145292848 Mooring of Ships Forces 2

Mooring of ship - TVS 1ste kan 1

Mooring of ships - forces

Kapt. K. De Baere


Purpose of mooring configuration

To bring the ship alongside

To keep the ship alongside

To assist the ship when un-mooring


Design criteria of mooring configurations

Based on the forces acting upon the ship

Wind

Current

Waves

Swell

Other ships passing by (suction effect)

Location of the berth – Protected or sea berth

Types of ship – size, displacement, draught etc.


Protected berths

Design criteria – limiting values

Cross wind up till 15m/sec (6-7 Beaufort)

Tidal current of 3 knots in longitudinal direction

Cross current of 1 knot

Cargo- and container ship are normally moored along well protected berths => Mooring winches are designed to pull the ship alongside with 1 headline and 1 stern line against a cross wind of 5 Beaufort


Sea berths – designed for >wind

Design criteria – limiting values Cross winds up till 20m/sec or 8

Beaufort and gust of winds up till 10 Beaufort

Tidal current of 3 knots in longitudinal direction

Cross current of 1 knot Waves and swell

Waves and swell with a short period have a limited influence


Fetch

The size of a wave depends on its fetch. The fetch is the distance a wave travels (see next slide). The greater the fetch, the larger the wave.

If the wind is blowing for a longer period of time in the same direction => long fetch with a high wave height and a longer period => important dynamic effect on the ship


Fetch – Definition Growth rate of wind generated waves

The distance that wind and seas (waves) can travel toward land without being blocked. In areas without obstructions the wind and seas can build to great strength, but in areas such as sheltered coves and harbours the wind and seas will be calmer.


Mooring of VLCC’s

Often moored outside the harbours along sea berths

Forces are so great that no winch is capable of bringing the ship alongside

Tugs are always used when mooring and leaving berth

The only criteria is the holding force of the winches

The ship must be maintained in position related to the shore manifold (chiksans)


Relation maximum pulling power – Displacement ()

Figures are used to design shore facilities (bollards, bits ……….. Etc.)

25% safety margin to be added

8000 ton – 100 kN 10.000 ton – 300 kN

20.000 ton – 600 kN 50.000 ton – 600 kN

100.000 ton – 1000 kN 200.000 ton – 1500 kN

1 kN = 1 ton pulling power (not scientific)


Mooring winch with undivided drum


Mooring winches – Divided drum-polyprop octopus


Chicksan


Chicksan

One of the biggest problems with the fixed loading/discharging systems is the restricted liberty of movement of the ship

If one of the limits is breached => ESD-system activated


Assessing the forces

1. Forces due to wind and current are proportional to the square of their speeds. f.i. the force caused by a wind of 40 knots is 4 times the influence of a wind of 20 knots

2. The wind speed increases with the height above the ground. A wind of 10 knots at 2 meters increases till 60 knots at 40 meters => importance of the freeboard (height of the structure). To obtain comparable figures all winds are recalculated to a standard height of 10 meters


Maximum wind limits (400.000 dwt ship) in function of the breaking power of the winches


Wind limits

The previous pictures learns us that;

1. The wind limit is determined by the holding power (breaking power) of the winches

2. The wind limit is determined by the material of the mooring lines


Assessing the forces

3. Influence of a cross current is inverse proportional with the keel clearance. In case of a small keel clearance the current is obstructed by the ships hull and searches way out via the stem and the stern. A Suction effect is created trying the move the ship away from the berth.


Theoretical example of the influence

of the keel clearance

A ULCC with a draft of 15 meters is moored alongside a berth with 16.5 meters of water => relation water depth/draft = 1.1

Relative resistance factor in case of cross current = 5.6

In case of unlimited water depth a cross current of 1 knot produces a force of 60 tons




In case of a limited water depth (example) this force is increased till 5.6 x 60 ton = 336 ton

This equals 9 steel mooring ropes of 40mm diameter




The relative proportion of the different elements has to be considered

Ballasting decreases the keel clearance but also reduces the lateral wind surface. The wind effect is of greater importance than the the clearance effect (see next slide).


