Group widely used in structural integrity monitoring.
AE Sensor R30a: Resonant 300 kHz piezoelectric acoustic emission sensor from Mistras Group used where higher frequency content is required.
Aft Peak Tank Strain: Localized strain measurement around the aft peak structure used to monitor stern slamming and propeller-induced vibration loads.
Alarm Limit: Configured threshold in hull stress monitoring software that triggers a visual or audible warning when measured stress or acceleration exceeds set bounds.
Allowable Stress: Class-society-derived permissible stress used as the reference for HMS alarm thresholds on hull girder bending and shear.
Amplifier Bridge Conditioner: Signal conditioning unit that supplies excitation to a Wheatstone bridge and amplifies the millivolt strain gauge output.
Analog-to-Digital Converter: Component within a strain interrogator or data acquisition unit that digitizes conditioned analog signals for processing and logging.
Anchor Handling Trial: Sea trial procedure verifying the ability of an anchor handling vessel to deploy, hold, and recover anchors under specified conditions.
Annual Hold Inspection: Class-required yearly survey of bulk carrier cargo holds checking corrosion, cracking, and coating condition.
Applied Weather Technology (AWT): A historical weather routing service provider whose Bon Voyage System product was later acquired by Sperry Marine and then sold on through subsequent owners.
Approval Letter: Written confirmation from an oil major's vetting department that a named vessel is cleared for a specific voyage, berth, or term period.
Avitas Systems: Inspection services provider, originating from GE Ventures, that has used autonomous platforms including drones for asset inspection.

B

Bending Moment Diagram: Plot of longitudinal bending moment along ship length used to interpret hull girder stress measurements.
BLH Nobel: Force and weighing instrumentation brand with a heritage in load cells and strain-based measurement, part of the VPG group.
Bollard Pull Trial: Controlled test in which a tug pulls against a load cell anchored to a quayside bollard.
Bon Voyage System (BVS): A long established PC based weather routing and voyage optimization product, currently offered by StormGeo following multiple changes of ownership.
Bottom Plate Strain Gauge: Strain gauge bonded to bottom shell plating to capture loads from bottom slamming and whipping.
Bottom Slamming: Impact of the flat bottom against the sea surface when the forward portion emerges and re-enters during heavy pitching.
Bow Flare Slamming: Forward impact accelerations, particularly severe in CSS Annex 13 forward-zone factors.
Bow Plate Transverse Strain: Strain measurement across the bow plating used to characterize slamming pressure response.
Bow Slamming: General term for impulsive bow impact loads, particularly significant on VLCC and Capesize hulls in head seas.
Bragg Wavelength: Specific reflected wavelength from a fiber Bragg grating, which shifts in proportion to strain and temperature.
Bridge HMI: Human machine interface on the navigation bridge presenting hull monitoring data to the master and officers.
Bridge Integration: Connection of satellite communications equipment to ECDIS, radar, and VDR systems on the navigation bridge.
Bruel and Kjaer: Danish measurement instrumentation brand, part of Hottinger Bruel and Kjaer (HBK), known for accelerometers and acoustic transducers.
Bulk Carrier Booklet of Loading Conditions: Required onboard document listing approved loading patterns and corresponding still-water bending and shear values.
Bureau Veritas (BV): French classification society, founded 1828, IACS founding member.
BV HSM: Bureau Veritas additional class notation for installed hull stress monitoring systems.

