⚓ OVID -- AHTS/TUG Operations (Escort Tug, Towing, Anchor Handling)

Replacement policy should be based on Manufacturer’s recommendation and periodic onboard line inspections. Independent third party testing results should be used to verify the length of service time.

Contact surface should be clean and smooth with non-abrasive fittings to avoid damage. Surface maintenance should be part of routine inspection program.

All chains and hardware used to secure the fenders should be in good condition and the fendering placed in such a way as to avoiding steel to steel contact when working alongside a vessel.

Operator refers to the vessel master or deck officer who is on watch and handling the vessel.

If visibility is limited are there means such as radios or deck talk-back boxes used to communicate with crew. Inspectors shall ask crew to operate all such devices and note what the visibility restrictions are and how they are addressed by vessel crew. Inspectors should determine if the vessel has a folding mast and if precautions are being taken to avoid the mast making contact while working alongside a vessel.

A recessed bit is defined as a bitt inset into the ship’s hull above the water line used to connect the tow line. Inspectors should look for a formal procedure that covers working with recessed hull bitts. These bitts usually have reduced SWL that the vessel operator should be aware of. Additionally, they require extra caution for the tug crew when connecting the vessel’s line to.

Inspectors shall list the SWL of the Staple. Staple may also be referred to as the fwd towing staple or towing fair lead.

Indirect towing is a method used by tug to exert dynamic forces on the tow line substantially beyond its static bollard pull; e.g. using a tug's weight, bulk and underwater surface area or by turning obliquely to a tow line to produce additional forces to stop or turn a ship under way.

Inspector to verify that all crew are aware of any limitations when utilising forward and aft towing arrangements

Inspectors shall sight and record the date of last calibration. Calibration may be a full calibration done during a bollard pull test or, in the case of older models, may be done by setting the tension monitor to zero when the there is no tension on the winch.

Interview Master on the topic and identify what document is referred to.

List the type, bollard pull and any outstanding deficiencies. Inspectors shall visibly inspect each winch. Mounting brackets should be in good condition with no obvious cracks or defects. Hydraulic and air hoses shall have all fittings tights and no leaks present. Winch controls should be in good working order with minimal wastage. If a hook is used in lieu of a winch describe details. Winches are to be lubricated per vessel’s preventative maintenance schedule.

Inspectors shall visibly inspect each emergency release system. Provide details of the last test.

If yes, please state class or certifying notations. Make a clear statement if the certificate is more than 5 years old.

Fenders should be fitted in areas of the probable contact with another vessel’s hull during towing assistance (e.g. pushing), ship-to-ship personnel or equipment transfer. All chains and hardware used to secure the fenders should be in good condition and the fendering placed in such a way as to avoiding steel to steel contact.

Inspectors shall visibly inspect each winch. Mounting brackets should be in good condition with no obvious cracks or defects. Hydraulic and air hoses shall have all fittings tights and no leaks present. Winch controls should be in good working order with minimal wastage. Winches are to be lubricated per vessel's preventative maintenance schedule.

Inspectors to check condition of all towing condition including shackles, gobbing arrangements and observe general condition.

Original wire certificates should be available. If long nose spelter sockets are on work/tow wire record as observation

Tow line assemblies (pennant and stretchers) must be replaced every 12 months. Any extension in replacement past 12 months shall be made based on formal analysis by a 3rd party SME and confirmation that the components are stored and maintained between use in accordance with the manufacturer’s guidance. On vessels where inspections of the tow line assembly identify significant damage, replacement may be less than 12 months. Connecting shackles must be replaced every 36 months provided they are fully inspected, tested and certified using NDT techniques annually.

Tow log should as a minimum record the following date installed, certificate number and issuing authority, time in use, shock or unusual loads, inspection results, size, MBL, and length. The record of service must contain confirmation of towing drum and contact surface preparation is suitable for installation and the use of towline was in accordance with manufacturer recommendations. Reference IMO MSC/Circ.884

Bollard Pull (BP) less than 40T then MBL= 3.0 x BP; Bollard Pull (BP) = 40T to 90T then MBL = (3.8-BP/50) BP; Bollard Pull (BP) greater than 90T then MBL = 2.0 x BP (all numbers in tonnes). Reference IMO MSC/Circ.884

The contingency plan should include MOB, measures to be taken following the loss of tow, towline parting, propulsion failure and the onset of adverse weather, including heaving to and taking shelter. When vessel is engaged in towing operations do procedures require all weathertight doors, hatches, manholes, ports and windows on the weather deck required to be closed and secured to prevent downflooding in the event of deck edge immersion? A check to ensure that such arrangements are closed should be included in a pre-towing checklist. They should also be easily identifiable, for example by painting doors and hatches a different colour or with a warning on both sides saying "To remain closed while towing". Should a situation arise where tension in the towline causes the tug to heel over and the deck edge to be immersed, the delay in down flooding afforded by having watertight integrity on the weather deck may be vital in providing sufficient time for the quick release mechanism to be activated or for the tug to be manoeuvred to lessen the tension in the towline

Searchlight should provide illumination both forward and aft, allowing tug to approach the tow either bow or stern on.