Example of cross and longitudinal forces

18.000 & 70.000 SDWT: Wind 60 knots (30m/s), current 5 knots longitudinal and 1 knot cross current

200.000 SDWT: Wind 60 knots, current 3 knots longitudinal and 1 knot cross current


Conclusions

In ballast condition the most important forces are wind generated

In loaded condition the most important forces are current generated

The total force on the ship (alongships + athwartships) is greater in ballast condition than in loaded condition => influence of the wind is of greater importance


Different materials

3 different configurations

All steel wire ropes (equipped or not equipped with tails)

All ropes are synthetic

Mixed systems (synthetic + steel wire rope)

New materials


Steel wire rope + tail (ralonge de la touline)

Purpose of the tail is to add elasticity to account for change in tidal heights

Always use 8 strands nylon with an MBL 25% > steel wire rope

To protect against chafing cover splice of the tail with leather or plastic

The tail is connected to the steel wire rope by means of a Tonsberg shackle or a Mandal shackle

In case of frequent use tails are changed every 18 months


Steel wire rope + tail

Steel wire rope have a high MBL and are not elastic.

Steel wire rope are stored on winch drums with a manual brake

Steel wire rope are relatively easy to handle up to 40mm ????

Steel wire ropes last longer than synthetic ropes

Price steel wire = synthetic


Tonsberg shackles


Mandal Shackle


Full synthetic mooring configuration

Biggest problem is elasticity

This elasticity can give an important « sway » (balancer) to the ship (breaking out)

3 mooring ropes – different materials – same length (50 m), MBL and load

Steel wire – 0.3m elongation

Polyprop – 5m elongation

Nylon – 8 m elongation


Breaking out


Effect of the hawser elasticity on the restraint capacity

1. Materials with the smallest elasticity take the biggest load

2. Short rope = big load

3. Relation - is not linear



Synthetic fibres loose tensile strength (force de traction) if submitted to cyclic tensions attaining 30 to 50% of their MBL.

Those cyclic tensions are not constant, due to resonance high tensions occure during short periods of time



Because of;

Cyclic tensions

Internal friction

Exposure to the marine environment

Tensile strength of synthetic ropes will diminish after 1 year

Tensile strength of steel wire rope will diminish after 5 years => more durable



Another side effect is sagging (affaissement)

The « sag » is function of;

m-n

Weight of the mooring line

Tension in the line

Water depth (suction effect)



Consequence of the sagging is that a synthetic rope can never be pulled as stiff as a wire rope.

A wire rope will « react » faster on a breaking out of the ship.

A synthetic rope will compensate the the sag before reacting

Max. allowed distance between berth and ship is normally limited to 6% of the water depth


Mixed mooring systems

Mix of wire ropes and synthetic ropes

Certainly NOT the best configuration but the most common one.

If possible use steel wire rope as springs and breasts and use synthetic ropes as head- and stern line


New materials

Composite materials

Expensive but excellent mooring system

Kevlar –Aramid ropes are very strong, light and show little sagging. They react fast in case of breaking out of the ship.


Efficient mooring

The efficiency of a mooring rope depends on the following factors

Material (steel wire or synthetic – elongation & MBL)

Length

Angles with longitudinal and transversal axis in the horizontal plane

Angles with the horizontal in the vertical plane


Function of the different ropes

Head- and stern lines & the springs are stabilising the ship alongside

Breast line will prevent the ship to break free from the berth

Breast lines must be as perpendicular as possible to the ships longitudinal axis

Springs must be as parallel as possible to the berth


Recommendations

The function of springs and breast lines is clear. Springs are preventing longitudinal movement while breast are opposing transversal movements.

The function of head and the stern lines depends on their angle with the longitudinal axis. Great angle => they serve mainly as breast line while small angle => stopping longitudinal movement


Recommendations

The ideal configuration will rarely be achieved.

To obtain a perfect mooring configuration their must be a perfect harmony between the ships equipment and disposition on board and the configuration ashore

Berthing ships is always a matter of compromises


Recommendations

Following recommendations have been published by the OCIMF = Oil Company International Maritime Forum

The recommendations are valid for a tanker moored alongside a T-berth


Recommendations based on OCIMF – Effective mooring

1. The horizontal angles of head-, stern- and breast lines < 15°



2. The vertical angle with the horizontal plane must be < 25°

The effective force is proportional to the cosine of the angle

If the angle is 25° the line is effective for 91%

If the angle is 45° the efficiency is reduced to 71%

=> Springs & breasts must be long enough and not to steep


Springs & Breasts



3. Breast lines are most effective is on the longitudinal axis.

If is 45° we have to increase the force in the breast line till 141 ton to obtain an effective transversal force of 100 ton



4. Springs offer the greatest holding power in the longitudinal direction. Their length is 60 meters



5. The impact of the head and the stern lines on the total holding power of the mooring configuration is less important than the influence of springs and breasts. This mainly because these lines are too long.

