Capitol University

Cagayan de Oro City

COLLEGE OF MARITIME EDUCATION
Bachelor of Science in Marine Transportation
SEA 001 (SHIPS, SHIP’S ROUTINES AND SHIPS CONSTRUCTION)

WEEK 1 & 2

Topics:
Principal Structural Parts of a Ship
a. Ship Dimension and Forms
b. Structural Members
c. Characteristics
d. Various Types of Ships
e. Functions of Different Bulkheads
f. Bow and Stern
g. Rudders, Thrusters, and Propellers
STCW
A-II/1. F3. C2 Maintain seaworthiness of the ship
Competence

KUP/s: A-II/1. F3. C2. KUP4. General knowledge of the principal

KUP
structural members of a ship and the proper names for the various parts

CO1: Differentiate the various parts and principal structural members of

Course Outcomes the ship in terms of their characteristics, functions, and contribution to
the maintenance of ship's seaworthiness.

LO1.1 Explain how the characteristics and functions of the parts and
Learning
structural members of the ship contribute to the maintenance of ship’s
Outcomes
seaworthiness

1. The learner reads the given materials and watches the

supplementary videos on the link provided.
2. Actively participates in the discussion and demonstrate
Learning Activities
knowledge on the importance of Navigational Astronomy and
Celestial Bodies Used in Navigation
3. The learner answers and pass the assessments given by the
instructor

INTRODUCTION

Principal Structural Parts of a Ship

A ship comprises both visible as well as invisible parts. E.g. rudder, anchor, bow, keel,
accommodation, propeller, mast, bridge, hatch coves and bow thrusters are some
common visible parts. In contrast, bulkheads, frames, cargo holds, hopper tank, double
bottom, girders, cofferdams, side shell etc., are the invisible parts of a ship.

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To understand parts of a ship, one must have to go through some common terms.

The most forward part of a ship is called a Bow; the left-hand side of the ship is referred
to as port, whereas the right side is called starboard. Likewise, the front side is termed as
forward and the backside as astern.

Monkey Island:

 Monkey Island is a sort of deck located at the topmost accessible height of the ship and
just above the bridge.
 This part of a ship is sometimes also referred to as a flying bridge and, in the past, was
used by the sailors for solar and stellar observations. In addition, it houses a magnetic
compass.
 It is an integral part of ship and houses driving units such as VDR capsule, AIS Tx/Rx
antennae, Radar scanner(s) attached to the radar mast, Sat C/F77 Tx/Rx antennae,
communication equipment gear, various halyards connected to the yardarm to hoist
flags, weather vane, and the masts leading up to the ‘Christmas Tree’ (navigation lights)
and the ship’s aft whistle.

Bridge:

 The ship’s bridge is the commanding station of a ship. It controls the ship movement
through its navigational equipment.
 It controls important deck machinery, main engine and ship’s navigation system.
 Functions that are usually performed on the ship bridge are: controls the ship’s speed
and direction (navigation), monitor weather and sea conditions, navigating and fixing the
position of the ship, and facilitating internal as well as external communication.

Funnel:

 A Funnel or Stacks is a chimney on a vessel used to discharge engine and boiler smoke.
 Lifting of the exhaust gasses, clear from the deck, is the constitutional purpose of the
Funnel.

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Accommodation:

 The accommodation area is the house for crews and lives. It has all the amenities,
including offices, gym, crew cabins, hospital, salon, recreation room, common rooms,
laundry, and galley.
 It is a key part of the ship and consists of the garbage disposal system, freshwater
system, sewage treatment plant, refrigeration system (domestic) and air conditioning for
the accommodation block.
 It is a necessary part of a ship and facilitates space for relaxing, medical facility and food
courts.

Funnel Deck:

 The funnel releases exhaust gases into the atmosphere from the engine exhaust room
of the ship. It has a similar function to chimneys in factories.
 Nowadays, extra care has been taken in discharging shoot from the funnel to preserve
the atmosphere from pollution.
 These funnels are never installed straight but inclined at a certain angle toward the aft so
that the flue gases will not cause hindrance to the deck and navigation bridge.

Boat Deck:

 The deck floor covers the ship hull structure. There can be multiple decks or deck
sections on a ship. The deck at the top, which bears maximum exposure to weather, is
the main deck or weather deck.
 Based on the position of a ship’s deck, decks are of six main types; main deck, poop
deck, upper deck, lowers deck, weather deck and foredeck.
 The boat deck’s main function is holding the hull structure and providing the floor to work
and standing and guard them against outside weather.

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Mast:

 The mast is a rangy spar arrangement that is elevated more or less vertically to the
Centreline of a ship.
 It has several purposes, including carrying derricks and giving fundamental height to the
navigation light, salient yards, radio or radar aerials, and scanners.

Flying Bridge:

 It is an extended area on top of a weather deck or an open area of the superstructure,

which provides an unobstructed view of the fwd and aft along with the vessel’s sides to
the navigational officers.
 It also serves as an operating station for the officer and crew of the watch.
 It also contains a duplicate set of controls, which is vital for the master, ship’s officers,
and pilot for berthing and unberthing the vessel.

Stem:

 The front-most part of the boat or ship’s bow is termed as the Stem of the ship.
 The keel itself is extended up to gunwale to form the curved edge called the ship’s stem.

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  These stems can be of two styles viz. raked and plumb stems, where the former is
inclined at some angle to the waterline and later is perpendicular to the waterline.

Forecastle:

 The forecastle is one of the foremost parts of the ship of length less than 7% of the total
deck length.
 It was initially used in military vessels, in which the soldiers used forecastles to take
defensive positions.
 But, today, forecastle serves many functions such as holding, anchoring and securing
the major parts of the ship.

Foredeck:

 The foredeck is the forward part of a weather deck, between the superstructure and the
foc’sle superstructure.
 Basically, it is a part of the vessel forward of the mast.

Bulbous Bow:

 It is a jut out bulb at the bow of the vessel just below the W/L.
 It cuts the water and tweaks the water flow around the hull, increasing the vessel’s
speed, fuel efficiency and stability.
 12-15% of better fuel efficiency is observed in the vessel with the bulbous bow.
 It also increases the buoyancy of the onward part of the vessel, which reduces pitching
up to some extent.