If any terminations use long nose or hand-spliced, respond 'No' and provide an observation.

Inspectors shall sight and record the date of last calibration. Calibration may be a full calibration done during a bollard pull test or, in the case of older models, may be done by setting the tension monitor to zero when there is no tension on the winch.

Alarm to be set for slippage/overloading of winch

Tension gauge should be calibrated annually. Inspector to document date of last calibration.

There should be evidence that wires are regularly lubricated. Inspector should check first layers of towing wire and look for flattened areas, broken strands, heavy external corrosion or kinks. Inspector should confirm records are available to demonstrate destructive testing is carried out on a periodic basis.

Replacement policy should be based on Manufacturer's recommendation and periodic onboard line inspections. Independent third party testing results should be used to verify the length of service time.

Contact surface should be clean and smooth with non-abrasive fittings to avoid damage. Surface maintenance should be part of routine inspection program.

Sufficient towing wire protectors shall be provided to prevent the towing wire from being damaged by abrasion and chafe against tow bars, cargo protection rails, bulwarks or stern roller.

Risk assessment, procedures and checklists in place to address the issue of girting. A towline under tension will exert a heeling moment on the tug if the line is secured around amidships and is leading off toward the beam. If the force in the towline is sufficiently powerful, it may overcome the tug's righting lever and cause it to capsize. Girting can occur very rapidly, and incidents have occurred where crew members have not been able to escape in time. Moreover, it should not be assumed that the winch or winch brake will render or that the towline will break before a potential girting situation occurs as less force may be required to capsize the tug.

Comment on the frequency and nature of testing (under load or static) and crew familiarity with the nature of the release. Maintenance and testing of these systems should be included as part of the planned maintenance regime.

There should be documented procedures available and associated risk assessments for the cutting of such wires in an emergency.

Where used, stretchers shall have a minimum MBL of 3 times vessel bollard pull. Reference: OCIMF Static Towing Assembly Guidelines (STAG)

State Master's experience. For U.S. mariners (license endorsement or Towing Officer Assessment Record) or countries which require documented towing competence assessments or a towing endorsement on their license, is such license endorsement or documented assessment in place.

Examples of non-conventional propulsion systems: Azimuth Stern Drive, Voith Schneider or Rotor Tug Propulsion. Master and/or any officers with direct responsibility for ship handling should undertake a formal ship handling familiarisation course or programme having the objective to maximise the benefits of propulsion fitted and enhance the efficiency of towing operation. This can be a combination of real and/or simulated environment. Participation in any such programme should be recorded.

Check that assessments include equipment deployment and recovery operations.

Inspector to interview Master/officers on this topic and identify what limiting criteria is used for reference (including weather limitations, thruster limits, etc).

All the loading conditions reported in the trim and stability booklet, with the exception of lightship, should have been checked by class in order to investigate the ship's capability to support the effect of the towing force in the beam direction. Master of the vessel should receive information in the Trim and Stability Booklet regarding cargo and/or ballast limitations, list of protected flooding openings that need to be kept closed, wind and/or wave restrictions, etc., necessary to ensure that the stability is in compliance with the criteria applicable. If any loading condition requires water ballast for compliance with the criteria, the quantity and disposition should be stated in the Guidance to the Master.

Guidance - Indirect towing is a method used by tug to exert dynamic forces on the tow line substantially beyond its static bollard pull; e.g. using a tug's weight, bulk and underwater surface area or by turning obliquely to a tow line to produce additional forces to stop or turn a ship under way.

Operator refers to the vessel master or deck officer who is on watch and handling the vessel.

If visibility is limited are there means such as radios or deck talk-back boxes used to communicate with crew. Inspectors shall ask crew to operate all such devices and note what the visibility restrictions are and how they are addressed by vessel crew. Inspectors should determine if the vessel has a folding mast and if precautions are being taken to avoid the mast making contract while working alongside a vessel.

