The document defines key ship dimensions and terms used to describe a ship's size and structure. It explains measurements like length overall, length between perpendiculars, beam, draft, depth, and definitions of areas like the bow, stern, port, and starboard. It also summarizes tonnage measurements including displacement tonnage, lightweight tonnage, deadweight tonnage, gross tonnage, and net tonnage. Load line markings and their purpose are briefly described as well.

1. Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.
SHIP CONSTRUCTION-
SHIP DIMENSIONS

2. Definitions and
Ship’S DimenSionS
Hull:
The structural body of a ship including shell plating, framing, decks
and bulkheads.
Afterbody :
That portion of a ship’s hull abaft midships.
Forebody:
That portion of a ship’s hull forward midships.
Bow :
The forward of the ship
Stern :
The after end of the ship
8/23/2014 2
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

3. Length Overall
STARBOARD
Beam
PORT
bow midships bridge stern
8/23/2014 3
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

4. starboard bow
starboard beam
starboard quarter
Dead ahead Dead Stern
Port bow
Port beam
port quarter
8/23/2014 4
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

5. Port :
The left side of the ship when looking forward
Starboard :
The right side of the ship when looking forward
8/23/2014 5
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

6. Length between perpendicular (LBP)
Length on waterline (LWL)
Length overall (LOA)
freeboard
Amidships
Aft
perpendicular
Fwd
perpendicular
Sheer aft Sheer fwd
Summer load line
SHIP DIMENSIONS
Camber
Tumble home
Depth
Moulded beam
Rise of
floor Half siding of keel
Base line
Draft
8/23/2014 6
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

7. • After Perpendicular (A.P.): A perpendicular
drawn to the waterline at the point where the aft
side of the rudder post meets the summer load
line. Where no rudder post is fitted it is taken as
the centre line of the rudder stock.
• Forward Perpendicular (F.P.): A perpendicular
drawn to the waterline at the point where the
foreside of the stem meets the summer load line.
• Length Between Perpendicular (L.P.P. / L.B.P.):
The length between the forward and the aft
perpendiculars measured along the summer load
line.
8/23/2014 7
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

8. • Amidships: A point midway between the after
and forward perpendiculars
• Length Overall (L.O.A.): Length of the vessel
taken over all extremities.
• Base line: A horizontal line drawn at the top of
the keel plate. All vertical moulded dimensions
are measured relative to this line
• Moulded beam: Measured at the midship
section is the maximum moulded breadth of the
ship
8/23/2014 8
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

9. • Moulded Draft/ Draught: The distance from
the bottom of the keel to the waterline. The
load draft is the maximum draft to which a
vessel may be loaded
• Moulded Depth: Measured from the base line
to the heel of the upper deck beam at the
ship’s side a idships.
• Sheer: Curvature of decks in the longitudinal
direction. Measured as the height of deck at
side at any point above the height of deck at
side amidships
8/23/2014 9
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

10. • Camber / Round of Beam: Curvature of decks
in the transverse direction. Measured as the
height of deck above the height of deck at
side
• Rise of floor / Deadrise: The rise of the
bottom shell plating line above the base line.
This rise is measured at the line of moulded
beam
• Half sliding of keel: The horizontal flat portion
of the bottom shell measured to port or
sta oa d of the ship’s lo gitudi al e t e
line. This is useful dimension to know when
dry-docking.
8/23/2014 10
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

11. • Tumble home: The inward curvature of
the side shell above the summer load line.
• Freeboard: the vertical distance measured
from the waterline to the top of the deck
plating at the side of the deck amidships.
Normally exposed to weather and sea.
• Flare: The outward curvature of the side
shell above the waterline. It promotes
dryness and is therefore associated with
the fore end of ship
8/23/2014 11
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