C

Cable Gland: Mechanical fitting that secures a cable entering an enclosure and provides strain relief, sealing, and bonding.
Calibration Shunt: Precision resistor switched across a strain gauge bridge arm to generate a known simulated strain for verification.
Cargo Hold Girder Strain: Strain measurement on transverse or longitudinal girders within bulk carrier holds used to monitor cargo-induced loads.
Cargo Hold Inspection: Survey of internal hold structure for corrosion, cracking, and coating breakdown.
Cargo Tank Inspection: Survey of tanker cargo tank internals including longitudinals, web frames, and bulkheads.
CCS HSM: Hull stress monitoring class notation issued by China Classification Society.
Class Notation: Class society designation reflecting compliance with construction and equipment rules incorporated into SOLAS by reference.
ClassNK: Nippon Kaiji Kyokai, Japanese classification society and IACS member, founded 1899.
ClassNK Hull Monitoring System Guidance Note: Published ClassNK document setting out recommended practice for HMS design, installation, and operation.
ClassNK MHM: ClassNK Machinery and Hull Monitoring related notation framework.
ClassNK MRV Reporting Tool: ClassNK software supporting EU MRV emissions reporting from operational data.
Compact Reconfigurable IO (cRIO): National Instruments distributed data acquisition platform combining controller, FPGA, and modular IO for strain and vibration measurement.
CompactRIO NI-9237: Bridge-based analog input module from National Instruments designed for strain gauge measurement on the cRIO platform.
Container Lashing Bridge Stress: Stress measured on lashing bridge structures supporting deck container stacks.
Container Ship Hull Torsion: Significant warping moment on open-deck container ships in oblique seas, addressed by IACS UR S11 and S33.
Container Stack Monitoring: Measurement of forces or strains on deck container stacks to limit overturning moment and lashing failure risk.
Corrosion Monitoring: Periodic or continuous assessment of plate thickness loss using ultrasonic gauging or gravimetric coupons.
Cruise Ship Whipping: Transient global vibration of large passenger ship hulls following slamming or ice impact, relevant to onboard comfort.
CSI Bridge Conditioner: Channel strain signal conditioning unit used in fielded measurement systems.

D

Damping Ratio: Fraction of critical damping used in seakeeping and structural dynamic analyses.
Data Acquisition Rate: Sampling frequency of a hull monitoring system, typically 100 to 200 Hz for capturing whipping content.
Deck Longitudinal Strain Gauge: Strain gauge bonded to a deck longitudinal stiffener at midship to capture hull girder bending response.
Deflection Monitoring: Measurement of relative displacement between hull points to assess global deformation under load.
Diver Hull Cleaning: Underwater cleaning of hull surfaces by trained divers using brushes or rotary tools.
DNV: Det Norske Veritas (DNV); IACS member classification society.
DNV HMON: DNV class notation for installed hull monitoring systems.
DNV HMON-1: Partial hull monitoring tier of the DNV HMON notation.
DNV HMON-2: Full hull monitoring tier of the DNV HMON notation covering stresses, accelerations, and environmental data.
DNV ShipX: DNV hydrodynamic and structural analysis software suite used in design and load assessment.
DNV WaveWatch: DNV branded wave information service used for routing and operational decision support.
Drone Hull Inspection: Use of aerial unmanned vehicles for close-up visual inspection of hull structures.
DTN: Weather services provider offering marine forecasts and routing guidance to commercial fleets.

E

ECDIS overlay: overlay of port boundaries and traffic patterns on ECDIS.
ECMWF ERA5: Global atmospheric and ocean reanalysis dataset produced by the European Centre for Medium-Range Weather Forecasts.
Electrical Strain Gauge: Resistive sensor whose change in electrical resistance corresponds to mechanical strain.
Electromagnetic Immunity: Property of fiber optic sensing systems to be unaffected by electromagnetic interference.
Endevco: American transducer brand within the Meggitt group, known for piezoelectric accelerometers and pressure sensors.
Endevco 6213: Endevco piezoelectric pressure transducer model historically used in sloshing and impact studies.
Endurance Trial: Sea trial verifying sustained operation of propulsion and auxiliary systems over an extended period at service load.
Eniram: Wartsila fleet performance and trim optimization platform.
ERA5 Reanalysis: Hourly global reanalysis of atmospheric and wave parameters published by ECMWF.

