Extended Operational and Trade Vocabulary

Tugs and Towage Industry glossary

The towage-industry vocabulary: the towage operators and their parents (Svitzer under Maersk), bollard-pull certification, escort-towage assignments by size class, and the towing-arrangement terms. Grounds each term in the towage company or the harbor-escort operation it belongs to, complementing the tug-operations section.

263 defined terms.

Showing 250 on this page (page 1 of 2).

A

A.P. Moller Maersk: Danish shipping conglomerate that owns Svitzer, one of the world's largest harbor towage operators.
ABS Bollard Pull Certificate: Certification issued by the American Bureau of Shipping documenting a tug's static bollard pull under defined test conditions.
Aframax Escort: Escort towage assignment for an Aframax tanker requiring tugs of sufficient bollard pull and indirect steering force.
Aft Lead: Towing arrangement where the working line leads from the tug's stern winch to the assisted vessel.
Air Tugger: Pneumatic deck winch used on tugs and barges to handle messenger lines and stoppers.
ALP Defender: ALP Maritime Services ocean-going anchor handling tug of the ALP Future-class series.
ALP Forward: ALP Maritime Services Future-class ocean tug operating from Den Helder for long-distance towage.
ALP Future Class: Series of four ocean tugs built for ALP Maritime Services by Niigata Shipbuilding, each rated above 300 tonnes bollard pull.
ALP Keeper: ALP Maritime Services Future-class ocean tug for ultra-long-distance towage operations.
ALP Maritime Services: Dutch ocean towage specialist headquartered in Den Helder, owned by Teekay Offshore and later Altera Infrastructure.
ALP Striker: Lead vessel of the ALP Future-class series rated at approximately 309 tonnes bollard pull.
ALP Sweeper: ALP Maritime Services Future-class ocean tug used for rig moves and project towage.
Alphabridge: Wartsila integrated bridge concept frequently fitted on modern harbor and escort tugs.
Anchor Handling: Deployment and recovery of ground tackle, beach gear, and mooring spreads.
Anchor handling tug supply vessel: Offshore support vessel class used to set moorings for floating tidal, wave, and floating solar platforms.
Antwerp Towage: Boluda-owned harbor towage operator serving the Port of Antwerp.
Aquamaster: Original Rauma-Repola azimuth thruster line, later Rolls-Royce and now Kongsberg, widely used on tugs and OSVs.
ART Tug: Robert Allan Ltd Advanced Rotor Tug design with three azimuth thrusters in a triangular arrangement.
Articulated tug barge: ATB unit common in US coastal trade.
ASD tug: Azimuth Stern Drive tug with two stern-mounted azimuth thrusters.
ASD-E Tug: Damen designation for hybrid-electric variants of its ASD tug platform.
Astilleros Armon: Spanish shipbuilder in Asturias known for ocean-going tugs and offshore vessels.
Astilleros Gondan: Spanish private yard at Figueras building tugs, ferries, and offshore support vessels.
Astilleros Zamakona: Basque yard at Bilbao and Las Palmas building tugs, fishing vessels, and patrol craft.
ATB: Articulated Tug Barge, integrated unit used in US coastal oil response and lightering.
Azimuth Thruster: Propulsion unit rotating 360 degrees about a vertical axis to direct thrust in any horizontal direction.

