A harbour tug is the smallest vessel in the port and carries one of the densest compliance stacks in the industry, because everything that makes it commercially useful is gear under load. Bollard pull, towline, winch brake, emergency release, shark jaws, fairleads, staples, shackles and fendering are not support equipment — they are the product, and every one of them is certificated, inspected and surveyed by somebody. As of 1 January 2026 there is a new layer on top. IMO Resolution MSC.532(107) amended SOLAS Regulation II-1/3-13 to bring anchor handling winches under direct regulation, supplemented by the IMO Guidelines for Anchor Handling Winches in MSC.1/Circ.1662, and the definition reaches further into the tug fleet than most operators assume: winches used for deploying, recovering and repositioning anchors and mooring lines in subsea operations, which may be purpose-built or integrated into a towing winch system. Certification is required at the first renewal survey after 1 January 2026. If your towing winch also handles anchors, the question is not whether you are in scope but whether anyone has checked. Start a free trial of Marine Inspection and get the gear register in order before the surveyor asks for it.
Layer 1
Classification
Bollard pull certification, girting resistance, towing gear surveys and machinery survey arrangements, verified through periodic class survey.
Layer 2
Flag and domestic inspection
Where applicable, US towing vessels have been formally inspected vessels holding Certificates of Inspection since 2018 under Subchapter M, with third-party organisation audits and surveys under 46 CFR.
Layer 3
SOLAS II-1/3-13, new for 2026
Anchor handling winches brought under direct regulation by MSC.532(107) from 1 January 2026, with IMO guidance in MSC.1/Circ.1662 covering certification, testing, examination and maintenance.
Layer 4
Port, state and terminal
Escort tug regimes and harbour safety committee requirements impose their own testing and certificate submission obligations, independently of class and flag.
The layers do not share paperwork. The same winch brake is examined by a class surveyor, a third-party auditor, a port authority and now a competent person under IMO guidelines — each expecting the record in their own form, on demand.
The Winch Regime That Arrived in January
This is the most significant regulatory change to hit towing operators in years, and it is the one most likely to be missed, because it did not arrive labelled as a tug regulation. Book a Marine Inspection demo and see winch certification, examination and test records held against the individual machine.
Who is actually in scope
The requirements apply to anchor handling winches, defined as winches used for the purpose of deploying, recovering and repositioning anchors and mooring lines in subsea operations. These are typically installed on dedicated anchor handling vessels and offshore support ships — and on certain tugboats. Critically, such winches may be purpose-built for anchor handling or integrated into a towing winch system, which is exactly the configuration many harbour and coastal tugs carry without anyone classifying it as anchor handling equipment.
ActionEstablish in writing, per vessel, whether your towing winch falls within the definition. This is a scope determination, not an assumption, and it should be settled with your society rather than internally.
Certification
Required before use, covering plan appraisal, material verification, fabrication survey and testing. For existing equipment, certification is required at the first renewal survey after 1 January 2026, and existing valid certificates issued under other international instruments remain acceptable.
Commissioning tests
For new installations from 1 January 2026: function tests at light load, an overload test, an emergency release test, brake holding capacity, and a bollard pull test where the winch is designed for towing. Retesting is required after major repairs or modifications.
Five-yearly witnessed test
The five-yearly test should be witnessed by the Administration or a recognised organisation acting on its behalf. Testing of emergency release and residual holding force in the wire is performed with the wire attached to an onshore strong point, and functional testing beyond the static bollard pull test is still required.
Thorough examination
Conducted at annual surveys, after repairs, and in connection with load testing. Equipment found unsafe must be taken out of service and physically marked not to be used, which is an operational instruction as much as a records one.
Marking
A permanently affixed marking is required carrying manufacturer, model, serial number, installation or manufacture date, power supply, wire details, brake holding capacity, maximum line pull, bollard pull, drum size, speed and the surveyor's stamp.
Manuals and competence
Maintenance and operational manuals must be available, or reconstructed in accordance with IMO guidelines where they are missing. Personnel must be properly qualified and familiarised with the equipment, and the winch must be included in the onboard maintenance programme.
No register booklet exists
Unlike lifting appliances, there is no prescribed register booklet for anchor handling winches. IMO guidance nonetheless requires thorough examination and testing records to be legible, complete and authenticated by a competent person. In other words, the obligation to produce a coherent record is unchanged, and the standard form that would normally carry it does not exist. That gap has to be filled by your own system.
