Anchors and Anchoring


FOM-3.39	Fleet Operations Manual Navigation Anchors and Anchoring	Doc No.: FOM-3.39 Revision: 01 Date: 15 Oct 2024 Issued by: DPA Approved by: MD

1. APPLICATION

This document applies to Masters, Deck Officers, Chief Engineers and Bosun on-board all fully managed vessels.

2. PURPOSE

The purpose of this document is to specify requirements for the safe and efficient anchoring of vessels.

3. RESPONSIBILITIES

3.1 Master

Prepare anchoring plan with OOW
Select suitable anchorage
Ensure anchor handling supervised by responsible officer
Ensure compliance with NAV-19 checklist
Ensure depth is below maximum anchoring depth

3.2 Deck officers

Supervise anchor handling
Assist Master in preparing anchoring plan
Report lead of the chain to Master
Monitor anchor position

3.3 Chief engineer

Ensure good condition of steam operated windlass

3.4 Bosun

Clear anchor lashings when instructed
Anchor handling under supervision of responsible officer

4. FAMILIARISATION

Deck officers must:

Familiarize themselves with the anchoring equipment
Check braking system with special attention to:

Brake lining thickness
Clearance between the take up bolt & brake lining
Condition of chain stopper & pin
Condition of D-shackle
Greasing of various parts

5. MAXIMUM ANCHORING DEPTH

Display maximum anchoring depth on the bridge.

Note:

Refer to OCIMF publication “anchoring system and procedures”.

Table 1. Calculation table

Weight of anchor (a)	KGS = Tonnes
Weight of chain (b)	KGS = Tonnes
Weight of each shackle	B/No of shackles = KGS = Tonnes
Continuous pulling power “Z“ KGS	Constant X (Chain diameter)² Where 4.75 is for grade 3 chain. = KGS = Tonnes

Vessel windlass rated load is “x” t x 10 m/min
All calculations are based on vessel’s continuous pulling power of tons.

Cont. pulling power “Z”	= Tonnes
Safety allowance 10%	= (-) Tonnes
	= Tonnes
Weight of anchor	= (-) Tonnes
Weight of 1 shackle of chain	= Tonnes
Maximum length of chain vessel’s windlass can heave up from forecastle level	= Shackles Mtrs
Freeboard forward in ballast passage	= (-) Mtrs
Max depth for anchoring	= Mtrs

6. GENERAL GUIDELINES

6.1 Small and medium size vessels

6.1.1 Vessels <65000 DWT in shallow waters (<40 meters)

Lower anchor to water level on gear
Let go once in position
Control lowering using brakes
Use engines as required

6.1.2 Vessel <65000 DWT in deep water (>40 meters)

Walk back procedure is recommended for vessels <65000 DWT in deep waters (>40 meters).

6.2 Large vessels

CAUTION:

Do not let go anchor for large vessels.

Use walk back method
Record position of vessel – position of anchor will be determined and is used to establish centre of swinging circle.

6.3 Limitations of anchoring equipment:

Used for temporary mooring within harbour or sheltered area awaiting berth.
Not suitable for:

Holding vessel in exposed coasts with rough weather
Stop a moving of drifting ship

Maximum environmental limitation for sheltered waters:

Current velocity: max. 2.0 m/s or 4 knots
Wind velocity: max. 15 m/s or 30 knots (Beaufort wind scale 7)
No waves or swell

Maximum environmental limitation for non-sheltered waters:

Current velocity: max. 1.5m/s or 3 knots
Wind velocity: max. 11m/s or 22 Knots (Beaufort wind scale 6)
Significant wave height: max. 2m

Note:

Use both anchors on rotation basis & record in the log book.

6.4 Factors for suitable anchorage

Consider following to select suitable anchorage:

Degree of shelter
Depth of water (UKC not less than 2 meters, Ref. to FOM 3.33 Under Keel Clearance)
Nature of holding ground
Length of stay
Tide
Distance of hazards
Loaded or ballast condition
Weather conditions
Current
See FOM 3.37 Anchoring in Areas Having Strong Current

CAUTION:

1. Inform Marine Superintendent in advance if the vessel is expected to anchor in an area having current: More than 4 knots in sheltered waters. More than 2 knots in open waters. Immediately when vessel drags anchor and before any attempt to re-anchor. 2. Avoid anchoring vessel near River bends exposed to cross currents. Call Port Tugs when vessel has heavy yawing and heave up anchor and re-anchor at another location with reduced currents.

