SHIP HANDLING - I

Prof.Dr. Yusuf ZORBA

SHIP HANDLING�/�Ship Maneuvering

Course Objectives

• To understand theory and meaning of ship handling and effecting factors for the ship handling operations,
• To understand resistance forces of ship movement, ship forces and their effects on the ship,
• To understand the theory and effects of turning circle, shallow water, squat and narrow channel

SHIP HANDLING

Learning Outcomes of the Course

1. Having knowledge of theory related to ship manoeuvring
2. Understanding usages of the force sources on the ship manoeuvre
3. To understand importance of planning of the ship manoeuvre depends on the effects of the forces
4. To develop to extrapolate preventive commands
5. To find theoretical solutions for manoeuvring problems according to related regulations

SHIP HANDLING

• Design is highly influenced by commercial and economic consideration of the various shipping trades. The handling characteristics are therefore NOT a PRIMARY CONCERN for the ship designer.

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«A body immersed in a fluid is buoyed up by a force equal to the weight of the displaced fluid».

Archimedes

SHIP HANDLING

• Handling any vessel means;

performing necessary movements for successful, and safe result in an optimum time

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• Many masters develop ship handling as 'art' whereby they instinctively respond and react to the movement of the ship, without the full understanding of the science behind those reactions and reason for their need.

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• There is no doubt that ship handling requires a lot of practice, however, good theoretical knowledge about the ship and its surroundings is highly recommended for anyone intending to master the art.

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Proactive vs Reactive

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Understanding of the science (theory) of ship handling will help ship handler to be more proactive instead of being only reactive

SHIP HANDLING

• A natural ship handlers is a person borne with the ability to make his ship do exactly WHAT he wants WHEN he wants.

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• Most of us must learn the art of ship handling by studying the theory of ship handling and backing that up with practice onboard, under safe supervision.

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• The art of ship handling involves the effective use of forces under control to overcome forces not under control.

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Charles H. Cotter, The Master and His Ship

SHIP HANDLING

• Moving a vessel in an intended way by commanding

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• Ship handling is «to use of forces effectively»

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• Ship handling is «the effective use of ship forces against the effects of uncontrollable forces and environmental forces».

SHIP HANDLING

«Truth is ever to be found in simplicity, and not in the multiplicity and confusion of things»

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Sir Isaac Newton PRS (25 December 1642 – 20 March 1726/27^[a]) was an English mathematician, physicist, astronomer, theologian, and author (described in his own day as a "natural philosopher") who is widely recognised as one of the most influential scientists of all time, and a key figure in the scientific revolution. His book Philosophiæ Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy), first published in 1687, laid the foundations of classical mechanics. Newton also made seminal contributions to optics, and shares credit with Gottfried Wilhelm Leibniz for developing the infinitesimal calculus.

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SHIP HANDLING

• Motion, in physics, change with time of the position or orientation of a body.
• Motion along a line or a curve is called translation.
• Motion that changes the orientation of a body is called rotation.
• In both cases all points in the body have the same velocity (directed speed) and the same acceleration (time rate of change of velocity).
• The most general kind of motion combines both translation and rotation.

SHIP HANDLING

• In physics, a force is any interaction that, when unopposed, will change the motion of an object.

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• A force can cause an object with mass to change its velocity (which includes to begin moving from a state of rest), i.e., to accelerate.

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F = m . a

• «m»in the formula shows the ship displacement value,
• In addition, «added mass» is defined as the amount of power needed to change the speed of the ship, which is indicated in relation to the acceleration / deceleration of the ship.
• The third rule can be stated as the effect of internal and external ship sources and underwater resistances. (Wind, Current, Propeller, Rudder, Tug, Wave Resistance, etc.)

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SHIP HANDLING

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• The art of ship handling involves the effective use of forces under control to overcome forces not under control.