Bollard Pull Is Not a Build Document
Most operators treat the bollard pull certificate as something the yard produced once. It is better understood as a measured value with defined re-test triggers, and those triggers are maintenance events rather than calendar dates. Sign up for Marine Inspection and link bollard pull validity to the work that invalidates it.
The regulatory definition
Under 46 CFR, bollard pull means the maximum static pulling force a towing vessel can exert on another vessel or on an object when its propulsion engines are applying thrust at maximum horsepower. It is a performance measurement of the whole propulsion train, which is precisely why work anywhere in that train puts the figure in question.
Work that can require re-measurement
Main engine modification or repair
Hull modification or repair
Shaft-drive line work
Steering system modification or repair
Escort tug regimes in some jurisdictions require braking force to be re-measured after any modification or repair to main engines, hull, shaft-drive line or steering that could affect bollard pull, with the resulting certificate and vessel specifications provided in writing to the relevant Coast Guard authority and harbour safety committee before escort services resume. Testing is conducted under classification society standards at the owner's expense, though a building certificate of bollard pull for the class may be accepted as an alternative.
The practical consequence
A main engine overhaul is not only a machinery job. On an escort-committed tug it may be the event that suspends the vessel's ability to work until a certificate is re-issued and submitted. That linkage has to be visible in the maintenance system at the point the job is planned, not discovered by an operations manager on the morning the tug is due on station.
Since 1 Jan 2026
Certification Falls Due at Your First Renewal Survey
Winch certification and marking data, commissioning and five-yearly test results, thorough examination records authenticated by a competent person, manuals held against the machine, and bollard pull validity linked to the propulsion work that triggers re-measurement — held per unit rather than per vessel, and exportable for class, flag, a third-party auditor or a port authority.
What the Gear Register Has to Carry
Towing gear is the clearest case in shipping of equipment that must be tracked individually rather than as a category. Each item carries its own certificate, its own safe working load, its own discard criteria and its own history. Schedule a walkthrough and load your own gear inventory during the evaluation.
Table 1: Gear Register Requirements for Towing Operations
| Item | What Must Be Held | What Triggers Action | Where Records Are Usually Lost |
|---|---|---|---|
| Towing winch | Certification, marking data, brake holding capacity, maximum line pull, commissioning and five-yearly test results | Annual survey, repairs, load testing, and any major modification | Test results held by the attending service company rather than by the ship |
| Anchor handling winch | Everything above, plus scope determination, emergency release test and residual holding force results | First renewal survey after 1 January 2026 for certification | Nobody established whether the towing winch falls within the definition |
| Towline and pendants | Certificate, safe working load, in-service date, inspection history and discard criteria | Wear, deformation, broken wires against discard criteria, and elapsed service | Discard criteria known to the mate but not recorded as a threshold |
| Terminal gear | Individual records for winches, thimbles, chafing gear, shackles and pendants connecting the vessel to its tow | Inspection intervals, load events and visual condition | Grouped as one line item because the pieces are small and numerous |
| Emergency release | Function test records with result, method and the person who performed it | Scheduled testing and any repair to the release mechanism | Tested during drills but not recorded as an equipment test |
| Shark jaws and stoppers | Certification, load rating, examination history and hydraulic system condition | Annual examination and any hydraulic work | Treated as deck fittings rather than as certificated load-bearing gear |
| Fairleads and staples | Safe working load, weld and structural examination, wear measurement | Structural survey and observed wear at contact surfaces | Wear is visible for years before anyone records a measurement |
| Fendering | Position-mapped condition per fender with wear trending | Contact damage, progressive wear and replacement scheduling | Assessed by eye each morning with nothing written down |
| Bollard pull certificate | Current certificate, test date, testing society and vessel specification as submitted | Modification or repair to engines, hull, shaft-drive line or steering | Filed with the build documents and never linked to maintenance |
The Connection Between Tug and Tow
Regulation uses a precise term for the equipment at each end of the hawser, and it is worth adopting internally because it defines a boundary that maintenance systems routinely blur. Start a free trial and model terminal gear as individual assets rather than as a deck category.
Terminal gear, defined
Under 46 CFR, terminal gear means the additional equipment or appurtenances at either end of the hawser or tow cable that connects the towing vessel and its tow together, and may include items such as winches, thimbles, chafing gear, shackles and pendants. Every one of those is a load path component, and a tow is only as strong as the weakest item in it.
