Investigatory Project for Class 12 CBSE. The project is on the topic : Prism to calculate the refractive index of the prism and its minimum deviation angle.
Chapter 21 (Angle of Loll)
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Maquinaria AlgledozerDescripción completa
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a full turning report for mechanical engineersFull description
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Turning TorsoDeskripsi lengkap
drawings of turning torso tower
Angle Horizontale en topographies
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penelitian anode heel effectFull description
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tap into your inner power philosopher notes
Struktur Bentang Lebar dan Bangunan Tinggi
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Struktur Bentang Lebar dan Bangunan TinggiDeskripsi lengkap
Increase in draught due to list / heel
Learning Objectives
Explains angle of heel due to turning and the effect on stability Calculates angle of heel due to turning Explains increase in i n draught due to list / heel Calculates increase in draught due to to list / heel hee l
Jul 2006
Definitions
Advance
This is the distance travelled by the ship's centre of gravity in a direction parallel to the ship's initial course. It is usually quoted for a 90° change of heading.
Definitions
Transfer
This is the distance travelled by the ship's centre of gravity in a direction perpendicular to the ship's initial course. It is usually quoted for a 90° change of heading..
Definitions
Tactical diameter
This is the distance travelled by the ship's centre of gravity in a direction perpendicular to the ship's initial course when the ship has altered its course by 180° and is on a reciprocal heading.
Definitions
Steady turning circle radius
This is the steady radius of the turning circle when a steady rate of turn is achieved. This state is usually achieved by the time the ship has altered course between 90° and 180° however this will vary from ship to ship..
Definitions
Yaw
This is the angle between the ship's fore and aft line and the direction of travel of the ship's centre of gravity at any instant during the turn.
FORCES THAT CAUSE THE SHIP TO HEEL DURING TURNING
Consider a ship turning to starboard. When the rudder is put over the thrust on the starboard face of the rudder has an athwartships component F which acts at the centre of pressure P of the rudder An equal and opposite force, F1 arises, resisting the athwartships motion set up by the force on the rudder.
FORCES THAT CAUSE THE SHIP TO HEEL DURING TURNING
This reaction acts on the port side at the centre of lateral resistance (CLR) and is located at the geometric centre of the underwater longitudinal area and is invariably higher than P. The two forces, F at P, and F1 at the CLR set up an inward heeling couple for which the moment is given by: F x PQ
FORCES THAT CAUSE THE SHIP TO HEEL DURING TURNING
Once the ship has achieved a steady rate of turn, the inward heel is overcome by the effect of the centrifugal force acting outwards through the ship's centre of gravity (G). This causes the characteristic outward heel to develop in the turn. The centrifugal force is given by: • 'W' is the ship's displacement in tonnes; • 'V' is the speed of the ship in metres per second; • ‘g' is the acceleration due to gravity (9.81 rn/s"), and; • 'R' is the radius of the turning circle in metres.
FORCES THAT CAUSE THE SHIP TO HEEL DURING TURNING
The centrifugal force is opposed by the equal and opposite centripetal force acting through the CLR, where the CLR (for purpose of formula derivation) is assumed to be at the same height above the keel as the centre of buoyancy, B.
FORCES THAT CAUSE THE SHIP TO HEEL DURING TURNING
The initial inward heeling moment is overcome by the outward heeling moment created by both the centrifugal and centripetal forces. If the initial inward heeling moment is ignored, the ship will heel outwards to an angle of steady heel (θ) when the outward heeling moment balances the normal righting moment for the angle of heel developed.
FORCES THAT CAUSE THE SHIP TO HEEL DURING TURNING
Example
Calculate the angle of heel developed when a ship doing 20 knots achieves a steady rate of turn to starboard and the radius of the turning circle is 300 m given that: KM = 8.00 m, KG = 6.00 m & KB = 2.5 m
Example
20 Knot = 20 * 1852 metres per hour /(60*60) =10.289 meter / second GM=KM-KG = 8.00- 6.00 = 2.00 m BG = KG - KBBG = 6.00 - 2.50 = 3.50 m
Tan θ = (10.2892 x 3.50) / 9.81 x 300 x 2.00 = 0.06295 angle of heel θ = 3.6 to Port
Example 2
Calculate the maximum speed on a turning circle of diameter 620 m in order that the heel developed does not exceed 6° given that: KM = 15.88 m KG = 14.26 m KB = 8.05 m maximum speed = 17.75 knots
INCREASE IN DRAUGHT DUE TO List / HEEL
Example
A ship heels 50 as it makes a turn. If the draught when upright is 7.60 m calculate the draught when heeled given that the breadth is 18 m.
Example
Draught when heeled = (0.5 x 18 x Sin 5 ) + (7.60 x Cos 5 )