12. Extreme Beam:
The maximum beam taken over all extremities.
Extreme Draft:
Taken from the lowest point of keel to the summer load line.
Draft marks represent extreme drafts.
Extreme Depth:
Depth of essel at ship’s side f o uppe de k to lo est poi t
of keel.
Half Breadth:
Si e a ship’s hull is sy et i al a out the lo gitudi al
centre line, often only the half beam or half breadth at any
section is given.
8/23/2014 12
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

13. SCANTLING
The dimensions of the structural items
of a ship, e.g. frames, girders, plating , etc.
INTERCOSTAL
Composed of separate parts, non-
continuous
8/23/2014 13
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

14. CENTER OF FLOATATION
It is the center of the waterplane area and is the
axis about which a ship changes trim.
CENTER OF BUOYANCY
It is the center of the underwater volume of the
ship where the force of buoyancy acts.
CENTER OF GRAVITY
It is the point at which the whole weight of the
object may be regarded as acting. If the object is
suspended from this point, it will remain balanced and
not tilt.
8/23/2014 14
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

15. TONNAGE MEASUREMENT
• This is often referred to when the size of
the vessel is discussed, and the gross
to age is uoted f o Lloyd’s egiste .
• Tonnage is a measure of the enclosed
internal volume of the vessel, 100 cubic
feet representing one ton
• Its normally divided into categories as
follow:-
8/23/2014 15
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

16. 1. Displacement Tonnage
• A ship’s displa e e t is the su of the ship’s
a tual eight light eight a d it’s o te ts
(deadweight).
• The metric unit of measurement is 1 tonne (=
1000 Kg).
• The displacement represents the amount of
water displaced by the ship expressed in tonnes.
• The weight of water displaced therefore equals
the weight of the ship
8/23/2014 16
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

17. TONNE PER CENTIMETRE (TPC)
It is the mass required to increase the mean draught by 1
centimetre.
LOAD DISPLACEMENT
The weight of the ship and its content, measured in
tonne. The value will vary according to the ship’s draught.
DEADWEIGHT SCALE
It is a scale diagram indicating the deadweight of the ship
at various draughts.
FORM COEFFICIENT
It is devised to show the relationship between the form of
the ship and the dimension of the ship.
8/23/2014 17
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

18. 2. Lightweight Tonnage (LWT)
• The lightweight is the weight of the ship as
built (hull, machinery) including boiler water,
lubricating oil and the cooling water system.
• Lightweight like displacement is expressed in
units of tones.
• It assumes importance in a commercial sense
only when considering the value of the vessel
which is to be broken up for scrape.
8/23/2014 18
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

19. 3. Deadweight tonnage (DWT)
• Deadweight is the weight of the cargo
which a ship carries plus weights of fuel,
stores, water ballast, fresh water, crew
and passengers and baggage.
• It is the difference between the loaded
ship displacement and the lightweight.
8/23/2014 19
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

20. 4. Gross Tonnage (GT)
• Measurement of total internal volume of
a vessel and includes all under deck
tonnage and all enclosed spaces above
tonnage deck.
• 100 cubic feet of space being considered
as 1 ton
8/23/2014 20
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

21. 5. Nett Tonnage (NT)
• Ship measurement derived from gross
tonnage by deducting spaces allowed for crew
and propelling power.
• 100 cubic feet of space being reckoned as 1
ton
8/23/2014 21
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

22. Ship side markings
• LOAD LINE
The marking on the ship side that relate to the loading
condition of the ship termed as the load line mark.
• Load line mark
– consists of a ring 300 mm in outside diameter and 25
mm thick which is
– intersected by a horizontal line 450 mm in length and 25
mm thick, the upper edge of which passes
through the centre of the ring. The centre of the ring is
placed amidships and at a distance equal to the
assigned summer freeboard measured vertically below
the upper edge of the deck line.
8/23/2014 22
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

23. 8/23/2014 23
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

24. 8/23/2014 24
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

25. Sailing ship
8/23/2014 25
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.

26. ANY QUESTION?
THANK YOU!
8/23/2014
Mohd. Hanif Dewan, Chief Engineer and
Maritime Lecturer & Trainer, Bangladesh.
26