Part C | 31.1
690 Part C Coastal Design
drydocks and other repair-type vessels. Construction
equipment includes derricks, barges, tugs, dredges, and
various specialty craft.
While designed for different purposes and each
having unique characteristics, there are common dimensions and measurements between all vessel types
of which engineers and designers should be aware.
The most commonly used measurements for ships
assess both the physical dimensions of ships and the
amount of cargo that they can carry. For harbor or
port design, the principal dimensions of a ship include
length overall (LOA), length between perpendiculars
(LBP) beam (width), averaged draft, freeboard, molded
depth, longitudinal (broadside) wind area, and transverse (head-on) wind area. The beam is the measure
of the breadth of a ship at its widest point. LOA is the
measure of a distance from the bow of a ship to the
stern. The draft of a vessel is the vertical distance between the waterline and the deepest part of the ship at
any point along the length of the vessel. Other measurements of vessel which are important to the harbor/port
design include displacement (the displacement is the
weight of the water of the displaced volume of the ship),
DWT (deadweight tonnage, the total carrying capacity of the vessel including cargo, crew, water, fuel, etc.
DWT is typically the measurement used to place ships
into different classes but is not needed for design rather
used only for classification), center of gravity, center of
buoyancy, metacenter, and center of flotation. Important
coefficients of form of vessel include block coefficient
(the ratio of the immersed hull volume at a particular
draft to that of a rectangular prism of the same length,
breadth, and draft as the ship), midship section coefficient (the ratio of the area of the immersed midship
section at a particular draft to that of a rectangle of
the same draft and breadth as the ship), the waterplane
coefficient (the ratio of the area of the waterplane to
that of a rectangle of the same length and breadth as
the ship), and longitudinal prismatic coefficient (the ratio of the immersed volume to the volume of a prism
with length equal to the ship’s and cross-section area
identical to the midship section). For container ships,
vessels may also be classified by TEU (twenty-foot
equivalent unit) capacity. A TEU refers to the container
used to ship goods at sea which typical measure 20 ft
long by 8 ft high by 8 ft wide (1 TEU) or 40 ft long
by 8 ft high by 8 ft wide (2 TEUs). For mooring analysis, the layout of onboard mooring equipment will be
important. For berthing analysis, in addition to ship’s
mass and principal dimensions, hull radius is needed
which is sometimes difficult to obtain. For ship navigation studies, the vessel parameters (or key components)
that affect the vessel maneuverability will be required;
these parameters or components include vessel wind
coefficients, current coefficients, wave hydrodynamic
coefficients, engine type and power, rudder type specifications, bow/stern propellers, etc.
By using many of the measurements above, ships
can be placed into different classes. Classes vary by
the type of a ship, but most are broken up into DWT
ranges. Handi or Handymax vessels are traditionally the
backbone of the dry bulk vessels. Some classes are also
derived from trade route restrictions that limit where
certain sized ships can travel in the world. Canals, such
as the Panama and Suez, offer ships a more direct route
to destinations, but the lock systems used in these canals
limit the maximum size of vessels that can pass through.
The Panamax class is an example of a class that was
created due to size restrictions in the Panama Canal.
The name Panamax refers to the maximum size ship
that can fit through the locks in the Panama Canal.
Capesize vessels are too large for the Suez or Panama
canals and must travel around the capes of South Africa
or South America when making long voyages. Malacamax refers to the largest that can pass the Strait of
Malacca between Malaysia and Indonesia. While different types of cargo ships may share class names, the
ranges and limits of the defining measurements may
vary. Table 31.1 gives example ranges of some of the
different classes.
The world’s fleet of ships has changed greatly over
the past decades and will continue to do so in the future.
In 2011, the world cargo carrying fleet was comprised
of over 60 500 ships with a total gross tonnage of a trillion tons. It is predicted that as ships continue to get
bigger, a larger percentage of total fleet DWT will come
from a fewer number of ships. Ports worldwide are
looking at ways to accommodate larger ships, as the
size of new vessels keeps increasing. The Panama Canal
hopes to have its third set of locks operational by 2016,
which would allow post-Panamax ships to make use of
the canal. Figure 31.8 illustrates the increase in vessel
size that the Panama Canal expansion will allow it to
handle.
With a basic understanding of ship types and sizes,
it is easier to understand what must be considered when
working on a port-type project. Different types of cargo
ships have different characteristics and measurements
that must be taken into account to design the most effective marine environment.
31.1.3 Harbor Operational Limits
Operational limits can be divided into different levels,
from cargo handling limit based on maximum allowable
vessel movements at berth to the upper limit that a vessel can stay at berth, but with cargo handing ceased,
then to the ultimate limit that a vessel can stay at berth
690 Part C Coastal Design
drydocks and other repair-type vessels. Construction
equipment includes derricks, barges, tugs, dredges, and
various specialty craft.
