Use of Anchors Procedure SP0242, =MANEWROWANIE= [ Pobierz całość w formacie PDF ]
//-->Use of Anchors ProcedureStandard Operating PracticesPurposeScopeResponsibilitiesMasterChief OfficerOfficer in Charge of AnchoringProceduresAnchoring ConsiderationsAnchoring Equipment DesignScope of the CableNature of the BottomLimitations of the EquipmentAnchoring LocationLetting Go the AnchorSecuring the Anchor after anchoringDeteriorating Weather ConditionsDragging AnchorIf Loss of Anchor OccursAnchoring in an EmergencyWhen Heaving the AnchorSecuring the Anchor for Sea PassageDoc No:Version:SP02428PurposeTo outline the procedure when using the vessel’s anchors.Refer toAnchoring-Operational Precautions and Procedures (PT0072).ScopeThis applies to all vessels managed by Teekay Shipping Limited.ResponsibilitiesMaster••Ensuring that anchoring of the ship is carried out with due regard to the safety of personnel, thevessel and the environment.Pre planning anchoring operations. Determining a suitable anchorage based on charts, sailingdirections, prevailing and expected weather, navigational warnings, depth of water, nature ofholding ground, expected currents, and proximity of other ships and hazards.Holding a ‘pre anchoring’ meeting on the bridge explaining to all personnel involved in the use ofanchors the methods to be employed and the safety parameters, and limitations of theequipment in use.Delegating the Chief Officer or designating a deck officer to take charge of the operationsforward. If anchoring conditions are difficult, due to, for example, deep water, strong currents,rough weather or restricted waters, the Chief Officer must be the officer in charge of partyforward.Bunker barge or supply boats shall not be allowed alongside until after completion of anchoringoperations.•••UNCONTROLLED DOCUMENTPage 1 of 7Use of Anchors ProcedureDoc No:Version:SP02428••The pilot, engines and the anchor party shall not be dismissed until the vessel is confirmed‘brought up’ to her anchor and is maintaining safe distance from the nearest danger.Where the Master is concerned with the safety of the vessel with regards to the proximity of theother vessels, the depth or the nature of the bottom, then engines should be kept in readinesson standby or short notice (10 minutes), as appropriate.Chief Officer••••Ensuring that the anchor and associated equipment are operating efficiently, the brake isadjusted correctly and the brake band thickness adequate.The anchor and cable checked at regular intervals, as far as possible prior to and during eachuse, for any defects including defective shackles and loose lugs.Lubricating program for the windlass and anchor gear is executed properly and the equipmentmaintained in optimum condition.Ensuring that the officers and crew forming the anchor party forward are trained properly inevery aspect of the operation.Officer in charge of anchoring•••Executing the Master’s orders during anchoring operations.Being aware of the varying capacities of the windlass, including hydraulic motors and anchorbrakes and using them judiciously.Advising the Master of the relative direction in which the anchor cable is leading, the weight orstrain on the cable, and any other information, which the officer or the Master may considerpertinent.Ensuring the safety of the personnel involved in anchoring, through the use of appropriatepersonal protection equipment. Personnel operating the windlass should wear a face visor /shield in addition to safety goggles. Refer toSafe Workplace Procedure & PPE (SP0144).Ensuring that there are always two seamen operating the windlass brake (the rated force cannotbe applied by one man alone).Ensuring that there are two seamen to carry out the final tightening of the windlass brake oncethe anchor has been brought up (the rated force cannot be applied by one man alone)•••Procedures••Refer to the publication:List of Shipboard Publications (SP0607)andAnchoring Considerations(RF0153).Plan anchoring well in advance having due regard for:Available room at the anchorage.Other vessels at anchor.Areas to avoid.UNCONTROLLED DOCUMENTPage 2 of 7Use of Anchors ProcedureDoc No:Version:SP02428Prevailing and forecasted weather.Local tides and currents, their direction and strength.Water depth and nature of bottom.Possibility of underwater obstructionsDegree of shelter afforded.Proximity of land or other dangers.Length of stay at the anchorage.Emergency and contingency situations.Any vessel constraints.Approach speeds and direction.Suitable communication with the anchoring party.Any caution noted on the charts in use.•Explain in detail, anchoring method, options, limitations of the equipment, and safety parametersto officers and crew involved. Suitable instructions and guidance should be provided to theanchoring party. Reference of this pre anchoring meeting should be entered in the logbook.Carry out a Job Hazard Analysis or Take Five if required.If a pilot is onboard, discuss the anchoring plan as a part of the overall passage plan. TheMaster must be in full agreement with the plan.Test the main engine in the astern direction, prior to approaching the anchorage.Test radio and other communications with the anchor party well in advance. An emergency backup, such as the vessel’s talk back system, should also be tested.Avoid anchoring in rough seas or heavy swells.Avoid anchoring in or near ice.Under normal circumstances the anchor should be walked back under gear to a position justabove the water level prior to letting go on the brake.Be aware of the varying capacities of the windlass, including hydraulic motors and anchorbrakes and control their judicious use.In deeper waters, e.g. when depths exceed 40 metres, the anchor should be walked back to aposition close to the seabed prior to letting go on the brake.Only on occasion and if thought necessary by the Master the anchor may be walked back underpower.