[5] ptk 2014 2015 ship main particulars

© Adi Wirawan Husodo2014

Course-5 Introduction to Marine Technology

Ships Main ParticularsLecturer : Adi Wirawan Husodo, ST, MT

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References

• Dokkum, K.V., 2003, Ship Knowledge: A Modern Encyclopedia, Dokmar, Netherland.

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Definitions

• Length overall : Length of the ship over its extremities.

• Length between perpendiculars : Length from aft perpendicular (center of rudderstock) to forward perpendicular.

• Load line length : Length as used in freeboard calculation.

• Beam : Width of the hull, usually inside shell plating.

• Depth : Height from baseline to uppermost continuous deck at side, inside of plating.

• Draught : The maximal depth underwater, incl. shell plating.

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Definitions (2)

• Perpendiculars : Imaginary lines, perpendicular to the base line or plane (and the water line).

• Forward perpendicular (Fpp or Fp): this line crosses the intersection of the water line and the front of the stem.

• Aft perpendicular (App or Ap): This line usually aligns with the center line of the rudder stock (the imaginary line around which the rudder rotates).

• The perpendiculars are used when the lines plan is made. They are the ends of “block” where the underwater part of the hull fits in.

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Definitions (3)

• Load line : The water line of a ship lying in the water.

• Deck line : Extended line from the upper side of freeboard deck (or deck covering) at the ship’s side.

• Moulded dimensions : Distance between two points, measured at inside of shell plating (or outside framing).

• Base line : Top of the flat keel plate.

• Plimsoll mark or Freeboard mark : is a symbol indicating the maximum immersion of the ship in the water, leaving a minimal freeboard for safety.• Circle with a diameter of one foot (0.3048 m), through which a

horizontal line is drawn with is upper edge going through the center of circle.

• This level (horizontal line) indicates the minimum freeboard in salat water summer condition.

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http://4.bp.blogspot.com/-_mjvnVV-L6U/UTo0waNGvrI/AAAAAAAAC8Y/zKVb7mtXuTk/s160

0/final+loadline+mark.jpg

http://s0.geograph.org.uk/geophotos/02/98/90/2989045_d8fa1bb3.jpg


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Dimensions

• Length between perpendiculars (Lpp or Lbp) : distance between the Fore and the Aft Perpendicular.

• Length overall (Loa) : the horizontal distance over the extremities, from stem to stern.

• Length on the water line (Lwl) : horizontal distance between the points where bow and stern are going through water plane, at summer mark, less the shell plating (moulded).

• Draught Forward (Tfwd of Tf) : vertical distance between the water line and the underside of the keel, as measured at the forward perpendicular.

• Draught at the stern or Draught After (Ta or Taft) : vertical distance between the water line and the underside of the keel, as measured at the aft or after perpendicular.

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Dimensions (2)

• Trim : the difference between the draught at the stern and the draught at the stem.

• Trimmed by the head : draught forward is larger than at the stern.

• Trimmed by the stern : draught aft is larger than at the forward.

• On even keel (in proper trim) : the both draughts are equal.

• Breadth or beam (Bmld) : the greatest moulded breadth, measured from side to side at the outside of frames, but inside the shell plating.

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Dimensions (3)

• Freeboard : distance between the water line and the top of deck at the side (deck line).

• Summer Freeboard : the distance from the top of the Summer Load Line or the Plimsoll Mark and the upper edge of the deck line.

• Air draught : the vertical distance between the water line and the highest point of the ship.

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• Breadth overall : The maximum breadth of the ship as measured from the outer hull on starboard to the outer hull on port side, including rubbing bar, permanent fenders, etc.


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Volumes and Weights

• Register Ton

• Register ton is actually a measure of the volume of enclosed spaceson a ship (not vessel’s mass or weight).

• It used to determine the size of a ship.

• It is based on volume; 1 register ton = 100 cft or 2.83 m3.

• It is an internationally recognized basis for raising taxes from the shipping industry and setting levels of fees for port dues, towage, pilotage and canal passages.

• It is also used as a size determiner in both national and international shipping regulation. For example: ships of 1,600 GRT or more must have more comprehensive radio equipment than smaller vessel.

• GRT (Gross Register Tonnage), NRT (Net Register Tonnage).

• IMO in 1969 issued the new measurement system (Universal Tonnage Measurement System – UMS); GT (Gross Tonnage) and NT (Net Tonnage).

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Volumes and Weights

• Gross Register Tonnage

• Gross Tonnage

• Includes all enclosed spaces (volume below main deck and enclosed spaces above main deck).

• Net Register Tonnage

• Net Tonnage

• Just enclosed cargo spaces

• NT is derived from the GT by subtracting the volume of space occupied by : crew, navigation equipment, the propulsion equipment (partly), workshops, ballast.

• NT may not less than 30% of the GT.

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Volumes and Weights

• Gross Register Tonnage

• Gross Tonnage

• Includes all enclosed spaces (volume below main deck and enclosed spaces above main deck).

• Net Register Tonnage

• Net Tonnage

• Just enclosed cargo spaces

• NT is derived from the GT by subtracting the volume of space occupied by : crew, navigation equipment, the propulsion equipment (partly), workshops, ballast.

• NT may not less than 30% of the GT.

• All measurements in moulded dimensions

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Volumes and Weights

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Volumes and Weights

• Underwater volume or Carene (m3)• Moulded volume of a ship minus the contribution of the shell,

propeller and rudder.

• Displacement (m3) - • Also familiar with the term of Volume of Displacement

• Is the volume of the part of the ship below the water line including the shell plating, propeller and rudder.

• Is the volume of water displaced by the immersed body of ship (including the shell plating, propeller and rudder)

• Displacement (ton) - • Is the weight of the volume of water displaced by the ship.

• Equal to the total mass of the ship.

Displacement (ton) = volume of displacement (m3) x density of water (ton/m3)

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Volumes and Weights

• Lightship weight (ton) - LWT

• The weight of ship including the regular inventory, but without any cargo, fuel or crew.

• Regular inventory such as anchors, life saving appliance, LO, paint, etc.

• Deadweight (ton) – DWT

• This is the weight that ship can load until the maximum allowable immersion (summer load line).

• Or is the ship’s loaded capacity, including bunkers and other supplies necessary for the ship’s propulsion

• Is a fixed value;

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Form Coefficients

• Define the characteristics of the vessel’s shape below the design waterline.

• Non-dimensional figures.

• Volume based and area based.

• Area based:

• Water plane coefficient (Cw or )

• Midship coefficient (Cm or )

• Volume based:

• Block coefficient or coefficient of fineness (Cb or )

• Prismatic coefficient (Cp or )

• Vertival prismatic coefficient (Cpv)

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Water plane coefficient (Cw or )

• Ratio of the area of water plane (Aw) and the rectangular plane bounded by Lpp and breadth moulded (Bmld).

• A large water plane coefficient in combination with a small block coefficient is favourable for stability (transversal and longitudinal)

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Midship coefficient (Cm or )

• Ratio of the area of the midship section (Am) and the area bounded by Bmld and T

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Block coefficient (Cb or )

• or coefficient of fineness

• Ratio of the volume of the underwater body () and the rectangular block bounded by Lpp, Bmld and T.

• A small block coefficient vessel is referred to as “FINE”. 201

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Block coefficient (Cb or )

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Prismatic coefficient (Cp or )

• The ration of the volume of the underwater body and the block formed by the area of Midhsip Section (Am) and Lpp.

• Cp is important for the resistance and hence for the necessary power of propulsion.

• The smaller Cp, the smaller propulsion power.

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Thank You

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Engineering

[5] ptk 2014 2015 ship main particulars