B

Backing Plate: Reinforcement plate beneath fittings; checked during structural surveys.
Bayonet Pin: Locking pin used in certain articulated tug barge connection systems.
BHP: Brake horsepower, the power measured at the engine output shaft of a tug's main engine.
Bisso Marine: Louisiana-based US Gulf Coast marine services company providing harbor and inland towage and salvage.
Bitt: Vertical post on deck for securing lines.
Bludworth Coupler: US-designed articulated tug barge coupling system using a pin engaging notches in the barge.
Bogacay Series: Sanmar Shipyards range of compact ASD harbor tugs built in Turkey.
Bollard pull: Tug pulling force in tonnes.
Bollard Pull Certificate: Class society document recording the result of a witnessed bollard pull trial.
Bollard Pull Trial: Controlled test in which a tug pulls against a load cell anchored to a quayside bollard.
Boluda Towage: International towage group based in Valencia, Spain, active in Europe, West Africa, the Americas, and the Middle East.
Boskalis: Dutch dredging and salvage major, parent of SMIT Salvage since 2010.
Bourbon Surf Class: Series of large offshore AHTS vessels built for Bourbon Offshore with high bollard pull.
Bow Staple: Forward fairlead on a harbor tug through which the working line is led during ship handling.
Bow thruster: Transverse-tunnel thruster forward for low-speed maneuvering.
Brake Holding Load: Maximum static load a winch brake can hold without slipping, expressed in tonnes.
Brattvaag: Norwegian winch and deck machinery brand now part of MacGregor and Kongsberg Maritime.
Bridle: Two-leg rope or chain attached to a single point.
Brunvoll: Norwegian manufacturer of tunnel thrusters, azimuth thrusters, and CP propeller systems for offshore vessels.
Bugsier-Reederei: Hamburg-based German towage and salvage operator with operations across North Sea and Baltic ports.
Bukser og Berging: Norwegian towage company headquartered in Oslo providing harbor, escort, and ocean towage services.
Bulwark: Solid extension of the hull plating above the weather deck.

C

Carrousel Tug: Novatug concept with a winch mounted on a rotating ring around the superstructure, allowing 360 degree towline lead.
Cell Fender: Cylindrical rubber fender comprising an inner cell core and front frame used on tug bows and harbor structures.
Centerlead: Towing fairlead positioned on the centerline of the bow or stern.
Christophe de Margerie: Arc7 ice-class LNG carrier whose movements in the Russian Arctic frequently require icebreaking tug escort.
Cintranaval Defcar: Spanish naval architecture firm designing tugs, ferries, and offshore vessels.
Class I Winch: Markey Machinery rendering and recovery winch classification used on North American escort and ship handling tugs.
Classification Society: Organization that develops technical rules and certifies compliance; members of IACS include ABS, BV, CCS, CRS, DNV, IRS, KR, LR, NK, PRS, RINA, and RS.
Cleat: Two-horned fitting around which a line is belayed.
Combi Drive: Schottel propulsion concept combining a cycloidal forward thruster with stern azimuth drives.
Combi Tug: Hybrid tug design integrating azimuth stern drives with a tractor-style forward propulsion arrangement.
Cone Fender: Conical rubber fender used on tug bows and ship-side contact areas.
Controllable Pitch Propeller: Propeller with adjustable blade pitch used on certain conventional and tractor tugs.
Cory Brothers: UK shipping agent and towage operator historically active at British ports.
Coupling System: Mechanical interface between an articulated tug and its barge.
Crowley Maritime: US ocean towage, harbor towage, and logistics operator headquartered in Jacksonville, Florida.
Cycloidal Propeller: Vertical-axis propeller of the Voith Schneider type with cyclically pitching blades.

D

Damen ASD Tug 2810: Damen Shipyards Group standard ASD tug design with a length of 28 meters and beam of 10.43 meters.
Damen ASD Tug 3010: Damen ASD tug standard model of 30 meters in length used widely in harbor towage worldwide.
Damen ASD Tug 3212: Damen ASD tug standard model of 32 meters length and 12 meters beam.
Damen ASD Tug 3413: Damen ASD tug 34 meters in length and 13 meters in beam, used for terminal and escort work.
Damen Modular Tug: Damen tug concept built from standardized modules to permit accelerated delivery and customization.
Damen RSD Tug 2513: 25 m Reverse Stern Drive Damen design symmetrical fore and aft, with twin azimuth thrusters forward.
Damen Shiprepair Brest: Damen ship repair yard in Brest, France, servicing tugs, offshore vessels, and naval ships.
Damen Shipyards Group: Dutch shipbuilder, major supplier of ASD, RSD, ATD, and Stan Tug series.
Deck crane: ship-mounted crane used for self-discharge.
Deep Sea Towing: Towage operation conducted on ocean voyages, typically of unmanned barges, rigs, or dead ships.
DEPCC Winch: Markey Machinery double-drum electric escort winch series fitted to escort tugs.
Direct Mode: Escort tug operation pulling along the line of the towline, generating force primarily from propeller thrust.
DMT Marine Equipment: Romanian deck machinery manufacturer supplying winches to tugs and offshore vessels.
DNV Escort Notation: Class notation issued by DNV certifying compliance with escort tug performance requirements.
Double Drum Winch: Towing winch with two independently controlled drums permitting simultaneous bow and stern operations.