Stern:

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  The stern is an aft-end structure designed to provide low resistance, high propulsion
efficiency, and avoid vibrations.
 It is the rearmost part of a ship that keeps the water out. Rudders and propellers are
hanged to the stern.
 The stern can be shaped flat, canoe-like, tapered, sharp to serve the purpose of cutting
the water in its way.

Poop Deck:

 It serves as a roof to the cabin constructed in the aft of the ship.

 It facilitates the captain and helmsman to supervise the entire working crew.
 But in modern ships, the poop decks are provided either in the centre of the ship or on
the starboard.

Side Thrusters:

 These are somewhat like a propeller and fitted on either side of the bow of the ship.
 It helps in manoeuvring ships at a slow speed in congested waters near ports or canals.
These are also referred to as tunnel thrusters.
 Side thrusters influence the total running cost of a ship to a greater extent. These are
either hydraulically or electrically powered.

Rudder:

 Without steering, we can’t move a vehicle in the desired direction, so the propeller
propels the ship, and the rudder steers the ship. The rudder is a flat hollow structure
housed in the aft of the propeller.
 It consists of the following parts: rudder trunk, moveable flap, main rudder blade, hinge
system, links and rudder carrier bearing. Rudders are of three types: balanced type,
semi-balanced type and unbalanced type rudder.
 As a vital part of the ship, the rudder is provided with a steering gear system that
controls the rudder’s movement. It works on Newton’s Third Law of motion.

Propeller:

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  It is a mechanical device having blades fitted on a central shaft. These blades rotate,
and their rotational energy is converted into pressure energy, and due to this,
the propeller produces the thrust required for propulsion. It pushes the seawater
backwards, and, in turn, the seawater helps the ship move forward.
 Engine, shaft and propeller together constitute propulsion unit. The propeller should be
made up of aluminium, bronze, manganese etc., which are excellent corrosion resistant
alloys. There can be one, two or three propellers.
 It is the most important part of the ship without which a ship can’t move. So, the main
function of the propeller is to propel the ship in the forward direction by producing thrust
on water. Its working principles are Newton’s third law of motion and Bernoulli’s theorem.

Paint Room:

 A small onboard area is required in marine vessels to handle and store paint. This room
is known as the Paint room.
 Special provisions are there for the paint room to cater explosions and release of
chemical gases and vapours from these enamels.
 There should be explosion-proof lighting in the paint room, and brackets should be
available to provide flexible mounting and storage of paints.

Emergency Generator Room:

 When the main supply goes out of order, a small separate generator supplies electricity
for emergency loads. This is called an emergency generator.
 It is located above the topmost deck, away from main and secondary machinery and
collision bulkhead, and has its own switchboard in its surroundings.
 This generator should be easily operable and can be started at even 0°C

Ballast Tanks:

 The compartments maintained specially to carry water, which serves the purpose
of ballasting and stabilizing the vessel, are termed Ballast Tanks.
 These tanks should be provided with proper care to prevent corrosion, as seawater is
highly corrosive.
 These tanks are revolutionary to the marine industry as, before their evolution, solid
ballast was used, and their discharge is quite difficult compared to easier pumping of
liquid ballast.

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Bunker tanks:

 The tanks on the ships used to store fuel and lube oils on ships are known as bunker
tanks.
 These lube oils are required for safer machinery operations, and the fuel is used for
emergency or regular operations.
 As these tanks store sludge, diesel, oils etc., which can catch fire immediately, they are
provided separately and far from ignition prone areas.

Duct Keel:

 A duct keel is a hollow structure that consists of two longitudinal girder and solid plates
and is welded to form a box-type structure, which is generally provided in double-hull
ships.
 The duct keel should provide a watertight passage along the ship length. It consists of a
sounding pipe for leakage detection.
 This is a multi-functioning part of the ship for performing several functions like provide
resistance to loads, carry water pipelines, ballast pipelines, oil pipes, etc.

Ship Cargo gear (Derrick/Cranes etc.):

 Derricks (Cranes) are used to lift and carry the safe working load on a ship.
 These are electrically or hydraulically operated equipment for easier operations.
 The capacity of ship cargo cranes and gears for handling cargos is 15 tons to 4000 tons
per hour.

Samson Post/King Post:

 It is a heavy vertical post that supports the cargo booms.

 It rests on the Keelson and supports the deck beam of a vessel.

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Cargo hold:

 Enclosed spaces to retain and store cargo or freight containers carrying coal, grain and
salt are referred to as cargo holds.
 The cargo hold is located under the ship’s deck and has a holding capacity ranging from
20 tons to 200000 tons.
 The main function of the cargo hold is to preserve cargo when it is transported to the
destination.

Hatch Cover:

 To prevent the cargo storage from spoilage, especially to make storage spaces airtight
and watertight, hatch covers are required. Generally, to save the food items ( or any
other cargo) transported by ship from rain during the voyage.
 The design of the hatch cover changes according to the type of the vessel, but the only
requirement is that it should be quick enough to provide faster cargo handling
processes.
 In the past, these hatch covers were crane or winch driven, but today, mainly
hydraulically driven hatch covers are used.

Freeboard:

 Freeboard can be defined as the distance measured from the waterline to the higher
edge of the freeboard plating/deck plating at the sides of amidships.
 The classification society must approve the minimum freeboard calculation for a vessel.
 The calculation of freeboard plays a critical role in defining the load line marks of the
vessel, which in turn, is directly related to the cargo-carrying or the earning capacity of
the vessel.

Hull:

 The hull is a watertight vessel’s body that may be open or partially covered with a deck.
 Hull has several watertight decks and bulkheads as the major transverse membrane.

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  The intermediate member of the hull consists of girders, webs and stringers.
 Depending on the structural arrangements, there may be longitudinal members for
strengthening purposes.

Deck House:

 It is a house-like structure on the upper deck.