Never the less they are important to compensate the dynamical forces.

Length 110m = ½ coil



6. Very short lines must be avoided. They always take the most important part of the load, especially when the ship is moving

Short length = important vertical angle


Short breast lines

Long breast line: 52ton load is sufficient to obtain an effective holding power of 50 ton

Short breast line: Load has to be increased till 88 ton to obtain same result



7. All the mooring ropes in the same group (working in the same direction)must have a same tension. If not, the weakest line will break first. Total load will have to be received by the remaining lines => increased risk of breaking (chain reaction)

Groups are f.i. aft spring + head lines, Stern lines + forward spring, breast lines



8. Their must be an equilibrium between the 4 groups (head- and stern lines, springs and breasts.

Example: Optimal mooring configuration is determined after studying the static and dynamical forces for a specific berth.


Mooring example

Maximum breaking out from the berth = 1 meter

Direction of the wind: 110° -> 290°

Frequency 58%

25.2% 3 à 4 Beaufort

0.65% > 8 Beaufort

Proposed configuration all nylon 80mm (MBL 110 ton): 4 breast lines (aft) + 1 stern line

3 headlines + 3 breast lines (fore)

The fore ship will resist a wind pressure of 32 knots while the stern will resist a wind pressure of 33 knots => The berth will be operational till 7 Beaufort => not operational 5.8% per year

The configuration of the berth is not ideal since the horizontal angles > 15°



9. The number of lines is function of the size of the ship and the prevailing weather conditions

A – Panamax (75.000 dwt) - 12 lines (2 headlines – 4 breasts – 4 springs – 2 stern lines: 2 –2 – 2 fore and aft)

B – VLCC (150.000 dwt) 16 lines (4 headlines – 4 breasts – 4 springs – 4 stern lines: 4 –2 – 2 fore and aft)


A – Panamax & B - VLCC


Mooring configurations bulk carriers

Cape Size: 4 –2 – 2 (fore and aft)

Panamamax: 4 –1– 1 (fore and aft)

Handy Size: 4 –1 (fore and aft)

Mini Bulker: 3 –1 (fore and aft)

Mini Bulker – moored so it can shift forward and backwards during loading/discharging


Mooring configurations bulk carriers



10. Mooring lines must be passed ashore using the deck fittings (fairleads) because of friction and the curvature relation.

Curvature relation = curvature deck fitting/ mooring line

In case of a mooring wire relation has to be > 20 to reduce loss in tensile strength


Mooring configuration –concentrated on the fore ship

Deck fittings (accessoires de pont)

OCIMF equipment: Panama hawse- hole Pedestal Fairleads (Chaumard)


Info

Suez & Panama Canal


Suez Canal

Total length is 190.25 km

Water surface width is 280.345 m

Width between the buoys is 195.215 m

Canal depth is 22.5 m

Maximum ship draught allowed is 62ft

Speed allowed for loaded carriers is 13 km/h

Speed allowed for unloaded carriers is 14 km/h.

Average transit time is 14 hours

Suez Canal


Panama Canal

The Panama Canal is approximately 80

kilometers.

The Canal uses a system of locks

The locks function as water lifts: they raise

ships from sea level (the Pacific or the Atlantic)

to the level of Gatun Lake (26 meters above

sea level)


Panama Canal

Each set of locks bears the name of the townsite where it was built: Gatun (on the Atlantic side), and Pedro Miguel and Miraflores (on the Pacific side).