Why individual records matter
A shackle is cheap, small and easy to lose track of, and it can also be the item that parts a tow. When terminal gear is held as one line in a hierarchy, a certificate that has expired or a component that has exceeded its discard criteria has no way of surfacing. When each piece is an asset with its own safe working load, test certificate, non-destructive testing date and discard threshold, the register itself does the checking.
What a good register produces
One export covering every wire, winch, hook, fairlead, staple and shackle with its safe working load, test certificate, non-destructive testing date and any discard criteria alert — ready for a Port State Control officer, a third-party organisation auditor or a class surveyor without three days of assembly beforehand.
Every wire, winch, hook, fairlead, staple and shackle as its own asset, with SWL, certificate, NDT date and discard alert in one export.
Harbour Work and Ocean Work Are Different Businesses
The same regulatory stack applies, but the operating profile changes what maintenance planning has to solve. Fleets running both frequently apply one scheduling model to both and get poor results on the second. Book a walkthrough and see job planning built around each profile rather than a single calendar.
Harbour and Ship Assist
Duty cycleShort, intense, repeated. Many jobs a day at full power for minutes at a time, which loads gear and machinery in a pattern nothing else in shipping produces.
Availability pressureA tug that cannot sail when the pilot calls is a commercial failure regardless of why. Maintenance competes directly with revenue in a way that a deep-sea vessel's schedule does not.
Maintenance windowGenuinely short and frequently interrupted. Work has to be broken into pieces that survive being stopped mid-task by a call.
Wear driverFendering, staples and fairleads take contact loading every single job. Wear is continuous and mostly unrecorded.
Ocean and Coastal Towing
Duty cycleSustained load over days or weeks. The towline is under tension continuously rather than intermittently, and fatigue accumulates rather than spiking.
Availability pressureLower day to day, higher in consequence. A gear failure mid-ocean is a salvage situation rather than a delayed berthing.
Maintenance windowThe passage itself, if the machinery configuration allows work on a redundant unit. Pre-departure preparation carries disproportionate weight.
Wear driverTowline fatigue at fairleads and terminal gear under sustained tension, plus consumable and spares planning across a long voyage with no resupply.
Evaluating a Platform for a Towing Fleet
Run these with a port engineer and a master present. Generic maintenance features will not separate the shortlist; gear-level record keeping will. Start a free trial and test against your own gear inventory rather than a demo dataset.
Table 2: Buyer Questions Specific to Tug and Towing Operators
| Area | The Question | A Real Answer | What Should Worry You |
|---|---|---|---|
| Gear granularity | Can each shackle, pendant and thimble be held as an individual asset? | Your own gear inventory imported during evaluation with SWL and certificate fields | Deck equipment modelled as a single category |
| Discard criteria | Can we set a discard threshold that alerts before the item is used again? | Thresholds as data with escalation, not as a note in a procedure | Discard criteria held in the operations manual only |
| Winch scope | Does the system distinguish a towing winch from an anchor handling winch? | Scope status recorded per unit with certification and test regime attached | Winches modelled generically with no regulatory attribute |
| Test authentication | Can examination records be authenticated by a named competent person? | Attribution, date and result held against the test, and exportable | Test records as scanned attachments with no structured data |
| Bollard pull linkage | Does propulsion work flag the bollard pull certificate for review? | A dependency between machinery jobs and certificate validity | Certificates and maintenance in separate modules with no relationship |
| Interrupted work | Can a job be paused and resumed when the tug is called out mid-task? | Partial completion supported without losing captured data | Jobs that are open or closed with nothing in between |
| Multi-regime export | Can one record produce evidence for class, flag, a TPO auditor and a port authority? | One underlying dataset with multiple export formats | The same finding entered separately for each regime |
| Offline on deck | Can gear inspections be recorded on deck with no connectivity? | Airplane mode demonstration with photographs and a clean sync | Read-only offline, or an assumption of harbour coverage |
| Reference | Which towing operators of our size and trade use this today? | A named, contactable reference running comparable operations | Deep-sea references offered as equivalent experience |
2026 TOWING COMPLIANCE REALITY
The anchor handling winch requirements are new and still settling. They are mandatory under SOLAS Regulation II-1/3-13 as amended by MSC.532(107), entered force on 1 January 2026, and are supplemented by IMO guidelines in MSC.1/Circ.1662. Some details have been the subject of continuing discussion between societies and administrations, so confirm your own society's current position rather than relying on any published summary including this one. Certification timing differs by installation date. New installations face commissioning tests from 1 January 2026, while existing equipment requires certification at the first renewal survey after that date, and existing valid certificates issued under other international instruments remain acceptable. Local regimes stack on top. Escort tug requirements, harbour safety committee submissions and state-level testing rules operate independently of class and flag, and testing is generally at the owner's expense under a recognised society's standards. The statutory floor still applies. ISM Code Element 10 requires a documented maintenance system where the Code applies, and Subchapter M imposes its own inspection and audit regime on US towing vessels.