The ship, an important trading source through seaways, may be made up of different styles and
sizes. Some parts are called essential parts, common to all ships, but others are just
accessories to provide luxurious or improved shipping.

All the parts which form the ship should be checked for proper working, and precautions should
be taken for risky equipment.

Three necessary parts of the ship are the hull (the main body of the vessel), navigation bridge
(helps in directing the ship in the proper direction) and engine room (propels ship or helps in
moving). However, today modern ships are equipped with the most modern equipment and
technologies to their different parts to improve voyages at sea.

a. Ship Dimension and Forms

Principal Dimensions
The shapes shown in a lines plan delineate what is called the molded form of the vessel. The
principal dimensions of a ship are length between perpendiculars, beam, draft, and depth.
These quantities are shown in Figure 5 and are defined as:

 Length Between Perpendiculars (LBP or L): The horizontal distance between the forward
and aft perpendiculars is called the length between perpendiculars. It is constant for a
given ship and does not depend on the loading condition of the ship.
 Beam (B): The breadth of the ship at the broadest point is called the beam.
 Draft (T): The vertical distance between the waterline and the deepest part of the ship at
any point along the length is the draft. Drafts are usually measured at the forward, Tf,
and the aft, Ta, perpendiculars although they can also be defined at the fore and aft draft
marks which may not coincide with the perpendiculars. The mean draft, Tm, is the
average of the forward and aft drafts.

Other Measurements
In addition to the principal dimensions, the following, also shown in Figure 5, are also used in
describing ships:

 Length Overall (LOA): The extreme length of the ship along the centerline is called the
length overall.
 Length on Waterline (LWL): This is the length along the centerline at the waterline in the
ship's design loaded condition.
 Freeboard (F): This is the distance between the waterline and the uppermost watertight
deck at any location along the ship.

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  Displacement Volume (V): The displacement volume is the total volume of the
underwater hull at any given waterline.
 Displacement (W): The displacement is the weight of the water of the displaced volume
of the ship; for static equilibrium it is the same as the weight of the ship and all cargo on
board. Therefore, displacement is directly related to displacement volume and it can be
found by multiplying the volume with the specific gravity of the water in any set of
consistent units. For example if the volume is in cubic feet, we may divide it by 35 to get
the displacement in long tons in seawater, or by 36 in fresh water.
 Buoyancy: Any ship partially or wholly imersed in water will experience an upward push
called buoyancy. The force of buoyancy is equal to the weight of the volume of water the
ship displaces.
 Reserve Buoyancy: The watertight volume between the waterline and the uppermost
continuous watertight deck is the reserve buoyancy of the ship. It enables the ship to
take on additional weight, and it is closely related to the ability of the ship to survive a
damage.
 Moment of Inertia (I): For hydrostatic calculations we will always refer to the moment of
inertia as the second moment of area unless specified otherwise. It is a measurement of
a plane surface's resistance to rotation about an axis in the same plane. The magnitude
of the moment of inertia depends upon the shape of the area and the location and
orientation of the axis of rotation. The moment of inertia is measured in the fourth power
of a linear unit, such as ft4, in4, or a combination.
 Tonnage: Tonnage is a description of the cargo capacity of a merchant ship. It is a
volume measurement and does not directly indicate displacement
 Sheer: The difference between the design trim freeboard at any point and that of the
midship section. The sheer line is the line of intersection of the main or weather deck
with the side of the ship.
 Camber: This represents the curvature in an athwartship or transverse vertical plane; it
is the height of the deck at the centerline above the height at the side.
 Tumble Home: The slant inward from the vertical of a transverse section of a hull above
the design waterline. Tumble home is the opposite of flare.
 Flare: the slant upward and outward from the vertical of a transverse section of a hull
above the design waterline.
 Deadrise: The athwartship rise of the bottom from the keel to the bilge.

Flotation Characteristics
The following terms are used with regards to ship flotation:

 Trim: Trim is the difference between the drafts forward and aft. Typicallu, we assign
positive and negative values to trim to indicate trim (down) by the stern or trim (down) by
the bow respectively.
 List, Heel, and Roll: Angular transverse inclinations of ships are described as list, heel,
or roll, depending on the nature of the situation. List describes a definite attitude of
transverse inclination of a static nature. Heel describes a temporary inclination generally
involving motion, while roll indicates periodic inclination from side to side. For example, a
ship rolls in a seaway, lists due to a side damage, and heels in a turn.

b. Structural Members
A ship structure is complex webwork of various items and entities made up of different steel
breeds, all of which have their importance. Let us look into some essential terms associated
with ship construction or crucial aspects of the vessel’s structure.

Scantlings

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Before discussing the various tenets of the ship’s structure, it is essential to know about scantlings. The term
refers to the dimensions and sizes of the various structural members. Scantling is a direct determinant of the
strength of the particular member and resilience against loads.

Calculating it is a crucial part of basic design and precedes any detailed plan. The importance of scantling
calculations derives from section modulus, an indicator of the member’s resistance to loads based on the size,
form, type, and make of any structural member.
The higher the section modulus of the member, the higher the strength and hence, the ability to withstand
higher degree loads.

For all practical purposes, scantling calculations are of two types: Local and Global Scantling Calculations.
Global scantling calculation alludes to the determination of hull strength structure as a whole, considering all
larger members. Determination of the scantlings and resultant section modulus using the midship section of a
vessel is a very commonly used method of determining global scantlings.

On the other hand, local scantling alludes to determining the strength or load-resisting capabilities of individual
sections under consideration. Suppose we have a structural panel comprising plating and a network of
transverse and longitudinal members. The overall load resisting ability of the panel can be estimated by local
scantling calculations from the individual thicknesses of the members, material properties, dimensions,
orientation, and overall arrangement.

Keel
This is perhaps the most critical structural member of any vessel compared to the backbone or the foundation
of any building. Keel is the bottommost structural member of the ship and runs longitudinally unstinted from
forward to aft.

All load paths from the structural members in the hull are directed towards the keel, which absorbs a
considerable load. Besides these, the keel must also withstand many external loads from the environment
when the vessel is underway. Usually, laying the keel is the first step in the construction process of most
ships.