F

Femtoscan: Fiber optic sensing technology brand offering interrogators and sensors for structural monitoring applications.
Fiber Bragg Grating (FBG): Periodic refractive index modulation written into an optical fiber that reflects a narrow wavelength shifting with strain or temperature.
Fiber Optic Interrogator: Instrument that launches light into a fiber sensor array and measures reflected wavelengths to derive strain and temperature.
Foil Strain Gauge: Resistive strain gauge formed by a thin patterned metal foil bonded on a polymer backing.
Full Bridge Configuration: Wheatstone bridge arrangement using four active strain gauges providing maximum sensitivity and temperature compensation.
Furuno WR-2120: X-band wave radar product from Furuno used to estimate wave height and direction.

G

Gauge Factor: Ratio of fractional resistance change to applied strain in a strain gauge, typically near 2.0 for metallic foil types.
Green Sea Loads: Loads from solid water boarding the deck during heavy seas, considered in HMS deck and forecastle design.
GTT Sloshing Model Basin: Sloshing test facility operated by Gaztransport and Technigaz in Marseille for membrane LNG containment studies.
Gyroscope: Inertial sensor measuring angular rate, combined with accelerometers within an IMU.

H

Half Bridge Configuration: Wheatstone bridge arrangement with two active strain gauges providing bending or temperature compensated measurements.
Hawke Cable Gland: Brand of marine and hazardous area cable glands used on instrumentation enclosures.
HBK: Hottinger Bruel and Kjaer, the combined measurement brand within Spectris encompassing HBM and Bruel and Kjaer product lines.
HBM: Hottinger Baldwin Messtechnik, German measurement technology company, now part of HBK within Spectris.
HBM 1-LM11/120: HBM resistive strain gauge with 120 ohm nominal resistance from the LM series.
HBM 1-LY11-3/120: HBM single grid foil strain gauge with 3 mm grid and 120 ohm resistance.
HBM 1-LY18-3/120: HBM single grid foil strain gauge variant with 3 mm grid and 120 ohm resistance for general structural testing.
HBM MX1615B: HBM QuantumX bridge amplifier module with 16 channels designed for strain gauge measurement.
HBM PMX: HBM industrial measurement amplifier platform for permanent installations.
HBM QuantumX: HBM modular data acquisition system family supporting strain, temperature, and voltage inputs.
Hindcast Wave Data: Historical wave parameters reconstructed from numerical models for operational and design analysis.
Hippomate Brush: Hull brushing equipment brand used for underwater cleaning operations.
Hogging: Stress condition with the bow and stern lower than the midship.
Honeywell Sensotec: Legacy Honeywell brand for force, pressure, and load measurement transducers.
Hopper Side Tank Crack Monitoring: Targeted inspection or instrumentation of bulk carrier hopper and side tank structures prone to fatigue cracking.
Hottinger Baldwin Messtechnik: Full historical name of HBM, the German strain measurement instrumentation manufacturer.
Hull Condition Monitoring: Broad practice of tracking structural condition including stress, vibration, corrosion, and cracking.
Hull Girder Horizontal Bending Moment (HBM): Bending moment about the vertical axis arising from lateral wave and maneuvering loads.
Hull Girder Torsion Moment (HTM): Twisting moment on the hull, particularly significant for container ships with large deck openings.
Hull Girder Vertical Bending Moment (VBM): Bending moment about the transverse axis combining still water and wave-induced components.
Hull stress monitoring system (HSMS): Strain gauges on deck, used at trial.