6.5 Windlass and Anchoring

These will be most effective if tightened up at the moment that the maximum weight comes on to the anchor cable.

Cable stopper form and integral part of the anchor cable restraining equipment and are designed to take the anchoring loads.
Anchor cable lengths to be clearly marked with white paints or stainless steel bands, even when cable counters are fitted.
Provision is sometime made to compensate for brake lining wear. Consult maker’s instructions and make sure you are familiar with this facility.
If in doubt about the brake holding efficiency report it.
Do not stand in line with the cable when it is under load or being “run out” or hove in, PPE to be worn as per the PPE matrix.

6.6 Windlass operation

Training of the deck crew involved with mooring / windlass operations to reinforce following practices:

Windlass should be operated carefully to ensure that excessive external force are not acting (especially in heavy weather), otherwise the motor and other equipments may get damaged.
Before heaving up anchor, it should be ensured that the anchor chain hangs down vertically. This should be ensured by movement of the vessel using main engine.
In case that the windlass slows down or stops during heaving operation, it shows that excessive load applies on the windlass. In such cases main engine should be used (with chain stopper applied) to assist with anchor movement.
Before reversing the motor direction, during operations, operator should wait for sometime, keeping the control lever at the neutral position.
Before the motor is operated with brake disengaged, brake lever should be opened adequately to ensure that the brake is clear of the drum.
It should be carefully observed during operations that there are no slippages when anchor is held hydraulically in stationary position, and that the motor and chain move smoothly when operated. Else, remedial measures should be taken for repairs on the hydraulic system.
Instructions to this effect should also be suitably posted for reference of all operators.

7. ANCHORING

7.1 Prior arrival & during approach

In planning the anchorage approach, the Master should consult with the charts and pilots books as to the suitability of the holding ground of the anchorage, and also with respect to traffic density and ship movements, available swing room, holding ground, protection from the weather, wind, tide and the length of time the vessel is expected to be at anchor.

Masters should not just accept the fact that ‘the authorities’ have directed the vessel to anchor in a particular designated anchorage. There are many designated anchorages that are unsuitable in certain conditions, particularly with the onset of heavy weather, closeness to the shoreline, traffic density, exposure to the weather, water depth, and/or poor holding ground. If instructed to a designated anchorage, the Master must ascertain for himself that the anchorage is safe in the prevailing conditions and if not satisfied the Masters should be prepared to inform the VTS or port authority that the designated anchorage is not suitable in the prevailing conditions.

Remove both anchor lashings

Note:

Secure anchor bar & brakes prior removing lashings.

Clear spurling & hawse pipes
Stem the tide during approach (recommended)
Reduce speed in time
Ensure bitter end arrangements in place

7.2 Prior anchoring

Test communication between bridge & anchor party.
Check over side clear of any obstructions/small crafts
Stop the vessel over ground before letting go
An anchor-marking buoy is to be ready on the forecastle for use in marking the anchor position in the event the anchor and cable are slipped.

7.3 During anchoring

Use engines to prevent cable tension
Pay out necessary cable length to prevent anchor dragging
Inspect chain, shackles & pins

Note:

Use at least 6 x depth of water cable length.

7.4 After anchoring

Secure brake & anchor bar
Place flag on the windlass to warm OOW in case dragging anchor
Hoist “anchor ball” forward when the anchor reaches the bottom
Display correct anchor lights and shapes as well as deck lights at all times when anchored and update the vessel status on AIS.
Check anchor bearing & plot swinging circle
Monitor anchor position & log down at least hourly
Enable anchor watch alarm on GPS/ECDIS
Inform port authorities
Keep engines on short notice
Regularly monitor tension of the anchor chain
Monitor weather forecast
Keep second anchor ready for use in case of dragging

CAUTION:

‘ Poster 041- Safe Anchoring’ and ‘FOM 3.38 Methods of Anchoring’ should be referred for additional guidance. Refer to OCIMF publication “anchoring system and procedures” section 5.4 for emergency anchoring.