The maximum dimensions of ships that can transit the Canal are: 32.3 meters in beam; draft 12 meters in Tropical Fresh Water; and 294.1 meters long

The narrowest portion of the Canal is Culebra Cut


Panama Canal


Gatun Lock

Gaillard Cut


Pedro Miguel Locks


Mira Flores Locks

4-roller fear lead Towing Bracket


Smit Towing Bracket


Chocks and buttons


Bits and Bollards


Panama chocks


Roller Chocks


Roller Fairleads


Towing pads (point d’attache pour le câble de remorque)


Emergency Towing Systems

SOLAS Requirement

Regulation Chapter II-1, A-1, 3-4

Since 1996, January 1, all tankers exceeding,

20,000 DWT are to have an emergency towing

arrangement fitted at the aft and forward. This

IMO resolution MSC35(63) which covers the

installation of emergency towing arrangements

on tankers was decreed after the unfortunate

disaster of the MV Braer in 1993.


Emergency Towing Systems - Aft beneath deck


Emergency Towing Systems Typical Arrangements Fwd


Demo

C:/Documents and Settings/Kris De Baere/Local Settings/Temporary Internet Files/Content.IE5/XUZN2K44/optimoor/OPTIMOOR.exe

C:/Documents and Settings/Kris De Baere/Local Settings/Temporary Internet Files/Content.IE5/XUZN2K44/OPTIMOOR.exe


Mooring alongside a classic berth (quay)



Different methods – see lab ship’s technique

Practical techniques – see lab ship’s technique


Mooring alongside a T-berth


Mooring with 2 anchors


Ship to ship


SPM – Single Point Mooring Buoy


SPM - buoy


FPSO – single point mooring


FSO - operations


STL – Submerged Turret Loading


STP – Submerged Turret Production


Safe fibre ropes

1. Ropes should be covered when they are not being handled, and stowed away when not in use at sea, to prevent contamination by oils and chemicals, and degradation by sunlight.

2. Ropes must be kept away from heat, oil, paint and chemicals.

3. Ropes should be stowed on gratings for ventilation and drainage.

4. Ropes must be examined regularly for wear, stranding, melting and powdering, and replaced if serious defects are found.


Safe Wire Rope

1. Wires should be lubricated regularly with an approved lubricant.

2. Everyone who handles wires should wear leather -palmed gloves to protect their hands from snags.

3. Wires must be examined regularly for wear, stranding, dry core, kinks, and excessively flattened areas. They must be replaced if the number of broken strands (snags) exceed 10% of the strands in any length equal to eight diameters, or if any other serious defects are found.


Safe line handling – see lab

1. Flake out all mooring lines on the deck, clear, and ready to send. This will ensure that any fibre lines which have become buried on reels can be freed in advance, when there is less likelihood of accidents. Do not use a wire direct from a reel designed only for stowing.

2. Have all necessary heaving lines, messengers, tails and stoppers available at the mooring station, and rat guards ready for use.


Flaking out mooring lines

Lover les aussières à la française

De trossen zijn klaar gelegd in franse bochten

To avoid that someone puts his foot/feet in a loop


Safe position between mooring ropes

Position yourself away from the whip


Putting the mooring rope on the warping head of the winch

The anchor winch has maximum power when it runs in the sense of picking up the anchor (anti-clock wise)



3. Have sufficient crew available.

4. All crew should wear safety helmets and safety shoes, and have no loose clothing which could become entangled in the winches or trapped by the lines. Gloves should be tight fitting, to reduce the risk of becoming trapped by lines, and should have a leather palm to protect the hand against abrasion and prevent wounds caused by snags of wires; they should provide adequate insulation in cold weather.



5. When one seaman is handling a line on a drum end, he should not stand too close to the drum to avoid being drawn in. There should be an additional seamen whose duty is to clear the loose line when heaving, and supply the loose line when slacking.

6. The person operating the winch controls should have a clear view of the entire area including any seaman handling lines with that winch.


Traditional stopper

A traditional stopper using a single line may be used only on a mooring line made of natural materials, as shown below, but such mooring lines are no longer common on board ship



15. Stand well clear of all lines under tension. This means everybody, not just those handling that line.

16. Synthetic fibre ropes may break without warning, and the resultant whiplash may cause severe injuries or even death.

17. Synthetic fibre mooring ropes should be stoppered using two tails of fibre rope, halfhitched under the mooring rope, with the two free ends criss-crossed over and under, as shown in the diagram below: (This is sometimes known as a Chinese stopper.)