I

IACS UR S11: Unified requirement on longitudinal strength.
IACS UR S31: IACS unified requirement covering renewal criteria for hull structural items, including hold flooding scenarios for bulk carriers.
IACS UR S33: Design wave loads on oil tanker structures.
IACS UR S35: IACS unified requirement for operational loading information on container ships.
Ice Belt Strain: Strain measurement on the reinforced ice belt plating of ice-class vessels.
Ice Load Panel: Instrumented plate panel used to measure ice contact loads on hull plating.
Ice Slamming: Impulsive contact between hull and ice features during navigation in ice covered waters.
ICEMOS: Ice load monitoring product line associated with the Light Structures SENSFIB family.
Inertial Measurement Unit (IMU): Integrated sensor package combining accelerometers and gyroscopes to provide motion and attitude data.
Integrated Bridge Solution (IBS): Architecture in which monitoring and navigation systems share displays and data on the bridge.
Intrinsic Safety: Property of equipment that limits available energy below ignition thresholds, supporting use of fiber sensors in hazardous zones.
iXBlue: French manufacturer of inertial navigation systems and motion sensors used in marine survey and naval applications.

J

J2/N2A Rosette: Vishay Micro-Measurements designation pattern for two-element 90 degree rectangular rosette strain gauges.
Junction box: Enclosure terminating cables on instruments and motors, with IP rating per zone classification.

K

Kistler: Swiss measurement technology company manufacturing piezoelectric accelerometers, force, and pressure sensors.
Kistler 7261C: Kistler piezoelectric pressure sensor model historically used in sloshing and impact pressure measurement.
Kongsberg Hull Stress Monitoring System: Hull monitoring offering from Kongsberg Maritime integrated with its bridge and automation systems.
Kongsberg Maritime: Norwegian supplier of bridge, automation and dynamic positioning systems.
Kongsberg MRU 5: Motion reference unit model from Kongsberg providing pitch, roll, and heave data.
Kongsberg MRU 6: Higher specification motion reference unit in the Kongsberg Seatex MRU family.
KR HSM: Hull stress monitoring class notation issued by Korean Register of Shipping.
Kyowa Electronic Instruments: Japanese strain gauge and measurement amplifier manufacturer.
Kyowa KFG-5-120-D16-11N: Kyowa foil strain gauge product code denoting 5 mm grid, 120 ohm, and standard backing.

L

Lashing Stress: Force in container lashing rods and turnbuckles induced by ship motions, monitored to limit overload.
Leadwire Termination: Soldered or crimped connection joining a strain gauge to its instrumentation cable.
Light Structures: Norwegian supplier of fiber optic hull monitoring systems under the SENSFIB brand.
Light Structures SENSFIB: Fiber Bragg grating based hull stress monitoring product family from Light Structures.
Lloyd's Register Hull Monitoring: Notation framework from Lloyd's Register covering installed hull monitoring systems.
LNG Membrane Stress: Strain in the metallic membrane of containment systems on LNG carriers under thermal and mechanical loads.
LR HMS: Lloyd's Register hull monitoring system class notation designation.

M

Maersk Drone Inspection Service: Drone-based vessel inspection program associated with the Maersk group.
Magnetostrictive Sensor: Sensor exploiting strain-induced changes in magnetic properties for displacement or force measurement.
Maneuvering Trial: Sea trial program assessing turning, course keeping, and stopping performance.
Master Maritime Approval: Approval letter from a classification society confirming HMS suitability for an assigned notation.
MEMS Accelerometer: Microelectromechanical systems device measuring acceleration using micromachined silicon proof masses.
Metal Foil Strain Gauge: Strain gauge using a patterned metal foil grid on a polymer backing.
Micron Optics: Fiber optic sensing instrumentation brand, later part of Luna Innovations, supplying FBG interrogators.
Midship Section Modulus: Geometric property of the hull cross section relating bending moment to bending stress at the deck or bottom.
MIROS Wave Radar: Norwegian-supplied wave radar system for sea state measurement.
Mistras Group: Provider of acoustic emission sensors, instrumentation, and structural health monitoring services.
Motion Reference Unit (MRU): Sensor measuring vessel pitch, roll, heave, and related motions, often integrated with HMS.