Available quantity should take into account the need for communication of tug personnel deployed on board an unmanned tow for inspections or during an emergency.

To include, e.g. the operation of winch stops, wire release and the shutdown of associated systems. It must be stated that towing must be discontinued, the gear and equipment relieved or emergency released if the vessel is exposed to greater load/force/tension than anticipated in the plans.

Use of thrusters and/or winches may reduce the available power for main propulsion resulting in a reduced bollard pull. Masters should be aware that bollard pull, as measured for the vessel's certificates, in some cases, does not allow for the power used by deck machinery, thrusters and other consumers diverted from the main propulsion. As a minimum, curve showing the maximum available bollard pull for anchor handling as function of total electrical power balance (accounting for the power consumption of side or azimuth thrusters and winches) must be available to crew.

A recessed bitt is defined as a bitt inset into the ship’s hull above the water line used to connect the tow line. Where applicable, inspectors should look for a formal policy that covers working with recessed hull bitts and require extra caution for the tug crew when connecting/disconnecting the tow line.

Guidance - Inspectors shall list the SWL of the Staple. Staple may also be referred to as the fwd towing staple or towing fair lead.

If yes, state class and service notation. Inspector to check if AHTS equipment is included is class survey records.

Record date of test and continuous bollard pull as per certificate. If certificate is more than 5 years old, not issued by current Class and/or not in current vessel name record as observation.

Original wire certificates should be available. If long nose spelter sockets are on work/AH wire record as observation.

All wires should be subject to annual inspection by an independent competent party. Wires should be re-socketed once every 2.5 years. Sections of work wires and tow wires should be cut and sent for shore analysis by RO approved vendor at intervals not exceeding 5 years.

The assessments must also embrace the risk to which the vessel can be exposed. During recovery and deployment of anchors, the vessel will often be affected by great forces. A high level of tensile forces (tension) in the chain or wire may cause great heeling moment and high astern or transverse speed of motion in the anchor handling vessel. A simultaneous loss of thrust force on the vessel's own propellors and or fatal rudder position may result in a rotation which leads to a considerable increase in transverse forces. Environmental conditions as wind, waves and currents will also influence the operations.

Procedures for unintended situations and in particular entire or partial loss of bollard pull, are to be established. They should describe, for each type of equipment (including but not limited to anchor handling winch, wire/chain stopper (such as Karm Fork or Shark Jaw)), emergency release methods, time delays and release speed in both normal operating condition and dead ship condition. Entire or partial loss of vessel's bollard pull will cause the vessel to be pulled astern with great forces by the tension in anchor arrangement. These procedures are to be known by the crew and vital information displayed on the bridge or any other appropriate location.

Calculations must show the max acceptable tension in wire/chain in order for the vessel's maximum heeling to be less than one of the following angles whichever occurs first: Heeling angle equivalent to a GZ value equal to 50% of GZ max; The angle of flooding, which results in water on working deck; 15 degrees. The most unfavourable conditions for transverse tension are to be considered for the calculations, usually chain acting transversely over the side to the outer pins. The displayed information is to be under the form of curves, prepared so that the master can easily determine the maximum tension that can be applied to the vessel, as a function of the draught, trim and horizontal angle between the longitudinal axis or the guide pin and the wire/chain. (Ref NMD circular Date: 03/31/2014 / Number: RSV 3 - 2014)

To include, e.g. the operation of winch stops, wire release, wire/chain stoppers and the shutdown of associated systems. It must be stated that anchor handling must be discontinued, the gear and equipment relieved or emergency released if the vessel is exposed to greater load/force/tension than anticipated in the plans.

Comment on the frequency and nature of testing (under load or static) and crew familiarity with the nature of the release. Maintenance and testing of these systems should be included as part of the planned maintenance regime.

Check, if appropriate, that deep water anchoring operations are included. Though it is recognised that this is an arbitrary distinction, "deep water" is generally considered to be depths in excess of 300 metres. However, any assessment of what might be considered as "deep water" operations should take into account the capabilities of the vessels supporting such activities. During deep water moves the weight on stern roller can be hundreds of tonnes, which may be applied at a distance off centre line according to the set-up of the towing pins. This may add to listing moments and stern trim, increasing the risk of a flooded deck, e.g. from a breaking wave which can maybe result in a temporary reduction in stability.

During tandem and/or joint towing operations, the towing gear must be connected with emergency release so that in case of a breakage in towing line or loss of power/bollard pull in one of the vessels, the other vessel may quickly be disconnected. A communication plan for the operation must be established which in particular ensures an effective and coordinated action in case of any unintended incident.