E

ECDIS: Electronic Chart Display and Information System per IMO MSC.232(82).
Edda Towage: Dutch tug operator based at Den Helder serving North Sea ports and offshore industry.
Electric Tug: Battery-electric harbor tug such as the Damen RSD-E Tug 2513 in service at the Port of Auckland.
Emergency Release: Mechanism on a towing winch or hook permitting rapid disconnection of the line under load.
Endurance: Extended duration variant of the Kongsberg HUGIN AUV with lithium polymer batteries for very long survey missions.
EnerCon Tug: Robert Allan Ltd design designation for high-endurance terminal tugs.
Escort Notation: Class notation indicating that a tug is certified for high-speed escort towage of tankers.
Escort Tug: High-performance tug providing braking/steering escort to laden tankers.
Escort Winch: Render-recovery winch specified for escort duty with high dynamic performance.
Eyeplate: Welded steel plate with an eye used for attaching shackles on tug decks.

F

Fairlead: Fitting that leads a rope in the desired direction without chafe.
Fairplay Towage: German towage operator headquartered in Hamburg with operations across European ports.
Far Sapphire: Solstad Offshore anchor handling tug supply vessel.
Far Senator: Solstad Offshore AHTS vessel of the Senator class.
Far Sky: Solstad Offshore AHTS vessel.
Far Statesman: Solstad Offshore AHTS vessel of the Statesman class.
Farstad Shipping: Norwegian offshore vessel operator that merged with Solstad and Deep Sea Supply in 2017.
Fendering: Combination of fenders fitted around a tug's hull to absorb impact during ship contact.
FiFi: Fire-fighting capability classification one, two, or three for salvage and support tugs.
FiFi Class: Classification of firefighting capability based on monitor throughput and pump capacity.
Floating storage and regasification unit: Full term for FSRU, a vessel converted or built to receive LNG cargoes and regasify them for sendout to shore.
Forecastle: Forward part of the upper deck; forward crew accommodation.
Foss Maritime: US Pacific Northwest tug and barge operator founded in 1889 in Tacoma, Washington.
Free Running Speed: Maximum sustained speed of a tug in calm water without a tow.
Frontier-Kemper: US engineering firm associated with shaft and tunnel works whose name is sometimes cross-referenced with marine fendering supply.

G

Gantry Winch: Towing winch mounted on raised structural framework to optimize lead angles.
Gas-free certificate: Certificate before hot work in tanks.
General Service Tug: Tug suitable for harbor, coastal, and limited ocean work without specialized escort or salvage equipment.
GES Towing: General Estuarial Services-derived towage operations in major estuaries.
Glosten: Seattle-based naval architecture and marine engineering firm with extensive tug and ATB design experience.
Goliath Towage: Belgian-headquartered tug operator active in Antwerp and other Benelux ports.
Gondan Shipbuilding: Astilleros Gondan, Spanish builder of escort and terminal tugs.
Gross Tonnage: GT, measure of overall internal volume, determinant of statutory certification thresholds.

H

Harbor Tug: Tug for berthing and port maneuvers.
Harken: Marine hardware brand whose deck fittings sometimes appear on smaller tugs and pilot launches.
Hawser: Heavy rope or cable for mooring or towing.
High Holding Power: Anchor characteristic relevant to AHTS work, certified by class society type approval.
Holland Roer: Common spelling reference for steering rudder mountings in classification surveys.
Hull Form: Underwater shape of a tug determining its hydrodynamic performance in direct and indirect modes.
Hybrid Tug: Tug with combined diesel-mechanical and battery-electric propulsion.
Hydrodynamic Lift: Lateral force generated by a tug's hull when sailing at an angle to the tow line during indirect escort.