Frequently Asked Questions
Do the new anchor handling winch requirements apply to our tugs?
Possibly, and it needs establishing rather than assuming. The requirements apply to anchor handling winches, defined as winches used for deploying, recovering and repositioning anchors and mooring lines in subsea operations. They are typically found on dedicated anchor handling vessels and offshore support ships, and also on certain tugboats. The important detail for towing operators is that such winches may be purpose-built for anchor handling or integrated into a towing winch system — so a combined winch may bring the vessel into scope. Settle the determination in writing with your classification society per vessel, because the certification deadline runs from your first renewal survey after 1 January 2026.
What tests does the new winch regime require?
Certification before use covers plan appraisal, material verification, fabrication survey and testing. For new installations from 1 January 2026, commissioning tests comprise function tests at light load, an overload test, an emergency release test, brake holding capacity and a bollard pull test where the winch is designed for towing, with retesting required after major repairs or modifications. A five-yearly test should be witnessed by the Administration or a recognised organisation, including testing of emergency release and residual holding force in the wire performed with the wire attached to an onshore strong point. Thorough examination is conducted at annual surveys, after repairs and in connection with load testing.
Is there a standard register book for winches like there is for lifting appliances?
No, and this is a practical difficulty rather than a relief. No prescribed register booklet exists for anchor handling winches, yet IMO guidance still requires thorough examination and testing records to be legible, complete and authenticated by a competent person. The obligation to produce a coherent, auditable record therefore falls entirely on the operator's own system, without a standard form to structure it. Equipment found unsafe must additionally be taken out of service and physically marked not to be used, so the record has an operational consequence attached rather than being purely documentary.
When does a bollard pull certificate need renewing?
Bollard pull is a measured performance value rather than a fixed specification, defined under 46 CFR as the maximum static pulling force a towing vessel can exert when its propulsion engines apply thrust at maximum horsepower. Because it measures the whole propulsion train, work anywhere in that train can invalidate it. Escort tug regimes in some jurisdictions require braking force to be re-measured after any modification or repair to the main engines, hull, shaft-drive line or steering that could affect the figure, with the certificate and vessel specifications then submitted in writing to the relevant Coast Guard authority and harbour safety committee before escort services resume. Link the certificate to the machinery jobs that trigger it.
What counts as terminal gear and why does it need individual records?
Terminal gear means the additional equipment or appurtenances at either end of the hawser or tow cable that connects the towing vessel and its tow, and may include winches, thimbles, chafing gear, shackles and pendants. Each is a load path component in a system that fails at its weakest point. Held as one category in a maintenance hierarchy, an expired certificate or an item past its discard criteria cannot surface. Held as individual assets with safe working load, test certificate, non-destructive testing date and a discard threshold, the register performs the checking itself, and one export serves a Port State Control officer, a third-party auditor and a class surveyor alike.
How should maintenance be planned around harbour tug availability?
By designing for interruption rather than for uninterrupted windows. Harbour assist work is short, intense and repeated many times a day, and a tug that cannot sail when the pilot calls is a commercial failure whatever the reason. That means jobs need to be broken into stages that can be paused and resumed without losing captured data, and the system has to support partial completion rather than treating work as open or closed. Ocean towing inverts the problem: the window is the passage itself where machinery redundancy allows it, availability pressure is lower day to day, and pre-departure preparation carries disproportionate weight because there is no resupply.
Harbour and ocean towing
The Gear Is the Business. Register It Like It.
Every wire, winch, hook, fairlead, staple, shackle and pendant as its own asset with safe working load, certificate, non-destructive testing date and discard threshold. Winch certification and test records authenticated by a competent person. Bollard pull validity linked to the propulsion work that triggers re-measurement. Fender condition mapped by position with wear trending. Captured on deck with no connectivity, resumable when the call comes mid-job, and exportable for class, flag, auditor or port authority in one pass.