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Charles H. Cotter, The Master and His Ship

SHIPHANDLING

SHIPHANDLING

The Forces Acting on the Ship (*)

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1. Wind
2. Current
3. Tides
4. Surges from passing ships
5. Waves / swells
6. Ice
7. Changes in draft, trim or list

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*MEG: Mooring Equipment Guidelines

SHIP HANDLING - I

Prof.Dr. Yusuf ZORBA

«Full speed is FOOL speed»

SHIP HANDLING

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• Handling any vessel means;

performing necessary movements for successful, and safe result in an optimum time

SHIP HANDLING

1. Safety:

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• Inconvenient environment (Environmental Factors)
• Limitations of the ship (Technical Failures):

Length, Breadth, Depth/Draft, Deadweight, Displacement, Block- Coefficient, Coefficient of fineness, Wind Draft, Under Keel Clearance at relevant time, Weight-Power Ratio, Horsepower of Engines, Type of Engines, Speed, Number and type of propeller(s), Type of rudder, If fitted with lateral thrusters or not. Type, quantity and disposition of cargo and/or ballast.

• Incompetency of the master /pilot (Human Factor):

Level of adequate seamanship knowledge and experience, Learning theory and basics of ship handling, Level of practical knowledge of ship handling, Gaining experience of ship handling by actual maneuvers

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2. Suitable time:

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a) Fast and safe manoeuvring may complete with the optimum slow speed

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3. Success:

• intended results achieved without delays,
• w/o damages, and
• w/o accident, case

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Ship handling in practice can be said to be a circular movement between observing, estimating, assessing, deciding and executing.

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Relevant and up-to-date information is essential for the ship handler:

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A ship’s ability to manoeuvre

depends on:

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• The ship’s steering ability
• The ship’s turning ability
• The ship’s stopping ability

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Important qualification – necessary for the professional ship handler – is an ability to think and planning AHEAD of the ship, thus being, at all times prepared for the NEXT MOVE.

SHIP HANDLING

• Ship Manoeuvring Characteristics
• Displacement comprises the ship’s light weight and its deadweight, where the deadweight is equal to the ship’s loaded capacity, including bunkers and other supplies necessary for the ship’s propulsion.

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• The deadweight at any time thus represents the difference between the actual displacement and the ship’s light weight, all given in tons:

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• deadweight = displacement – light weight

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LPP = 0.97 × LWL

SHIP HANDLING - I

Prof.Dr. Yusuf ZORBA

«Full speed is FOOL speed»

SHIP HANDLING

• Size of ship

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• Large ships are designed for ocean passages (1950’s)

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• There is no direct relation between Engine power and the size of the ship. For ex: a 50000 dwt ship does not necessarily need an engine double the size of the one on a 25000 dwt ship

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• Size of ship
• Larger vessels stops harder!!!

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Ship A Ship B

150 meter 180 meter

35.000 dwt 55.000 dwt

6000 kwh 8500 kwh

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Faster and more powerful…

However; requires much more distance for manoeuvring

SHIP HANDLING

• Size of ship
• Larger distance

=> Slower motion

=> Less control of steering

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Ex: High location of the bridge on large vessels makes it harder to estimate the ship’s speed

• Losing communication with bow and/or stern stations during manoeuvring
• => not getting distance info
• => panic
• => ???

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• Size of ship
• Approach of vessel towards dock faster than intended may cause damage. The damage will be greater on a larger ship than a smaller ship with same moment.
• Effects of wind forces during manoeuvring=> control of the ship

SHIP HANDLING

• Size of ship
• On long ships, different intensity of wind forces on fore and aft greatly effect manoeuvring.
• Ex; in river ports vessel’s bow caught in the current and aft stay in the still waters will swing the ship very fast and, in these situations, tugs are very useful

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• Large/Big Ship ???
• VLCCs do not need any description, not comparable
• 20.000 DWT ship is a large ship in comparison
• In 1950’s 45.000 DWT ships were large ships
• All these vessels are large when compared with smaller

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• Large ship ???