18. Mooring wires should be stoppered using a chain stopper with a well-spaced cow hitch (Lark’s head)(Deux demi clefs renversées)(it is recommended that the two hitches are at least 25 cm. apart) and with the remainder of the chain and its rope tail turned up several times against the lay, as shown in the diagram below. The cow hitch is used because it is easily pulled loose when no longer required, a clove hitch (mastworp -Deux demi clefs à capeler (noeud de cabestan)) is likely to jam.


Chain stopper

Safe mooring

1. All operations must be carried out ONLY under the direct orders of the supervising officer.

2. The supervising officer must ensure that communications with the bridge are -CONTINUOUSLY maintained. If using radios all calls should start with the ship’s name (to avoid confusion), and then the caller should immediately identify himself and who he is calling to avoid confusion on one’s own ship A spare fully-charged battery should be carried whenever portable radios are used. A back up system must be readily available at all times.


Safe mooring

3. Check with the bridge before sending the first lines, and before making any lines fast.

4. Keep the bridge informed of distances off the quay, any obstructions and other moored ships, lighters or other floating objects.

5. Advise the bridge if there is any possibility that a slack line may become entangled in the propeller - or thrusters.

6. Warn the bridge if any lines become excessively taut.


Safe mooring

7. Make fast and cast off tugs only on orders from the bridge.

8. When heaving lines are being thrown, ensure that all personnel ashore and on board are alerted, and stand well clear.

9. The supervising officer must make sure he can always see both the winch operators and the particular line when giving orders for adjusting the tension in a line.


Safe mooring

10. Secure the lines as per the Master’s orders. i.e. which lines to leave on the drums, which lines to make fast on bitts, Which lines to leave in auto/self-tension, if any, and what level to set the controls.

11. Ensure rat guards are properly fitted to all lines.

12. The supervising officer must remain at the mooring station, with his full crew, until he is dismissed by the Master.


Plague Control ?

Deratisation

Rat guards


Self Tensioning Winches

Self tensioning winches can be set to a certain holding force. If this value is exceeded, then the winch automatically adjusts the length of wire to the new force (too much holding force: slacking; too little holding force: heaving). This system is frequently used by ships that load and discharge quickly (container ships and Ro-Ro-vessels) or if there is a large tidal range in the port.



1. Control lever for the

winch

2. Cooling fan

3. Control for the self-

tension setting



The heaving power of a winch is always lower than its

render force. This means that if a winch is left in self-

tension, and the external forces increase, the line will pay

out, and it may not be possible to heave it in again until

such external forces reduce. Also, the render force of the

winch is much less than the holding power of the brake

Self-tensioning winches at opposite ends of the ship can

work against each other, so that the ship can sometimes

‘walk’ along the berth, when an external force is applied

at one end.



Hence it is recommended that mooring lines are NOT left

in self-tension once the ship is secure alongside. With

short breast lines in fair weather, these controls may be

useful during rapid load/discharge operations. However,

those winches which are directly counteracting any

external forces must be left on the brake.

Self-tensioning winches are useful during berthing

operations with reduced manning, as once the line is

ashore and the controls set, they will reel in any slack,

maintain the tension in the line, and prevent the line being

damaged through excessive strain.


Keeping moorings taut

The OOW must ensure that the mooring lines are kept sufficiently taut at all times to keep the ship firmly alongside. At rapid loading or discharging berths, the Chief Officer may assign additional crew to assist the OOW, as the operation of adjusting the lines may have to be done frequently. The 00W must never attempt to adjust a mooring line by himself, unless it is permanently wound on its own drum.

If the lines are not in equal tension, they may part in succession if the ship is subject to exceptional high forces, such as very strong winds, large swells or water surges from other ships passing too close and/or too fast.


Keeping moorings taut

Brake linings can lose their grip when oil and rust are present, and are susceptible to loss of holding power during periods of rain or high humidity.

The OOW should remember to adjust any fire wires as the ship’s freeboard changes, to ensure that their ends remain clear of the water.

It is essential for the OOW to check the moorings when other ships are arriving at or leaving from the berth immediately ahead or astern of their ship.

It is good practice for the OOW to be in attendance forward or aft whenever the adjacent ship is arriving or sailing to watch out for contact damage, or other incidents, in addition to monitoring the moorings.