Vessel's operating procedures for bridge manning should be in line with industry standards such as GOMO, which requires 2 deck officers to be present during anchor handling operations.

The stability manual should address the effect of slack tanks and the sequence for emptying fuel oil and potable water tanks.

The use of anti-roll tanks can adversely affect stability.

Equipment may include anchor handling winch, AH wire, Work wire, pennant wires, stretcher ropes, Gob wire/chain, wire/chain stopper such as shark jaw/karm fork, spooling gear, stern roller. There should be evidence that wires are regularly lubricated. Inspector should check first layers of anchor handling wire and look for flattened areas, broken strands, heavy external corrosion or kinks.

Where fitted, inspector should record company policy regarding frequency of winch tension measurement calibration and function testing of render function if fitted. Record date of last calibration, calibration should be within 12 months.

Use of thrusters and/or winches may reduce the available power for main propulsion resulting in a reduced bollard pull. Masters should be aware that bollard pull, as measured for the vessel's certificates, in some cases, does not allow for the power used by deck machinery, thrusters and other consumers diverted from the main propulsion. As a minimum, curve showing the maximum available bollard pull for anchor handling as a function of total electrical power balance (accounting for the power consumption of side or azimuth thrusters and winches) must be available to crew. Note: Inspector should consider vessel power generation as, where vessel propulsion is direct drive, the bollard pull should not be affected by power consumption.

Check certification and inspection records. Inspector to check wire condition for broken wires, lack of grease, hand- spliced eyes, etc. Check that protection is provided for operators.

Deck or engineer officers should undertake a formal anchor handling familiarisation course or programme. This can be a combination of deck and bridge experience in a real or simulated environment. Participation in any such programme should be recorded. Able seamen should be trained in guidelines, procedures and safe equipment use before assignment to independent anchor handling work on deck. All training is to be documented. At least captain, chief mate and one member of each deck watch should have performed a minimum of 5 anchor handling operations. Inspector should report level of training and experience as a comment. Master must be familiar with; maximum force/tension in wire or chain, as well as corresponding lateral point of direction to meet maximum heeling. criteria; any tank restrictions (i.e. ballast tank and/or roll reduction tank usage, fuel oil burn off sequences, etc.) determined. by the stability calculations; list of protected flooding openings that need to be kept closed; wind and/or wave restrictions.

Winch operators should be competent in the winch design and operation, control systems, operating modes, emergency release systems and limitations. They should also be competent in the use of towing pins, shark jaws and associated torque-release equipment as well as pulling power and the impact on stability. Winch operator should undergo formal training preferably in collaboration with manufacturer. Inspector should report level of training and experience as a comment.

For example are remote video (CCTV) coverage of garage located winches available on the bridge. Inspector to provide comment if CCTV system has the capability to record.

Prior taking part in anchor handling operation, Master should make sure that calculations are carried out and that plans are made clearly showing the loads/forces (tension) that may occur. If necessary, this information must be recovered from the principal. Such calculations must take into consideration the weight of the anchor lines (chain) in question and the anticipated force/tension which may occur or be required in any phase of the operation. Verification must be made that the calculated forces are within capacity of the vessel.

Check communication equipment (intercoms and UHF/VHF had-held radios) including backup arrangements.

Inspector should verify satisfactory operation of equipment, including review of below deck areas in vicinity of equipment noted within question for signs of water ingress.

International Code on Intact Stability Part B – “Ships engaged in anchor handling operations” , is described in chapter 2.7.5.1 of RESOLUTION MSC.415(97) (adopted on 25 November 2016) AMENDMENTS TO PART B OF THE INTERNATIONAL CODE ON INTACT STABILITY, 2008 (2008 IS CODE). Two types of stability instrument may be used on board: either a software checking the intended or actual tension on the basis of the permissible tension curves; or; a software performing direct stability calculations to check compliance with the relevant criteria, for a given. loading condition (before application of the tension force), a given tension and a given wire position (defined by angles α and β).

Inspector should review potential and actual installation of anchor handling system deck cover plates, protection systems for ship electronic control systems in vicinity of potential water ingress areas by way of Towing pins and wire/ chain stoppers.

Inspectors should review instructions provided to masters and crew with regards to application of silicone sealant, installation of gasket or other means as appropriate.

Inspectors should review ensure appropriate instructions are in place to ensure systems are verified watertight following maintenance and/or inspection.