I

IHC Hytop: Royal IHC subsidiary supplying tow and anchor handling deck equipment.
IJmuiden: Dutch port at the entrance to the North Sea Canal, base for several Dutch towage operators including Iskes.
Indirect Mode: Escort technique in which the tug presents its hull at an angle to the flow, generating hydrodynamic lift on a towline ahead of the assisted ship, typically at 6 to 12 knots.
Inland Towing: Towage of barges on rivers and inland waterways, especially extensive on the US inland river system.
Integrated Tug Barge: Rigidly connected tug and barge unit operated as a single vessel.
Intercon: International Construction Equipment, US manufacturer of articulated tug barge coupling systems.
Iskes Towage and Salvage: Dutch family-owned towage and salvage operator based in IJmuiden.

J

JAK Coupler: Japanese-origin articulated tug barge coupling system designed by Tokyo Kisen-derived engineering.
JBS Sociedade SA: Portuguese towage operator providing harbor towage services at Portuguese ports.
Jones Act: US cabotage law restricting domestic offshore trades to US vessels.
JonRie InterTech: New Jersey-based US manufacturer of deck machinery and towing winches for tugs and workboats.

K

Karmøy Winch: Norwegian deck equipment manufacturer producing winches used on tugs and offshore vessels.
Karmsund Maritime: Norwegian maritime industrial site historically housing shipyards on the Karmsund.
Keppel Smit Towage: Singapore-based joint venture providing harbor towage in Southeast Asia.
Kongsberg Maritime: Norwegian supplier of bridge, automation and dynamic positioning systems.
KORT nozzle: Accelerating ducted-propeller nozzle.
KOTUG: Dutch towage company operating harbor, ocean, and emergency response tugs.
Kotug Canada: Canadian harbor towage operator within the Kotug group.
KOTUG International: Dutch towage group operating in Europe and other regions.
Kotug Smit Towage: Joint venture between Kotug and Smit acquired by Boluda Towage in 2019.

L

Lambert Brothers: Historic British towage interest associated with London river towage.
Length overall: Greatest length of the vessel.
Les Abeilles: French ocean salvage and emergency towage operator headquartered in Brest, now part of Boluda Marine France.
Les Abeilles International: International salvage and ocean towage subsidiary of the Les Abeilles group.
Light Displacement: Vessel weight in lightship condition; basis for draft calculations.
Line Boat: Small workboat used to run lines from a ship to a quay or buoy, often working in conjunction with tugs.
Lloyd's Open Form: Standard salvage contract, current edition LOF 2020 with SCOPIC 2020.
Lloyd's Register Escort Tug: LR class notation indicating a tug certified for escort duties.
Long Towing Bridle: Bridle assembly used on long-distance ocean tows.
Lurssen: German shipbuilder, FAC and corvettes for export.
Lutgens and Reimers: Hamburg-based German towage company providing harbor services on the Elbe.

M

MacGregor: Common type of folding steel hatch cover.
Manchester Ship Canal Tugs: Specialist tugs deployed on the UK Manchester Ship Canal for restricted-water assistance.
Markey Machinery: Seattle-based US winch manufacturer particularly known for its render-recover escort winches.
McAllister Towing: US East Coast harbor towage operator.
Modular Tug: Tug constructed from prefabricated modules, often using Damen's modular hull concept.
Mooring master: pilot specialized in offshore single-point mooring operations.
Moran Towing: US East Coast towage operator founded in 1860 in New York City.
MTS: Multraship Towage and Salvage abbreviation used in fleet identification.
Multraship: Netherlands-based towage and salvage operator.
Multraship Multratug: Series designation for many of the Multraship-owned harbor and terminal tugs.
Multraship Workships: Multraship division focused on offshore workship and standby vessel services.