N

NAPA Voyage Optimization: A weather routing and speed profile optimization product from NAPA used to plan and execute fuel efficient voyages.
National Instruments PXI: Modular instrumentation platform supporting strain and vibration measurement cards.
NK HSM: ClassNK hull stress monitoring class notation.
NOAA WaveWatch III: Third-generation spectral wave model developed at NOAA and widely used for global wave forecasting.
Noise Floor: Lowest level of measurable signal above instrumentation noise in a strain or vibration channel.

O

OceanWaveS: German company supplying the WaMoS wave radar systems.
OMEGA Engineering: American instrumentation supplier offering strain gauges, load cells, and signal conditioning.
Operational Loading Information: Onboard documentation required under IACS UR S35 describing loading and stress assessment for container ships.

P

PCB 333B30: PCB Piezotronics general purpose ICP accelerometer model.
PCB 356B18: PCB Piezotronics triaxial ICP accelerometer model used for low-level structural measurement.
PCB 393B12: PCB Piezotronics seismic ICP accelerometer model designed for low-frequency, high-sensitivity measurements.
PCB 393B31: PCB Piezotronics seismic ICP accelerometer model with higher sensitivity for low-level ambient vibration.
PCB Piezotronics: American manufacturer of piezoelectric accelerometers, force, and pressure sensors.
Pico AE Sensor: Small footprint acoustic emission transducer from Mistras Group.
Piezoelectric Accelerometer: Accelerometer that generates charge proportional to acceleration through stressed piezoelectric crystals.
Piezoelectric Polymer Film: Sensing element using polymers such as PVDF that develop charge under mechanical strain.
Polar Code: Adopted under SOLAS XIV and MARPOL; complements Article 234 jurisdiction.
PVDF Sensor: Sensor using polyvinylidene fluoride piezoelectric film for dynamic strain and pressure measurement.

Q

QuantumX MX1615B: Sixteen channel strain gauge amplifier module from HBM within the QuantumX system family.
Quarter Bridge Configuration: Wheatstone bridge arrangement with one active strain gauge and three fixed resistors used in many basic strain measurements.

R

Reanalysis Wave Data: Wave parameters produced by running modern numerical models over historical periods with assimilated observations.
Resistance Strain Gauge: General term for any strain gauge based on change of electrical resistance under strain.
Resonant Frequency Sensor: Acoustic emission sensor designed to exhibit peak sensitivity at a specific frequency such as 150 or 300 kHz.
Rosette Strain Gauge: Strain gauge with multiple grids at fixed angles used to determine principal strains.

S

Sagging: Stress condition with the midship lower than the ends.
Sea trial: Trials at sea testing speed, maneuvering, vibration, noise, and machinery performance.
SENSFIB Console: Bridge console display in the Light Structures SENSFIB family presenting hull monitoring information.
SENSFIB Hull Stress: Hull stress monitoring product line within the Light Structures SENSFIB portfolio.
SENSFIB IBS: Light Structures SENSFIB integrated bridge solution version designed for integration with the navigation bridge.
SENSFIB ICEMOS: Light Structures SENSFIB product variant focused on ice load monitoring.
Shunt Calibration: Verification technique using a precision resistor to simulate a known strain change across the bridge.
Slamming Pressure: Impulsive pressure on hull plating during impact with the sea surface, often measured by piezoelectric transducers.
Sloshing Impact Pressure: Transient pressure on tank walls from liquid cargo movement, measured during sloshing model tests and onboard.
Smart Fibres: United Kingdom based supplier of fiber Bragg grating sensors and interrogators.
SoMat eDAQ: Mobile data acquisition system family historically associated with HBM for field structural measurement.
Speed Trial: Sea trial measuring vessel speed at defined power settings, typically on a measured mile course.
Sperry Marine MRU: Motion reference unit offering from Sperry Marine.
SPOS: Ship Performance Optimization System voyage routing software.
Springing Stress: Continuous resonant vibration of the hull girder driven by waves at frequencies near the lowest vertical bending mode.
Stack Stress Monitoring: Measurement of forces or accelerations on container stacks to manage lashing and stack stability.
Stern Slamming: Impact loading on the stern, particularly relevant to twin-screw vessels with flat stern sections.
StormGeo BVS: StormGeo's onboard voyage planning software derived from the Bon Voyage System lineage.
Strain Foil Resistive Gauge: Resistive strain gauge built on a thin metallic foil grid.
Strain Gauge Adhesive: Bonding agent such as cyanoacrylate or epoxy used to attach strain gauges to structural surfaces.
Strain Gauge Installation: Process of preparing the surface, bonding the gauge, terminating leadwires, and applying protection.
Surface preparation: Mechanical or chemical treatment of a substrate before coating application.

