1. PROPULSION (PROPELLER + RUDDER) 2. ANCHOR 3. BOW THRUSTER (IF FITTED) 4. Tug and mooring lines

1. WIND 2. CURRENT 3. SEAS AND SWELL

SHALLOW WATER SHIP / BANK INTERACTION

WHAT INFORMATION IS AVAILABLE FROM THE SHIPS MANEOUVRING DATA?

Turning circle data Stopping distance table Speed / RPM Table Thruster characteristics if fitted Conditions of weather for which above data is applicable

TURNING CIRCLE DATATransfer

Advanc e Tactical Diameter

Final Diameter

TURNING CIRCLE DATAAdvance: The distance traveled by the centre of gravity along the original course (on the fore and aft line).

TURNING CIRCLE DATATransfer: the distance the vessel moves perpendicular to the original course during the turn. i.e distance traveled by the centre of gravity, measured from the original trace to the point where the vessel has altered her course by 90 degrees.

TURNING CIRCLE DATATactical Diameter: Is the transfer for 180 degrees.

TURNING CIRCLE DATADrift Angle: The angle between the ships fore and aft line and the tangent to the turning circle.

The vessel turns with its bow inside and stern outside the tangent to the path of its PIVOT POINT centre of gravity.Drift Angle

The angle between the tangent to this path, the turning circle and the centerline

TURNING CIRCLE DATAWhich part of the vessel makes the turning circle? The PIVOT point

The PIVOT POINT is the point at any instant during the turn, where the line drawn from the centre of curvature of the path meets the ships fore and aft line.

PIVOT POINTPIVOT POINT WHEN SHIP IS STOPPED COINCIDES WITH THE SHIPS CENTRE OF GRAVITY APPROXIMATELY AMIDSHIPS.

COG

Pivot Point

PIVOT POINT WHEN MAKING HEADWAY TWO FORCES COME INTO PLAY FORWARD MOMENTUM OF THE SHIP. LONGITUDINAL RESISTANCE TO FORWARD MOMENTUM CREATED BY THE WATER AHEAD OF THE SHIP. AS A ROUGH ESTIMATE AT STEADY AHEAD SPEED THE PIVOT POINT SETTLES SOME WHERE BETWEEN AND 1/3rd OF SHIPS LENGTH FROM FORWARD.

PIVOT POINT

PIVOT POINT When making sternway the opposite happen and at steady astern speed. The pivot point settles somewhere between 1/3rd and 1/4th of the ships length from the stern.

TURNING CIRCLE DATANow that we know that the pivot point is the one making the turning circle. Do you know for how many turning circles the data is available on the ships maneouvring booklet.

MANOEUVRING STANDARDSIMO Manoeuvring Standards (Resolution MSC.137 (76), 2002)Turning ability Initial turning ability Yaw checking ability & course-keeping ability Stopping ability

Are the IMO Manoeuvring Standards & the Criteria good measure for safe navigation at sea ?

1. Turning circle Advance < 4.5 ship lengths Tactical diameter < 5 ship lengths

1. Zig-zag test Initial Turning Ability 100 rudder angle, a 100 heading change in less than 2.5 ship lengths. Yaw-checking and course keeping ability Overshoot angle < 250 in a turn when 200 rudder

Turning AbilityThe advance should not exceed 4.5 ship lengths and the tactical diameter should not exceed 5 ship lengths in the 35 degree turning circle manoeuvre.

Turning ability indices from sea-trial (Quadvlieg et al 2003)

Initial Turning AbilityWith the application of 10 deg. Rudder angle to port/starboard, the ship should not have traveled more than 2.5 ship lengths by the time the heading has changed by 10 deg. from the original heading.

Initial turning ability indices from sea-trial (IMO DE 34/WP.7, 1991)

Yaw checking & Course-keeping ability Ship should not exceed the values of the first and secondovershoot angle (solid line in the figures) in the 10/10 zig-zag test & 25 of the first overshoot angle in the 20/20 zig-zag test

(a) 1st overshoot angles of 10/10 zigzag test

( b) 2nd overshoot angles of 10/10 zigzag test

(c) 1st overshoot angles of 20/20 zigzag test

Yaw-checking & course-keeping abilities indices from seatrial. (IMO DE document by the Netherlands 2000)

1. Stopping Distance Crash stop The track reach should be < 15 ship lengths At the Administrations discretion Large Displacement vessels could be allowed to have a max track reach of upto 20 ship lengths

Stopping The track reach in the full astern stopping test should not Abilityexceed 15 ship lengths. However, this value may be modified by the Administration where the ships of large displacement make this criterion impracticable, but should in no case exceed 20 ship lengths.

Track reach of ships at full load condition (IMO DE 44/4 2000)

Stopping Ability

Appendix 3 on Stopping ability of Very Large Ships (MSC/Circ. 1053)

Prediction of stopping distance by the expression in the MSC/Circ.1053 (IMO DE 47 2004)