N

Naval Architect: Engineer specializing in ship design, often RINA-qualified.
NGL Marine: Naval architecture firm associated with US-built workboat and tug projects.
Notch Tug: ATB tug shaped to fit a stern notch in its barge for rigid or articulated coupling.
Novatug: Dutch developer of the Carrousel Rave Tug concept with Voith Schneider propulsion.

O

Ocean Tug: Tug certified and equipped for unrestricted ocean towage.
Oil Rig Support: Towage and supply services provided to mobile offshore drilling units.
Operational Limit: Class-defined sea state or wind range within which a tug is permitted to perform escort or salvage operations.
Overall Beam: Maximum breadth of a tug measured across its hull.

P

Pacific Hickory: Large ocean tug operated by ALP Maritime Services, one of the most powerful ocean tugs in service.
Pad Eye: Welded plate with hole forming a lashing point.
Pendant Wire: Short wire between anchor and surface buoy or workboat.
Petersen and Alpers: Hamburg-based shipping and towage company with historic links to German port services.
Plimsoll Brattvaag: Historical naming combination referring to Brattvaag deck machinery brand.
Plug Mode: Escort technique in which the tug acts as a brake at the stern of the tanker.
Pneumatic Fender: Air-filled rubber fender, typically Yokohama-style, deployed between assisted vessel and quay.
Powered Indirect Mode: Variant of indirect mode in which the tug applies engine thrust to enhance steering force.
Project Cargo Towage: Towage of barges loaded with heavy lift and oversize cargoes between project sites.
PSA Marine: Singapore-based subsidiary of PSA International providing harbor towage and pilotage.
Pulse Tug: Damen branding for fully electric harbor tug variants.
Pusnes: Norwegian deck machinery and mooring equipment manufacturer now part of MacGregor.

R

RAmpage: Robert Allan Ltd tug design for compact harbor and terminal operations.
RAmparts: Robert Allan Ltd series of ASD harbor tugs widely built in shipyards worldwide.
RApport: Robert Allan ASD tug design.
RAscal: Robert Allan Ltd small harbor tug and workboat design.
RAstar: Robert Allan Ltd escort and harbor tug series featuring a sponsoned hull form.
RAve: Robert Allan Ltd Advanced Rotor Tug ART design designation.
RAW Tug: Robert Allan Ltd workboat-class tug design.
Reinauer Transportation: US East Coast tug and ATB operator based in Staten Island, New York.
REMOLCANOSA: Remolques Maritimos SA, Spanish towage operator headquartered in A Coruña.
Render Mode: Winch control mode in which line is paid out automatically when load exceeds a set value.
Reverse Stern Drive Tug: Damen RSD design featuring forward azimuth thrusters and a stern bow staple.
Reverse Tractor Tug: Tug operated stern-first when working, opposite of an ASD configuration.
Reyser: Spanish towage operator headquartered in Barcelona providing services at multiple Spanish ports.
RINA Escort Notation: Class notation issued by RINA certifying compliance with escort tug requirements.
Riverstone: US private equity firm whose maritime investments have included PSA Marine-related transactions.
Robert Allan Ltd: Canadian naval architecture firm in Vancouver specializing in tug design.
Rolls-Royce Commercial Marine: Former marine division of Rolls-Royce supplying azimuth thrusters and propulsion to tugs, divested to Kongsberg Maritime in 2019.
Rotor Tug: Multi-thruster tug design developed under the Kooren and Kotug brands featuring three azimuth thrusters.
Round turn: Single complete turn of a rope around a post.