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• Length is sometimes more descriptive speaking of “large” than DWT
• 100m and less is usually considered small and 200m and more is large
• In-between may be considered as large or small

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• Large ship ???

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• Port specifications also effect the description of “large” vessel. 5 000 DWT vessel is a large vessel for a port handling 500 DWT ships. On the other hand same ship would not be considered large for a port handling 50 000 DWT ships
• On-time desicion-making is more critical for large vessels in risk of collision

• Super Tanker’in Özellikleri 
• Name : Jahre Viking (Knock Nevis)
• IMO No : 7381154
• Ex : Happy Giant, Seawise Giant
• Built : 12/1976
• Type : Tanker
• Flag : Norway (NIS)
• DWT : 564,761 ( After reconstructing )
• Draft : 24.61
• Builder : Sumitomo H.I. (1016)
• GT : 236,710
• LOA : 458.45
• Owner : Ferd Olsen
• NT : 285
• Beam : 68.86
• Depth : 29.80
• Cubic : 658,362

SHIP HANDLING

• Ship design and maneuvering
• Longitudinal location of the bridge on ships play critical role in manoeuvring; aft, midship, or fore ward.
• Each location has their own advantage and disadvantages. The important thing is to be aware of these advantage and disadvantages and use them correctly.

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SHIP HANDLING

Bridge on aft

• Preferable for most pilots
• Most of the ship is visible
• Possible to determine the ship’s way of swing and where it will stop
• In contrary, it is hard to determine the position of the bow and distances from the bow (especially when anchoring).

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• Bridge on aft
• There is a greater blind sector. Fast small crafts, yachts, etc. may be lost in sight easier
• Calculations for collision avoidance may be effective on the bridge however on the fore side there may be a risk of collision continuing
• Keeping a sufficient distance fore ward of the bow (decreasing speed) would be effective for collision avoidance in fog

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• Bridge on foreward of the ship
• Has great advantages when approaching and anchoring
• Advantages in fog and narrow entrances
• May be harder to determine which side of the ship are the objects ahead on the bow (as in starboard or port)
• Adaptation and decision-making in situations when making turns inside docking areas may be more confusing

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• Bridge on midship
• Advantage of being on the pivot point of the vessel
• Best location for small vessels if the bow and the stern is visible
• Comparing with the challenging manoeuvres of large vessels, on small ships visual communication between manoeuvring stations is very important as an advantage
• Generally, it is not quite possible to discuss about the advantages and disadvantages of bridges on midship
• Higher superstructures on this type of vessels will cause the ship to get more effected by the wind forces

SHIP HANDLING

• Container vessels
• Usually have their bridges located on the aft
• It is quite hard to determine the distances because of the high structures
• Visibility of other ships may differ
• Hight of cargo on low super structured ships may affect visibility

SHIP HANDLING

• Ro/Ro vessels
• Most effected ships by the wind because of their high freeboard
• They require supportive forces since they can get out of control easily without tugboats
• Bridge wings are used to be able to see the stern which lessen situational awareness for the rest of the vessel

SHIP HANDLING

• Ro/Ro vessels;

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• RoPax (RoRo/Passanger)
• ConRo (RoRo/Container)
• RoLo (Roll-on/Lift-off)
• LMSR (Large, Medium Speed RoRo)

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SHIP HANDLING

• Passenger vessels
• Best manoeuvring capabilities
• Easy to observe motion of the ship on all aspects
• Engine is easily controlled and response fast since they are built for speed
• Usually have twin propulsion which is an advantage for ships with large scale and less engine power

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SHIP HANDLING

According to environmental factors, using our forces harmoniously and perfectly, within safety, and in a suitable time, successfully; berthing, unberthing, docking, anchoring, turning, etc. all operations into like a narrow water, open sea, etc. under all situation of sea called a scientific ship handling.

SHIP HANDLING - I

Prof.Dr. Yusuf ZORBA