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The keel should be aligned with the vessel’s centreline. It has the highest degree of scantlings or dimensions
for apparent reasons.
Keels are primarily of three types: i) Flat Plate, ii) Bar Keel, iii) Duct Keel. A flat plate keel is the most common
among the three.

Platings
The hull structure comprises joined plates whose thickness depends on vessel type and size. As expected,
larger ships have heavier scantlings of plates, and smaller vessels have lower values. The plating thickness
also depends on the location.

The plating thickness at the bottom and sides is higher than the deck plating. Generally, for all practical
purposes, the thickness of the steel plates for smaller vessels (<100 m) is within the range of 10-15 mm,
whereas for larger ships (>100 mm), it is greater than 10mm.

Now, the plates available for shipbuilding are of various forms. They may be flat or bend depending on the
requirement. For example, plates used at deck and side shells are primarily straight, whereas those at the
corner locations like bilge areas are bent.
In a broad sense, the plates used are classified as bottom shells, side shells, and deck platings. The types of
steel depend on the structural areas and the thicknesses. The most common types of plates used are steel
grades A, B, D, or E, including sub-categories.

Strakes
Strakes are plates in the side and bottom structure. The A strake or the Garboard strake are the plates on
either side immediately adjacent to the keel. The immediate plates on either side are referred to as strakes B,
C, D, and so on. The strake plates at the bottom corners or the turn of the bilge are known as the bilge
strakes. Similarly, the outer uppermost side vertical plating at the deck edge is known as sheer strakes.

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Single and Double Hull
Vessels have either single or double hulls, like most tankers. The double hull has an external plating system
followed by an internal plating system parallel to the outer shell. This is primarily to enhance the strength of
the hull and offer protection for structural damages. The spaces between the two hulls on the sides may store
ballast, fuel, or bilge water. The inner and outer shells of plating are joined by interspersing structural
members.

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Single Bottom and Double Bottom Structure
Like single and double hull, a vessel can be a single bottom, for smaller ships, or double bottom, for larger
vessels. For double bottoms, an inner shell plating is present at a certain height above the lowermost bottom
shell for bolstering strength and protection against flooding. Now, all double hull structures are double-bottom
as well, as obvious. However, all double-bottom vessels are not double-hull and may be single-hull at all other
places!

Bulkheads
Bulkheads are vertical partitions or walls arranged either longitudinally or transversely. The arrangement of
bulkheads in longitudinal and transverse directions divides the hull into separate compartments, holds, tanks,
or spaces.

The bulkheads may be watertight or oil-tight or may have openings. The main watertight bulkheads are crucial
for creating watertight compartments or spaces helpful in maintaining water tightness while dealing with the
stability issues of the vessel during flooding. Classification rules decide the number and disposition of the
bulkheads based on the size and type of vessel.

The bulkheads also act as strength members for absorbing loads and preventing structural effects, especially
transverse ones. The bulkheads are fabricated based on requirements and are often strengthened by vertical
and horizontal support members.

Pillars and Stanchions

Pillars and stanchions are vertical support members that act as joiners between two successive decks to
transfer loads from the upper to the lower deck and subsequently to the bottom structures.

Stiffeners
All plates in the hull structure need to be strengthened in various ways to increase their load-absorbing
capabilities. For the same reason, stiffening members of multiple types are placed in all directions (transverse
and longitudinal). These strength members are standard rolled steel sections or simply plates and bars,
depending on the requirement.

Longitudinals
Longitudinals are stiffeners that run in a longitudinal direction, i.e., from forward to aft. They resist the
longitudinal loads and their effects like bending stresses and buckling and support other connected members.
They have definite scantlings and are uniformly spaced depending on the vessel’s bottom and the decks.
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Stringers
The longitudinals placed at the vessel’s side shell platings are called stringers. For double hull configurations,
stringers are both for the inner and outer shell.

Girders
Girders are heavy scantling longitudinal stiffeners situated at the bottom, sides, and deck, with greater
dimensions than longitudinal. Large bars, I-beams, or high scantling L-sections are placed at definite intervals
between longitudinals in the top and bottom structure. The keel is often a girder of high dimensions.

Frames
The transverse structural members run from the keel to the deck edge at the main deck level. They are
usually perpendicular to the outer shell plating and transversely stiffen the outer side shell and outer bottom
plating.

Floors
They are a part of the frames in the bottom structure, ideally from the keel to the bilge strake level. Floors
have higher scantlings than the part of the frame on the side shells. They usually stiffen the bottom shell
plating against lateral loads and, for double bottom constructions, also help support the inner bottom plating.
Floors are generally of two types, solid floors and bracket floors.

Deck Beams
They are transverse stiffening members running laterally and strengthening the deck plating.

Brackets
They are supporting members usually between a vertical and horizontal structural member that not only
absorbs forces but also creates a continuous load path between members.

Transverse and Longitudinal Framing

For shorter vessels, there are more transverse members like frames than longitudinals, which are
comparatively closely spaced. This is due to the effects of lateral loading, and this system is known as
transverse framing. Longer vessels are more susceptible to flexural or longitudinal loading effects, and hence
they have closely spaced longitudinal members greater than transverse, and this system is known as
longitudinal framing.
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Hatches are nothing but covers on openings at various deck levels for the access of men, cargo, or other
items. These are also stiffened and of a specific strength to compensate for the loss of strength on deck
structures due to the openings or cut-outs. They may be watertight or non-watertight.

Bulwarks are high projections from the side shell plating or walls above the main deck level for additional
protection. They may be of low scantling but do not contribute much to the vessel strength.

c. Characteristics

What are the characteristics of cargo ships?

Cargo ships are usually specially designed for the task, often being equipped with cranes and other
mechanisms to load and unload, and come in all sizes. Today, they are almost always built of
welded steel, and with some exceptions generally have a life expectancy of 25 to 30 years before
being scrappe.