S

Saam Towage: Latin American and North American towage division of Chilean Sociedad Matriz SAAM.
Saam Towage North America: Canadian and US operations of Saam Towage covering ports including Vancouver and Halifax.
Sailing Trial: Sea trial during which a new tug demonstrates speed, maneuverability, and bollard pull.
Salvage: Recovery of a vessel or cargo from peril at sea.
Salvage Master: Senior salvor in charge of on-scene operations and contract delivery.
Salvage Standby: Service in which a tug remains on station to provide emergency response if required.
Sanmar Shipyards: Turkish shipyard building Robert Allan licensed designs.
Schottel: thruster manufacturer used on tugs and self-propelled barges.
Schottel Combi Drive: Schottel propulsion arrangement combining different thruster types in a single tug.
Schottel Rudder Propeller: Schottel azimuthing rudder propeller branded SRP, widely used on ASD tugs.
Seakeeping: Ability of a tug to maintain operational performance in waves and swell.
Service Speed: Speed used in CSS Annex 13 acceleration calculations; standard values for ships up to 24 knots.
ShibataFenderTeam: German fender manufacturer producing cell, cone, super arch, and pneumatic fenders.
Ship Assist: Towage service of guiding ships into and out of berths.
Skeg: Fixed longitudinal fin on the underside of an escort tug used to generate side force in indirect mode.
Smit Cyclone: Smit Salvage operated ocean tug with bollard pull suited to deep sea salvage.
Smit Hunter: Smit International ocean tug used for long-distance towage and salvage.
Smit International: Dutch towage and salvage company headquartered in Rotterdam, now Boskalis Smit.
SMIT Salvage: Dutch salvage contractor founded 1842, part of Boskalis since 2010.
Smit Tak: Historic name of the Rotterdam salvage firm founded in 1842 and now within Boskalis.
Solstad Offshore: Norwegian offshore vessel operator headquartered in Skudeneshavn.
SRP: Schottel Rudder Propeller, the manufacturer's standard azimuth thruster product designation.
Static Bollard Pull: Bollard pull measured under steady-state conditions during a witnessed trial.
Stern Drive: General term for stern-mounted azimuth propulsion.
Stern Towing: Towage in which the working line leads from a winch positioned aft.
Suderman & Young Towing: Historical US harbor towage company on the Gulf Coast.
Sumitomo Rubber: Japanese manufacturer of marine pneumatic fenders sold under the Yokohama brand.
Svitzer: Towage operator and subsidiary of A.P. Moller-Maersk, headquartered in Copenhagen.

T

Tail: Fiber rope tail spliced onto a wire to allow handling on capstans.
Targe Towing: UK towage operator based in Montrose providing harbor towage in Scottish ports.
Terminal Tug: Dedicated tug assigned to a single oil, LNG, or container terminal.
Tilbury Towing: UK harbor towage operator at the Port of Tilbury on the Thames.
Tonnes Bollard Pull: Standard unit for stating a tug's pulling capability, abbreviated tbp.
Tow Hook: Quick-release hook used on conventional tugs in place of a winch for the working line.
Towage Plan: Documented arrangement of tugs, lines, and procedures for a specific ship movement.
Towing Bridle: Y-shaped assembly connecting a single towline to two attachment points on the towed object.
Towing Pin: Retractable pin used to guide the towline on stern-drive tugs.
Tractor Tug: High-maneuver tug using Voith Schneider or ASD propulsion.
Trelleborg Marine and Infrastructure: Swedish marine systems supplier producing fenders and mooring equipment.
Tsavliris Salvage: Greek salvage company based in Athens with worldwide LOF experience.
Tug Master: Skilled professional master of a tug.
TundRA Tug: Robert Allan Ltd tug design for ice-class operations in Arctic and subarctic environments.

U

Unterweser Reederei: URAG, Bremen-based German towage and offshore operator.
URAG: Unterweser Reederei AG, German towage company headquartered in Bremen.
URS: Union de Remolcadores Sud, Spanish towage cooperative operating in Andalusian ports.

V

Vane Brothers: US bunker and tug operator headquartered in Baltimore with ATB and harbor operations on the East Coast and Gulf.
Voith Schneider Propeller: cycloidal propeller used on Voith Water Tractors.
Voith Water Tractor: Tug arrangement with two VSPs forward and a skeg aft, providing 360-degree thrust direction.
VSP: Common abbreviation for Voith Schneider Propeller.