T

Tanker Longitudinal Strain Gauge: Strain gauge installed on tanker hull longitudinals to capture local and global stress.
TML: Tokyo Measuring Instruments Laboratory, common branding for Tokyo Sokki Kenkyujo, a Japanese strain gauge and instrumentation manufacturer.
TML FLA-5-11: Tokyo Sokki Kenkyujo foil strain gauge product code with 5 mm grid for general structural measurement.
Tokyo Sokki Kenkyujo: Japanese measurement instrumentation manufacturer producing foil strain gauges and amplifiers under the TML brand.
Triaxial Accelerometer: Accelerometer measuring linear acceleration along three orthogonal axes within a single housing.
Twist-Lock Stress: Force in container twist-lock fittings induced by stack motion and lashing loads.

U

Ultrasonic Thickness Gauging: Non-destructive measurement of plate thickness using ultrasonic pulse echo techniques for corrosion assessment.
Underdeck Longitudinal Gauge: Strain gauge bonded to a longitudinal stiffener beneath the main deck for hull girder bending measurement.

V

Vibrating Wire Strain Gauge: Strain gauge employing a tensioned wire whose resonant frequency varies with applied strain.
Vishay Measurements Group: Historical name associated with the Vishay strain gauge and instrumentation business.
Vishay Micro-Measurements: American strain gauge and bonding accessories manufacturer within the Vishay Precision Group.
VLCC Bow Slamming: Bow slamming event on a very large crude carrier in heavy head seas.

W

WaMoS II: OceanWaveS marine X-band wave radar system measuring directional wave spectra.
WaMoS III: OceanWaveS successor wave radar system providing enhanced wave measurement capability.
Wartsila: supplier of port-area thrusters, automation, and LNG bunkering systems.
Waterproof Coating: Protective layer applied over an installed strain gauge to seal it against moisture ingress.
Wave Buoy: Floating instrument measuring wave height, period, and direction at a fixed location.
Wave Hindcast: Retrospective wave data used in salvage planning and award argument.
Wave Radar: Radar system that measures sea surface elevation and derives wave parameters from backscatter patterns.
WAVEWATCH III: NOAA third-generation wave model.
WeatherNews (WNI): Japanese weather services company providing marine forecasts and voyage routing.
Web Frame Crack: Fatigue crack initiating in tanker or bulker transverse web frames at high stress locations.
Wheatstone Bridge: Resistive bridge circuit used to convert small resistance changes from strain gauges into measurable voltages.
Whipping Stress: Transient hull girder vibratory stress following an impulsive load such as slamming.
Wing Tank Longitudinal: Longitudinal stiffener in tanker wing tanks subject to local and global stress.
Wiska Cable Gland: German brand of cable glands used in marine instrumentation enclosures.

X

X-Band Wave Radar: Marine radar operating in the 9 GHz region used as the basis for systems such as WaMoS and Furuno WR-2120.
XY Rosette: Two-element strain gauge rosette with grids oriented at 90 degrees for biaxial strain measurement.

Z

Zero Drift: Slow change in the unloaded baseline output of a strain gauge channel, addressed by periodic re-zeroing and temperature compensation.