While designed for different purposes and each
having unique characteristics, there are common dimensions and measurements between all vessel types
of which engineers and designers should be aware.
The most commonly used measurements for ships
assess both the physical dimensions of ships and the
amount of cargo that they can carry. For harbor or
port design, the principal dimensions of a ship include
length overall (LOA), length between perpendiculars
(LBP) beam (width), averaged draft, freeboard, molded
depth, longitudinal (broadside) wind area, and transverse (head-on) wind area. The beam is the measure
of the breadth of a ship at its widest point. LOA is the
measure of a distance from the bow of a ship to the
stern. The draft of a vessel is the vertical distance between the waterline and the deepest part of the ship at
any point along the length of the vessel. Other measurements of vessel which are important to the harbor/port
design include displacement (the displacement is the
weight of the water of the displaced volume of the ship),
DWT (deadweight tonnage, the total carrying capacity of the vessel including cargo, crew, water, fuel, etc.
DWT is typically the measurement used to place ships
into different classes but is not needed for design rather
used only for classification), center of gravity, center of
buoyancy, metacenter, and center of flotation. Important
coefficients of form of vessel include block coefficient
(the ratio of the immersed hull volume at a particular
draft to that of a rectangular prism of the same length,
breadth, and draft as the ship), midship section coefficient (the ratio of the area of the immersed midship
section at a particular draft to that of a rectangle of
the same draft and breadth as the ship), the waterplane
coefficient (the ratio of the area of the waterplane to
that of a rectangle of the same length and breadth as
the ship), and longitudinal prismatic coefficient (the ratio of the immersed volume to the volume of a prism
with length equal to the ship’s and cross-section area
identical to the midship section). For container ships,
vessels may also be classified by TEU (twenty-foot
equivalent unit) capacity. A TEU refers to the container
used to ship goods at sea which typical measure 20 ft
long by 8 ft high by 8 ft wide (1 TEU) or 40 ft long
by 8 ft high by 8 ft wide (2 TEUs). For mooring analysis, the layout of onboard mooring equipment will be
important. For berthing analysis, in addition to ship’s
mass and principal dimensions, hull radius is needed
which is sometimes difficult to obtain. For ship navigation studies, the vessel parameters (or key components)
that affect the vessel maneuverability will be required;
these parameters or components include vessel wind
coefficients, current coefficients, wave hydrodynamic
coefficients, engine type and power, rudder type specifications, bow/stern propellers, etc.
By using many of the measurements above, ships
can be placed into different classes. Classes vary by
the type of a ship, but most are broken up into DWT
ranges. Handi or Handymax vessels are traditionally the
backbone of the dry bulk vessels. Some classes are also
derived from trade route restrictions that limit where
certain sized ships can travel in the world. Canals, such
as the Panama and Suez, offer ships a more direct route
to destinations, but the lock systems used in these canals
limit the maximum size of vessels that can pass through.
The Panamax class is an example of a class that was
created due to size restrictions in the Panama Canal.
The name Panamax refers to the maximum size ship
that can fit through the locks in the Panama Canal.
Capesize vessels are too large for the Suez or Panama
canals and must travel around the capes of South Africa
or South America when making long voyages. Malacamax refers to the largest that can pass the Strait of
Malacca between Malaysia and Indonesia. While different types of cargo ships may share class names, the
ranges and limits of the defining measurements may
vary. Table 31.1 gives example ranges of some of the
different classes.
The world’s fleet of ships has changed greatly over
the past decades and will continue to do so in the future.
In 2011, the world cargo carrying fleet was comprised
of over 60 500 ships with a total gross tonnage of a trillion tons. It is predicted that as ships continue to get
bigger, a larger percentage of total fleet DWT will come
from a fewer number of ships. Ports worldwide are
looking at ways to accommodate larger ships, as the
size of new vessels keeps increasing. The Panama Canal
hopes to have its third set of locks operational by 2016,
which would allow post-Panamax ships to make use of
the canal. Figure 31.8 illustrates the increase in vessel
size that the Panama Canal expansion will allow it to
handle.
With a basic understanding of ship types and sizes,
it is easier to understand what must be considered when
working on a port-type project. Different types of cargo
ships have different characteristics and measurements
that must be taken into account to design the most effective marine environment.
31.1.3 Harbor Operational Limits
Operational limits can be divided into different levels,
from cargo handling limit based on maximum allowable
vessel movements at berth to the upper limit that a vessel can stay at berth, but with cargo handing ceased,
then to the ultimate limit that a vessel can stay at berth