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Various Types of Ships

Various Types of Ships

Types of Ships
Following are the main types of ships that are travel worldwide:

Bulk carrier ships

Bulk carriers are merchant ships transporting dry cargo, such as grain, coal, ore, steel coils, cement, etc., in
bulk quantities. The first special bulk carriers were built in 1852. Bulk carriers are known for their maximum
capacity, safety, efficiency, and durability.

Despite this, cargo loading operations can vary, and loading and unloading cargo can take several days. Bulk
carriers may be gearless, rely on terminal equipment, or sometimes fitted with a crane integral to the ship.
Nowadays, bulk carriers make up 21% of the world’s merchant fleet and are available in sizes from single-
hold mini-bulk carriers to giant ore ships.

Advantages
These are intended to transport large amounts of dry bulk cargo such as coal, iron ore, grains, and other
commodities.
Bulk carriers are available in various sizes and designs, allowing for flexibility in accommodating cargo types
and navigating various waterways and port facilities.
Disadvantages
Shipping in bulk can be more expensive than shipping in containers.
Compared to goods stacked on top of one another, overweight or oversized cargo takes up more room on a
freighter.

Container ships

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Container ship
A container ship is a cargo ship that carries all of its load in truck-size intermodal containers, in a technique called
containerization. Container ships are a common means of commercial intermodal freight transport and now carry
most seagoing non-bulk cargo. A container ship (also called boxship or spelled containership) is a cargo ship that
carries all of its load in truck-size intermodal containers, in a technique called containerization. Container ships are
a common means of commercial intermodal freight transport and now carry most seagoing non-bulk cargo.

Container ship capacity is measured in twenty-foot equivalent units (TEU). Typical loads are a mix of 20-foot (1-
TEU) and 40-foot (2-TEU) ISO-standard containers, with the latter predominant.

Today, about 90% of non-bulk cargo worldwide is transported by container ships, and the largest modern container
ships can carry up to 24,000 TEU
Dredgers

The primary function of a dredger is to remove deposited sediments such as sand, silt, or gravel from inlet
streams, waterways, or the ocean floor. Simply put, these are ships containing excavation equipment that are
used to remove sand and other types of deposits from the ocean floor.

These ships are used for many purposes, such as navigating shallow coastal areas, deep-sea mining, etc.
Common types of dredgers include simple jet-lift and air-lift, auger suction, pneumatic and amphibious
dredgers.

Advantages
Dredgers are essential for maintaining and constructing waterways, including ports, channels, and harbors.
These are employed in projects aimed at reclaiming land from the seabed.
Disadvantages
Dredging operations can disturb or displace marine organisms, altering their behavior, migration patterns, and
breeding cycles.
In water bodies, dredging can change the equilibrium between erosion and sedimentation.

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Fishing vessels

Fishing vessel is used for fishing at sea or on a lake or river. A fishing vessel uses a conical net that traps fish
by dragging it through or down the water. There are many different types that are used in commercial, artistic,
and recreational fishing.

The total number of fishing vessels worldwide in 2016 was approximately 4.6 million. It is difficult to estimate
as they range in size from small dinghies to large charter cruisers and, unlike commercial fishing vessels, are
often not dedicated solely to fishing. Fishing vessels are mainly classified into two types which are trawlers
and non-traveling vessels.

Advantages
These vessels can reach areas with large fish populations, allowing for efficient harvesting of marine
resources.
Due to their contribution to the global seafood supply, fishing vessels are crucial in ensuring food security.
Disadvantages
It is common for fishing vessels to catch endangered or protected species unintentionally, known as bycatch.
Typically, fossil fuels are used to power fishing vessels, which results in fuel consumption and the emission of
greenhouse gases and air pollutants.

Gas carriers

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A gas carrier, also known as an LPG, or LNG carrier, is a vessel designed to transport LPG, LNG, CNG, or
liquefied chemical gases in bulk. They are built to move liquefied gases at low-temperature pressure between
terminals equipped with fully refrigerated storage tanks. Their great feature is the presence of round tanks
above the main deck.
LNG gas carriers differ markedly in that they have large circular tanks on their deck. They are available in 4
different types of tanks: independent tank, membrane tank, integral tank, and semi-membrane tank. On the
other hand, chemical cargo ships have multiple tanks to protect them from mixing the different substances
they carry.
Advantages
Liquid gases can be efficiently transported over long distances thanks to gas carriers.
LNG has lower carbon emissions than conventional fossil fuels like coal or oil, so gas carriers support the
transportation of these cleaner energy sources.
Disadvantages
Gas carriers move highly flammable and potentially dangerous gases like liquefied natural gas (LNG) and
liquefied petroleum gas (LPG).
For loading and unloading operations, gas carriers require specialized infrastructure and facilities.

High-speed craft
High-speed craft uses air pressure to move at high speed over water and has engines and turbine propellers
to move them. These ships were trendy when they were launched and still maintain their popularity.

These types of ships are advanced, high-performance (usually high-speed) marine vessels designed for
civilian use, also known as fast yachts. Most of these technologies are not used in commercial ships. Mainly
high-speed crafts serve as passenger ferries.

Advantages
The efficiency of transporting people and goods can be increased by using high-speed craft, which can reach
speeds that are significantly faster than those of conventional vessels.
Even at high speeds, high-speed craft are built to provide a smooth and comfortable ride.
Disadvantages
Compared to conventional vessels, high-speed craft are typically more expensive to construct, maintain, and
operate.
Compared to slower ships, the high-speed craft uses more fuel per unit of distance travel.

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Naval ships
It is a military ship used by the Navy. Naval ships are large, heavily armed surface ships primarily
designed to engage enemy forces on the high seas, including battleships, destroyers, and corvettes.

These are differentiated from civilian ships by construction and purpose. These ships are damage resistant
and equipped with weapon systems, although the armament on military transport is light or non-existent. They
were designed primarily for naval warfare and are called warships.

Advantages
Naval vessels protect a country’s maritime assets by offering security and protection from potential dangers.
Naval ships are frequently used for humanitarian assistance and disaster relief.
Disadvantages
Naval ships, which tend to be extremely advanced warships, can be costly to construct, run, and maintain.
These are exposed to modern weapons systems, such as submarines, torpedoes, and anti-ship missiles.