Fire wire Strong steel wire

1 end is put on a bollard

Other end is hanging overboard +/- 1 meter above the water

The outer end is held in position by means of a weak line.

Middle part is flaked out on deck

In case of fire a tugboat can grab the outer eye and pull the tanker free of the berth


Excerpt from terminal rules and regulations - Saoudi Arabia

TOWING-OFF WIRES OF ADEQUATE STRENGTH AND CONDITION MUST BE MADE FAST TO BOLLARDS ON THE TANKER. FORWARD AND AFT, AND THEIR EYES RUN OUT AND MAINTAINED AT OR ABOUT THE WATERLINE. THE WIRES MUST BE OVER THE OFFSHORE SIDE. IN ORDER THAT SUFFICIENT WIRE CAN BE PUT OUT TO ENABLE THE TUGS TO TOW EFFECTIVELY, ENOUGH SLACK MUST BE RETAINED BETWEEN THE BOLLARD AND CHECK AND PREVENTED FROM RUNNING OUT BY A ROPEYARN OR OTHER EASILY BROKEN MEANS


Chafing (Frotter – Raboter)

The OOW must check the moorings at least hourly during

his watch, not only to ensure they remain taut but also to

look out for chafing, where the rope rubs against an

obstruction, and may part. This may occur when the ship

is surging back and forth along the quay due to a large

swell, or when there is excessive movement of a mooring

buoy. Synthetic fibre ropes possess very low resistance to

chafing when under load; the friction generates heat

which causes them to melt and fuse, and the rope is then

permanently weakened, and may part quite quickly.


Chafing (Frotter – Raboter)

Ropes may chafe by rubbing against each other, or

against the ropes of another ship. The officers on stand-by

fore and aft during mooring operations must be alert for

this when sending ropes to different bollards ashore

through different leads on board. If they notice any

chafing, they should have that line removed and sent from

a different lead. Short leads with substantial dips are

prone to chafing on the ship’s structure.


Chafing

Sometimes a change in freeboard, or some external

factors such as a change in the sea state, may cause lines

to start chafing. If he notices any chafing, OOW must

clear the obstruction, change the lead of the mooring

rope, or wrap the rope in canvas or some other material

to bear the rubbing and wearing away action. The outside

of the canvas may be greased to reduce the friction, but

this grease must not be allowed to remain in contact with

fibre ropes as it will cause them to deteriorate. The OOW

must always advise the Chief Officer of his observations

and actions.


Emergencies

Occasionally unexpected changes of load may cause the brakes of the mooring line drums to slip, and the vessel is at risk of moving off the berth. DO NOT RELEASE THE BRAKES AND ATTEMPT TO HEAVE THE SHIP BACK ALONGSIDE USING ONLY THE POWER OF THE WINCH.

The recommended action is:

1. If the winches are in self-tension apply the brakes IN ADDITION.

2. If the brakes are in use, tighten them, put the winch in gear and heave on as many lines as possible.


Emergencies

3. Inform the senior officers, and seek extra crew assistance

4. Summon tug assistance if necessary.

5. Consider reducing the freeboard by ballasting.

6. The OOW should remember that brake holding power is always greater than winch heaving power, but that the two together increase the load.

For example:

Winch render force = 35 tonnes.

Brake holding power = 65 tonnes.

Total holding power = 100 tonnes.


Emergencies

He should be careful this does not exceed the breaking

strain of the rope, or the safe working load of the leads

and rollers. However, in an emergency it will usually be

preferable to endeavour to hold the ship in position and

risk breaking the lines.


Mooring equipment ashore


Equipment ashore

Bollards and bitts

Winches - capstans

Quick release hooks

Laser docking systems

Mooring line monitoring systems

Fenders


Bitts and bollards


Capstans


Quick Release Hooks

The basic starting point to any integrated

mooring system

Can be released manually or (electric,

hydraulic or telemetry) and can

incorporate load pins for optional

multipoint computer-based remotely

mooring line tension monitoring systems


Quick Release Hooks


Quick release hooks

Explosion proof double hook unit

Quad. hook with load monitoring and remoter release system


Mooring Line Monitoring System

The vessel Mooring Line Monitoring system (MLM), provides real time monitoring of all mooring lines and warns of excessive or out-of-range loads.