••••••••••UNCONTROLLED DOCUMENTPage 3 of 7Use of Anchors ProcedureDoc No:Version:SP02428•After the required scope of cable has been paid out secure the brake, when possible while thecable is vertical and without any weight on it, and then secure the cable stopper (pawl /guillotine).Once the vessel is brought up, establishAnchor Watch Procedure (SP0243).•Anchoring considerationsAnchoring equipment designThe requirements22of the International Association of Classification Societies (IACS) state:The anchoring equipment … is intended for temporary mooring of a vessel within a harbour orsheltered area when the vessel is awaiting berth, tide, etc. The equipment is therefore not designedto hold a ship off fully exposed coasts in rough weather or to stop a ship which is moving or drifting.An anchor should, therefore, not be expected to hold a ship in rough weather in fully exposedanchorages. The risks are highlighted by the history of incidents and ships dragging their anchors inadverse weather.An anchor provides maximum holding power when its flukes are fully embedded in the sea-bed.This occurs when the anchor shank lies on the seabed and the anchor cable pulls horizontally at theanchor shackle. When the pull increases, the cable lying on the seabed is lifted off, creating anangle above the horizontal. As the angle increases, the holding power reduces.A rule of thumb is that a pull at 5º above the horizontal reduces the holding power by 25 per centand a pull at 15º reduces the power by 50 per cent.Figure 21: An illustration of a ship at anchorScope of the cableTo maximize an anchor’s holding power, the scope of cable should be sufficient to ensure that, infair weather, a length of cable will lie along the sea-bed and thus pull horizontally at the anchorshackle. When this occurs, the cable rises gently in a curve to the hawse-pipe. The curve, orcatenary, is necessary to ensure that the cable exerts a horizontal pull on the anchor shackle. Thisabsorbs any shocks when forces on the ship due to wind, tide and current increase the pull on thecable. The length of cable, or scope, is key in establishing a catenary.Most large ships are fitted with about 12 shackles, approximately 330 m, of cable for each anchor.The common formula for calculating the minimum number of shackles required for calm weather is:Number of shackles of cable = 1.5 x√depthof water in metresUNCONTROLLED DOCUMENTPage 4 of 7Use of Anchors ProcedureDoc No:Version:SP02428Nature of the bottomThe holding power of an anchor depends to a large extent on the nature of the seabed, or holdingground. Certain types of mud and clay provide the best holding ground while rock provides theworst. Seabed conditions must be balanced with other factors, such as the water depth and theprevailing weather conditions. In strong winds, an anchored ship will yaw and at higher wind speedsit is increasingly likely to surge rapidly from one extremity of the yaw to the other. This can place ashock load on the anchor cable, breaking the anchor’s hold in the seabed. Increased yawing instrong winds, therefore, increases the risk of the anchor dragging. An anchor will drag when thetension in the anchor cable exceeds the total holding power of the anchor and the cable.Limitations of the equipmentAnchors and associated equipment are intended to work effectively in normal or good conditions.Therefore, anchor holding power calculations or estimates are not intended to, and should not, beused to determine the maximum wind speed or weather conditions in which a ship can safelyremain at anchor.Anchoring locationAnchorage situations with, the close proximity of the coast and other ships, the likelihood of themdragging anchor if the weather deteriorates, as well as congestion in the anchorage should alwaysbe taken into account. Veering additional anchor cable to ensure sufficient cable is deployed may bean option in certain conditions. However, attempting to ride out heavy weather at the exposedanchorage is not recommended by and is not consistent with the practice of good seamanship.Letting Go the Anchor••Only in an emergency should the anchor be dropped from its stowed position in the hawse pipe.As it is extremely difficult to judge the vessel’s movement over the ground, it is recommendedthat wherever possible, vessels should avoid walking back the cable after the anchor hasreached the seabed.In case the Master decides to walk back the anchor through the entire process the vessel shouldbe stopped over the ground at the time that the anchor reaches the seabed and thereafter thereshould be very minimal way over the ground. Strain on the cable is to be closely monitored. Onlyone hydraulic pump should be in operation to prevent over-speeding of the hydraulic motor.When anchoring under power keep a close watch on any strain coming on the cable and advisethe Master. Consider ceasing to pay out the cable, secure the windlass brakes and if deemednecessary remove the windlass from gear till such time as the strain has been relieved.Thereafter consider paying out on the brakes.••Securing the Anchor after anchoring••Once the vessel is brought up and excess weight on chain is eased off, apply the anchorwindlass brake fully and lower the stopper bar/guillotine in place and insert securing pin.If required to lower the stopper bar/guillotine into place, engage the anchor windlass gear andadjust the anchor chain position such that stopper bar/guillotine can be lowered in place andinsert the securing pin.Apply the anchor windlass brake fully.Disengage the anchor windlass from gear.••UNCONTROLLED DOCUMENTPage 5 of 7 [ Pobierz całość w formacie PDF ]