Offshore
ships are mainly used for oil exploration and construction at sea. There are many types of offshore vessels. In
addition, these ships provide transit and respite to crew personnel to and from the operational areas of the
high seas when required.

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As noted above, the term offshore vessels is a collective context and include a wide range of vessels
employed in the region of the high seas. These ships are usually 50 to 100 meters (160 to 330 ft) in length
and perform various tasks such as logistic support and transportation of goods, equipment, and equipment.

Advantages
To support offshore operations in the oil and gas sector, offshore ships like supply ships and platform support
ships are essential.
These have equipment and safety features to protect the well-being of the staff and deal with emergencies.
Disadvantages
For safe and effective operations, offshore ships rely heavily on weather conditions.
These ships are complex vessels with modern technology and equipment. Their operation and maintenance
necessitate skilled personnel and specialized training.ffshore ships

Passenger ships
Passenger ships are also known as cruise ships, primarily for transferring passengers from one place to
another. Unlike the seaplanes used for transportation, cruise ships are usually used for round-trip voyages to
various ports, where passengers can go on tours.

Modern types of passenger ships have less hull strength, speed, and agility than seagoing ships. Although
they have added facilities to cater to water tourists, recent ships have been described as “floating
condominiums laden with balconies.” Generally, cruise ships do two to three nights or more round trips
without visiting any port.

Advantages
Passenger ships offer a unique and enjoyable travel experience, allowing passengers to visit different
locations and participate in leisure activities.
They make a significant economic contribution to the cruise industry by promoting local business growth,
creating jobs, and bringing in tourism revenue.
Disadvantages
Ships that carry passengers, especially large cruise ships, can have a substantial environmental impact.
Passenger ships may become overcrowded, especially during busy travel times, resulting in clogged common
areas, lengthy lines, and insufficient personal space.

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Roll-on Roll-Off ships
Roll-on roll-off ships are types of ships that are used to carry wheeled cargo. Wheeled cargo is nothing other
than cars, motorcycles, trucks, buses, and railroad cars are driven on and off a ship, either on their wheels or
using a platform vehicle, such as Self-propelled modular transporter.

Roll-on roll-off ships contrast with lift-on/lift-off (LOLO) ships, which use cranes to load and unload cargo.
RORO ships have built-in or shore-based ramps or ferry slips that allow cargo to be rolled on and off the
vessel efficiently. The word RORO is generally used for large ocean-going vessels.

Advantages
Ro-Ro ships provide effective cargo handling capabilities, enabling the direct driving of vehicles, machinery,
and other wheeled cargo onto and off the vessel.
Cars, trucks, trailers, construction equipment, and even perishable goods can all be transported on ro-ro
ships.
Disadvantages
Although Ro-Ro ships can transport various wheeled cargo, they might not be able to transport all non-
wheeled cargo.
Ro-Ro ships need specialized port facilities with proper ramp systems and enough room for vehicle loading
and unloading.

Livestock carriers
A livestock carrier is a large vessel used for the live animal export of sheep, cattle, and goats. These types of
ships are typically newly built or converted from container ships. When transporting livestock, adequate
ventilation, food, and water are primary considerations.

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Livestock carriers must carry enough food for the animals during the journey and enough stock for
emergencies. Common livestock carriers have a capacity of about 30,000 to 40,000 sheep (or 3000 to 4000
head of cattle). Livestock carriers typically travel the Middle East between Australia and New Zealand.
Advantages
Livestock carriers are specifically designed to transport live animals safely and decently.
Livestock carriers support the export and import of livestock between nations by facilitating the trade of live
animals internationally.
Disadvantages
The risk of disease transmission and outbreaks can rise when animals are kept in close quarters in livestock
carriers.
It can be difficult for livestock carriers to comply with local, state, and federal laws about environmental
standards, biosecurity, and animal welfare.

Heavy life ships

As the name suggests, a heavy-duty ship is designed to carry heavy industrial components that regular ships
cannot handle. They are huge ships capable of carrying other ships, large industrial units, floating plants, etc.

For example, these ships transport offshore platforms from construction to drilling sites. Some are equipped
with high-capacity cranes for loading at ports without bulky capacity. And some allow the cargo to float in
position before the ship lifts the cargo out of the water.

Advantages
Large and heavy loads that cannot be carried by standard cargo ships can only be transported by heavy lift
ships.
Heavy lift ships transport heavy cargo to remote or inaccessible locations worldwide.
Disadvantages
Because of their specialised design and equipment, heavy lift ships have a limited cargo capacity.
To load and unload heavy cargo, heavy lift ships need the appropriate port facilities and machinery.

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Tanker ships
Tanker ships are designed to transport large amounts of stored liquids or gases. Tanker ships are further
classified into different types based on their cargo. The main types include oil tankers, chemical tankers, and
gas carriers.

Apart from their applications, these ships also carry commodities such as vegetable oil, molasses, and
alcohol. In the United States Navy, a tanker used to refuel other ships is called an oiler. Tankers can range in
size from several hundred tons in capacity for long-distance transportation.

Advantages
Tanker ships are made for the safe transportation of liquid cargo, including liquefied natural gas (LNG),
chemicals, crude oil, and petroleum products.
Because tanker ships can transport large amounts of cargo, they can benefit from economies of scale.
Disadvantages
Safety is the top priority because tanker ships transport hazardous and flammable materials.
Tanker ships are extremely dependent on fluctuations in the oil industry.

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Tugs
A tug is a marine vessel that operates other ships by pushing or pulling along a direct contact or tow line.
These boats usually haul vessels that cannot sail well independently, such as in crowded harbors or narrow
canals.
Modern tugs are highly maneuverable, with pulling power that can exceed 100 tons. Early tug models had
steam engines, while modern ones had diesel engines. Some tugs are sea-going, and some are icebreakers
or rescue tugs. Many tugs carry deluge guns, aiding firefighting, especially in harbors.
Advantages
Tugboats are designed and outfitted with powerful engines and towing equipment to help tow and move larger
vessels such as ships, barges, or floating structures.
Tugboats give ships more propulsion and control, improving maritime operations safety.
Disadvantages
Tugboats typically travel at slower speeds than other types of vessels, which limits their usefulness for lengthy
journeys or operations that must be completed quickly.
Tugboats depend on outside variables like weather, water depth, and tidal patterns.