Changing weather conditions or current loading can cause unequal load sharing within the mooring system. This can lead to potential failure of mooring lines and damage to jetty


Mooring Line Monitoring System

Load on the hooks is measured by load pins

Data is transferred to the jetty control room

Data is completed with environmental data and data concerning the movement of the ship alongside


Environmental data

Data is collected by a buoy and presented on graphic display



The primary benefit of a Docking Aid System

or DAS is the provision of real time data of the

vessel’s position and progress relative to the

jetty by measuring distance from the jetty and

speed of approach in the critical 0 to 200

meters zone.

With this data the vessel’s master and pilot

can better direct tug and shipboard personnel

in the safe manoeuvring of the vessel towards

the jetty and minimize any potential for

damage to the berth



Typically, two sensors are located on the jetty measuring distance to bow and stern sections of the ship.

This together with average speed are captured at the jetty control unit and displayed to the ship and mooring crew on wireless monitor, computer screen or jetty mounted display board, as required.

Earlier systems used radar sensors, however today laser sensors are the most reliable technology employed for vessel docking.


Docking systems – GPS based f.i. e-fix system

Ship trials (speed and manoeuvring)

Oil and gas tanker approaches and docking operations

SPM/FSO Docking and Drift Warning

Oil rig positioning

Navigation of ships into locks & docks

Ferry operations



It should be noted that the E-Sea Fix system can be

integrated into existing Laser Docking Systems.

All data from an existing Laser Docking System

(such as environmental data, load arm monitoring,

mooring load monitoring and drift warning

information) can be relayed and displayed on the

pilot monitor.

A receiver is capable of receiving signals from both

the US constellation as well as the Soviet based

GLONASS constellation. This dual constellation

ensures that the number of satellites visible to the

receivers is maximised.


Accuracy

Speed accuracy better than any ship’s

log, ± 1 cm per second i.e. ± 0.02 knots

Heading accuracy better than any gyro

system, approximately ± 0.01 degree

Rate of turn better than any rate gyro

system, approximately ± 0.02

degree/second and up

Position accuracy to a few centimetres



Signal is used as input for an ECDIS based on C-map or S-57 maps.

Portable version exists


Berth management systems

A « Berth Manager» monitors the vessel

approach, mooring load and environmental

situation in a single integrated system, with a

range of optional displays, readouts and

functions, and provides the port operator with

comprehensive reporting on the behaviour of

vessels while in the confines of the port. The

system assists the docking procedure and

monitors mooring performance.


Berth management systems


Fenders

Used to:

Divide the load

Protect the berth

Protect the ship

Fenders can be fixed or mobile


Yokohama Fenders


Fixed fenders


Mooring equipment on board


Mooring equipment on board

Heaving line (ligne d’attrape)

Messenger (grelin)

Tails


Heaving line (ligne d’attrape)


heaving line (Ligne d’attrape)


Messenger - grelin


Tail (allongement de la touline)


Passing ropes ashore

Before arriving at the dock all crewmembers should put on their Personal Protective Equipment and move out onto the deck. All lines should be prepared for docking making sure that they will feed out freely.

There should always be someone on the dock to receive the line.

Do not attempt to throw the line to the bitt.

If the boat is to be moored some distance from the dock a messenger line (grelin) with a monkey’s fist can be thrown and then hauled in to transfer the mooring line safely to the dock.



If you are sharing the bitt or bollard with another

vessel feed the eye of the mooring line through the

eye of the line already on the bitt and then place the

eye over the bitt.

This will allow you or the other vessel to quickly

remove a line without disturbing the remaining line.


Putting 2 ropes on the same bitt

1.Wrong

2.Correct

The « other » ship can leave without disturbing our mooring configuration



While handling lines you must be very conscious of

the placement of your hands and feet in proximity to

the line. Never put your hand in the bight of the line

at the bitt, and watch that you do not step into the

bight of the line on the deck with your foot. If the

boat surges you can be caught in an instant,

resulting in serious injury or death.



Never place yourself in

a position where the

line can pinch you up

against the bulwarks or

equipment on deck.

You will never be able

to move quick enough

to get out of the way or

have the strength to

keep the line off you!

145292848 Mooring of Ships Forces 2

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Transcript of 145292848 Mooring of Ships Forces 2