8. SECURING OF ANCHORS AND CABLES

8.1 Prior COSP

Physical verification of the condition of anchoring equipment
Anchors home to avoid banging against the hull
Stopper bar is down with pin in place
The weight of anchor is on the stopper bar
Take additional lashings
Record in log book

CAUTION:

Take additional lashings in case of rough weather.

8.2 Loss of anchor

Notify Company emergency number
Contact local agents
Record position of anchor & include in initial message
Consider recovery if time & schedule permit
Review & prepare recovery equipment
Order additional equipment as required

9. ADVERSE WEATHER

When Underway
- The Master is to ensure that additional securing arrangements are made in anticipation of adverse weather.
- The securing arrangements should be checked every three days during prolonged periods of heavy weather (this may mean altering course to allow safe access to the Forecastle).
At Anchor
- If the Master or Officers are in any doubt as to the security / safety of the vessel, the engines must be immediately brought to readiness.
- The Master should assess the situation and if thought necessary, weigh anchor. Master is guided by section 6.3 (limitation of anchoring equipment) above.
- This decision should not be left too late so that additional weight is put to bear on the cable and windlass when heaving.
- The stress on the cable can be eased by using the engine, and thrusters if fitted or using the rudder to attempt to reduce yawing, especially in a current.
- Frequent weather forecasts must be obtained and evaluated when the vessel is anchored.
- Assessment should be made with respect to the direction of the wind, current, effects of sea and swell, holding ground like etc.
- While at anchor, considerable dynamic stress on the anchor system may be induced due to yawing of the ship under influence of wind and tide. This yawing can be moderated by lowering a second anchor on to the sea bed and when 2nd anchor is being made ready the anchor and the shank to be lowered inside the water to dampen the effect of anchor banging against the ship side due to rolling
Freezing Weather Precautions
- Chief Engineer is responsible for ensuring that steam operated windlasses are protected against consequences of freezing, when in operation. This can be accomplished by:
- Deck OOW is responsible for ensuring that program is carried out in accordance with Chief Engineer's instructions

10. DRAGGING ANCHOR / EMERGENCY DEPARTURE FROM ANCHORAGE

Raise General Alarm, inform master
Warn other ships in the vicinity
if necessary, seek the help of harbour or port pilots and tugs
Inform engine room, and prepare the main engine for manoeuvring
Pay out additional length of cable
Try to hold the vessel in position using Main Engine
Call up office immediately or send an email, depending on the urgency, detailing the circumstances of the anchor dragging and action being taken by Master.
If risk of collision or contact with another vessel exists then, vessel should consider which of the two is the better option to be taken within the short time available:

picking-up anchor and moving away or
paying out / slipping the cable to increase the distance / time from contact.

If time and circumstances permit, pick-up anchor and move to a safer location.
If time or circumstances do not allow for picking up the anchor then:

Try running out the rest of the chain to increase distance.
If this is likely not to or will not avoid contact with other vessel then cable may be slipped from the bitter end and the vessel maneuverer out of the danger.

If time or circumstances do not allow for slipping of the anchor then use engines boldly to dredge/drag the anchor, provided there is no underwater obstructions.

Note:

In an emergency, if collision is imminent, it is preferable to lose the anchor than to have contact with another vessel. In many cases it has been observed that even when collision is imminent (where another vessel is dragging on to own vessel at anchor, etc.) the Bridge team tend to be intent on picking up the anchor. This will only result in precious time being lost and will do very little to avert an impact. In such cases losing the anchor and chain is far less expensive and damaging than a collision. So if the situation warrants DO NOT HESITATE to slip the anchor.

CAUTION:

The crew should be in a safe area well clear of the windlass and anchor chain while dredging the anchor.

11. EMERGENCY ANCHORING

Master to be fully aware of the emergency anchoring procedure as laid down in Section 5.4 of the OCIMF Publication “Anchoring system and Procedures” and comply with the procedure when anchoring in emergency.
Master to confirm that depth is below the Maximum anchoring depth as mentioned under Section 5 of this section.

12. REFERENCED FORMS AND CHECKLISTS

NAV-20 - Anchor watch log
Poster 041 Safe Anchoring

13. APPENDICES

FOM 3.37 Anchoring in areas having strong current
NAV-19 Anchoring and anchor watch
FOM 3.39 Anchors and anchoring