Canoe
A canoe is a light vessel, usually pointed at both ends and opened from above. These are typically driven by
one or more seated or kneeling paddlers facing the direction of travel and using single-blade paddles.
Currently, canoes are widely used for competition and pleasure, such as racing, whitewater, touring and
camping, freestyle, and general entertainment. Most modern canoes are molded plastics or composites such
as fiberglass or Kevlar or incorporate graphite. The intended use of canoes is determined by their size, length,
and construction material.
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Advantages
Canoes are highly maneuverable watercraft that allows easy navigation in various water bodies, including
rivers, lakes, and calm coastal areas.
On the water, canoes offer a quiet and environmentally friendly mode of transportation.
Disadvantages
Compared to larger watercraft, canoes have a smaller carrying capacity.
Canoes are less stable than other types of watercraft, particularly in rough conditions or when loaded
unevenly.

Yacht
A yacht is a sailing or power vessel used for pleasure, cruising, or racing. These types of ships have a cabin
with facilities that are suitable for overnight use. The vessel is expected to be at least 33 feet (10 m) in length
and may be judged to have good aesthetic qualities
These are powered by electrical power provided by a motor-driven alternator or a battery recharged by the
motor. There are mainly two types of yachts available; Racing yachts are designed to emphasize performance
over comfort, and charter boats are run as a for-profit business.
Advantages
For individuals or groups, yachts offer a private and exclusive environment.
Yachts can be modified and customized to fit particular preferences and requirements.
Disadvantages
The smooth sailing, guest services, and onboard maintenance often require a crew when operating a yacht.
A yacht comes with several upfront costs, including the purchase price, maintenance, crew salaries,
insurance, fuel, and docking fees.

A hovercraft

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is a floating craft capable of traveling over land, water, mud, ice, and other surfaces. A hovercraft has a skirt to
contain air. When the air blower is turned on, this skirt creates a pocket that traps pressurized air. That
pressurized air gives a hovercraft lift to move forward.

Nowadays, they are used worldwide for disaster relief, Coast Guard, military, survey applications, and
specialized transport for sport or passenger service. As the hovercraft rises above the surface, there is no
friction between the skirt and the ground, so it can travel smoothly on the land.

Advantages
Hovercraft can travel across various surfaces, including ice, mud, marshes, and water.
Hovercraft can travel at high speeds, often faster than traditional boats or vehicles.
Disadvantages
Because of the operation of their engines and fans, hovercraft make a lot of noise.
Compared to other forms of transportation, hovercraft typically have a lower capacity for passengers and
cargo.

Submarine
submarine, also known as a sub, is a vessel capable of independent operation underwater. This differs from a
submersible, which has limited capability underwater. Submarines usually have large ballast tanks filled with
air that help them float on the ocean’s surface.
At the top of the ballast tank are valves that are opened when the submarine is timed to submerge. Most large
submarines have a cylindrical body with conical ends, usually located in the middle, which houses
communication and sensing equipment and periscopes. Submarines include a wide range of types and
capabilities.
Advantages
With their ability to operate underwater while submerged, submarines can be hidden and operate stealthily.
In naval combat, submarines provide an offensive and strategic advantage.
Disadvantages
They are less useful in situations that call for fast pursuits or agile movements because they are slower and
less flexible than surface vessels.
Due to their complexity and advanced technology, submarines have high construction and maintenance costs.

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Sailboat
is a boat partly or wholly propelled by sails and smaller than a sailing ship. The forces of the wind on the sail
and the water on the underwater parts of the boat combine to propel the boat through the water.
When the wind blows across the sails, the aerodynamic lift is created, much like the wing of an airplane.
Some sailboats have motor propellers, which help propel the sailboat even with no wind.
Advantages
Sailboats are energy and environmentally friendly due to their reliance on wind energy for propulsion.
On the water, sailing offers a calm and peaceful experience.
Disadvantages
Sailboat propulsion heavily depends on wind conditions. Their speed and maneuverability may be restricted
by calm or unstable winds.
When there is bad weather, like a storm or strong winds, sailboats may have trouble.

Barge
A barge is a flat-bottomed boat that runs on a river and can transport bulk cargo. The barge can be self-
propelled, usually with a slow-rotating diesel engine and a large-diameter fixed-pitch propeller.

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Draft horses initially pulled the barges on an adjacent towpath. Some other types of barges must be pulled by
tugs or pushed by pusher boats. Compared to towed barges, the pusher system has improved handling and is
more efficient, as the pushing tug becomes part of the unit, contributing to the movement of the whole.
Advantages
Barges are able to move a lot of cargo on a single trip thanks to their large cargo carrying capacity.
Since they can travel through inland waterways like rivers, canals, and lakes, they can access places that
other modes of transportation might not be able to.
Disadvantages
Compared to other forms of transportation like trucks or trains, barges typically travel at a slower speed.
Docks, ports, and waterways with navigable channels are necessary for barges to operate efficiently.

Corvette ship
A corvette is a type of small warship. It is generally the smallest class of ships regarded as official warships. In
the modern era, a corvette can be used as a fast attack craft, missile boat, and coastal patrol craft.
Typically, these corvettes weigh between 500 and 2,000 tonnes. Recent corvette designs may weigh up to
3,000 tonnes and have a hangar to house a helicopter, making them similar in size and functionality to smaller
frigates.

Reefer vessel
A reefer ship is a refrigerated cargo ship designed for transporting perishable cargo, such as fruits, meat,
vegetables, dairy products, and similar items that require temperature control.

Simply put, a reefer ship can carry the equivalent of 40 to 250 trucks, depending on its size. Due to the
extensive trade between the hemispheres, reefer ships operate seasonally but can operate all year long.

