[5] ptk 2014 2015 ship main particulars

Course-5 Introduction to Marine Technology
Ships Main Particulars
Lecturer : Adi Wirawan Husodo, ST, MT
© Adi Wirawan Husodo
2014
Odd Semester 2014/2015
1

References
• Dokkum, K.V., 2003, Ship Knowledge: A Modern Encyclopedia,
Dokmar, Netherland.
2014
2

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.
2014
3

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.
2014
4

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.
2014
5

2014
6
http://4.bp.blogspot.com/-_mjvnVV-L6U/
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0/final+loadline+mark.jpg
http://s0.geograph.org.uk/geophotos/02/98/90/2989045
_d8fa1bb3.jpg

2014
7

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.
2014
8

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.
2014
9

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.
2014
10
• 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.

2014
11

Volumes and Weights
• Register Ton
• Register ton is actually a measure of the volume of enclosed spaces
on 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).
2014
12

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.
2014
13

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
2014
14

Volumes and Weights
2014
15

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)
2014
16

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;
2014
17

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)
2014
18

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)
2014
19

Midship coefficient (Cm or )
• Ratio of the area of the midship section (Am) and the area
bounded by Bmld and T
2014
20

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”.
2014
21

Block coefficient (Cb or )
2014
22

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.
2014
23

2014
Thank You
24

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