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Frigate
A frigate is a kind of naval warship that is bigger and more heavily armed than a corvette while also being
smaller and faster than a destroyer. Frigates can hold a crew of several hundred sailors and are typically
between 110 and 150 meters long.

In order to engage enemy targets, these ships frequently have a combination of surface-to-air missiles, anti-
ship missiles, torpedoes, and naval guns. In naval operations, frigates are essential for convoy protection,
maritime surveillance, maritime interdiction, and supporting larger fleet operations.

Panamax ship
A ship that meets the maximum construction requirements to pass through the Panama Canal is referred to
as a panamax ship. The word “Panamax” is a combination of the words “Panama” and “maximum.”
These vessels are made to fit through the locks and narrow channels of the Panama Canal, a vital
international shipping route that connects the Atlantic and Pacific Oceans.
Normally, Panamax ships can carry between 65,000 and 80,000 deadweight tonnes (DWT) of cargo. Some
Panamax ships can transport many shipping containers and are also equipped to handle containerized cargo.

d. Functions of Different Bulkheads

Bulkheads
Bulkheads in ships are similar to internal walls dividing a building into separate rooms. Vertical partitions
arranged either transversely or longitudinally in ships are known as transverse bulkheads and longitudinal
bulkheads respectively-
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Functions of bulkheads
1. Bulkheads divide the main hull into different compartments and in the event of a damage to the shell
plating bulkheads limit the extend of flooding and hence of loss of buoyancy.
2. Bulkheads also prevent spread of fire from one compartment to another.
3. Transverse bulkhead prevents racking and torsional distortion on a ship.
4. Longitudinal bulkheads contribute to the longitudinal strength of the ship.
5. Bulkheads divide the main hull of a ship into different compartments such as the aft peak tank, engine
room, cargo holds, deep tanks, cofferdam space, and the fore peak tank.
Bulkheads are either watertight or non-watertight although such terms as oil tight and gas tight bulkheads have
been used.
Transverse watertight bulkheads divide the main hull into many different watertight compartments.
Watertight bulkheads are attached to the shell, the deck, and the bottom or tank top by welding
Non watertight bulkheads are any other types of bulkhead which are non water tight such as centreline wash
bulkhead in the peak tanks, partial bulkheads in the accommodation spaces, stores and cargo holds.

The number of transverse bulkheads in a ship is dependent on the length of the ship. However all ships must
have the following bulkheads-
 a collision or fore peak tank bulkhead
 an aft peak tank bulkhead
 a bulkhead at each end of the engine room

e. Bow and Stern

The bow (/baʊ/) is the forward part of the hull of a ship or boat,[1] the point that is usually most forward when
the vessel is underway. The aft end of the boat is the stern.
Prow may be used as a synonym for bow or it may mean the forward-most part of the bow above the
waterline.
Many types of bows exist. These include:

Straight-stem bow plumb bow raked bow

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flared bow clipper bow or "Aberdeen bow" Bulbous bow

Inverted bow Ram bow High-chin spoon bow

Low-chin spoon bow

Common Types of Ship’s Sterns

The sterns can be broadly classified into the following –

Elliptical Stern
Cruiser Stern
Transom Stern
Elliptical Stern
Merchant stern or elliptical stern or counter stern was the conventional form for cargo ships during the early
20th century. If viewed from above, the deck line and the knuckle line are roughly elliptical. Counter stern or
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cutaway sterns are characterized by an upwardly curved profile, beginning fore of the aft perpendicular. They
are similar to cruiser stern. However, on the counter, the cutaway for the rudder occurs above the waterline,
and consequentially the counter stern has a pronounced aft overhang and exposed skeg. Benefits of having a
counter stern include larger deck space in the aft, a measurable amount of reserve buoyancy provided, and
an aesthetic choice for the owner.
Cruiser Stern
The cruiser stern was initially designed only to lower the steering gear below the armour deck. A cruiser stern
is characterized by an upward curved profile from the after perpendicular to the main deck or poop. Unlike the
counter stern, a cruiser stern cutaway for the rudder occurs below the waterline (the rudder is fully submerged
at the design waterline). The cruiser has better resistance characteristics than the merchant stern. The length
of the waterplane with a cruiser stern is greater than Lpp. A cruiser stern presents a more pleasing profile and
is hydrodynamically efficient.
Transom Stern
A transom stern is a stern shape characterized by a generally flat shape extending to the waterline. The
transom stern offers a greater deck area aft, is a simpler construction, and can also provide improved flow
around the stern. The flat surface of any transom stern may begin either at or above the vessel’s waterline. A
transom stern can be viewed as a cruiser stern whose aft-most portion is cut off.

f. Rudders, Thrusters, and Propellers

Rudders,

Rudders are hydrofoils which are pivoting on a vertical axis. They are located normally at the stern behind
propeller(s) to produce a transverse force and steering moment about the ship centre of gravity by deflecting
the water flow to the direction of the foil plane.

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Thrusters,
transversal propulsion devices built into, or mounted to, either the bow or stern, of a ship or boat to make it
more manoeuvrable. Bow thrusters make docking easier, since they allow the captain to turn the vessel to
port or starboard side, without using the main propulsion mechanism which requires some forward motion for
turning;

Propellers
A propeller is a rotating fan-like structure that is used to propel the ship by using the power generated and
transmitted by the main engine of the ship.

Supplementary Videos to Enhance Learning

Principal Structural Parts of a Ship https://www.youtube.com/watch?v=IMo90U02Aa0

https://www.youtube.com/watch?v=KUMTAoJDXNc

Assessment Tasks

Formative Assessment 1.1:

At the end of the learning activities, the student should be able to answer the Prelim Quiz no.
1(on week 2) multiple choice questions about the characteristics and functions of the parts and
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structural members of the ship contribute to the maintenance of ship’s seaworthiness

References

https://www.marineinsight.com/guidelines/parts-of-a-ship/

https://www.marineinsight.com/guidelines/parts-of-a-ship/
https://www.theengineerspost.com/types-of-ships/
https://nauticalchannel.com/new/proa-y-popa

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