Ports Terminals workability

Prof. Ing. Paolo De Girolamo

Lecture index

• Basic concepts of ports• Basic concepts of port terminals • Mean annual capacity of a terminal• Berth occupancy factor• Optimum terminal capacity• Random arrival of the ships• A compromise between antithetical objectives• Introduction and description of the final exercise of this course

Portus from latin «door»

A protected area of calm water for easy transfer of goods and passengers

A system of activities and services to support navigation and connectmaritime transport to land transport

PORTS definitions

PORTS definitions 1. General cargo terminal2. Container terminal3. Passenger terminal4. Fuel dock5. Fishing harbour6. Shipyard7. Waiting quay for ship repair8. Anchorage area9. Turning circle10. Mooring buoys11. Breakwaters12. Tug pier13. Coastline

Area where ships moor waiting

for entry into the port

Waiting area

Port terminals

Terminal functions

Port terminals are those port facilities that constitute the factual interface between different modes of transport of the cargo.

In commercial ports, the terminals are the 'raison d'etre' (reason for being) of a port.

All other facilities are provided only to enable the terminals to function, and that in a safe and efficient manner.

Port terminals are the node or link of connection of the intermodal transport chain.

Ports are the most complex nodes of intermodal transport network.

Transport modes

The transport modes are:

1. Maritime transport (sea);2. Inland water transport (fluvial);3. Road transport (land);4. Rail transport (land);5. Transport by pipelines;6. Air transport (Plane).

In a port up to 5 transport modes may converge and/or diverge.

In general a Port is the interface between the sea and the land transports (by roads or by rail).

The services provided by a terminal are:

• Loading (import) or unloading (export) of goods from ship to shore, or the reciprocal process;

• Temporary storage of goods;

• Sometimes a limiting processing of the goods;

• The loading or unloading into or from the through-transport means.

Services provided by a terminal

The (un)loading of the ship is carried out in some cases by ship-born gear (e.g. liquid bulk-cargoes, some dry bulk-cargoes and multi-purpose vessels).

Specialized terminals generally uses shore-based equipment (e.g. containers terminals).

Portainers for containers loading/unloading

Types of Port Terminals The main types of terminals that can be distinguished are:

• Conventional general cargo terminals• Multi-purpose terminals• Ro-Ro terminals• Container terminals• Liquid bulk terminals, such as for import and export of:

- liquid gas- crude oil- oil products- edible oil- wine- chemical products

• Dry bulk terminals, such as for,- cereals- ore and coal- special products (cement, sulphur, etc.)

• Fruit terminals• Fish handling facilities• Inland Water Transport Terminals• Ferry terminals• Marinas

An example of a container terminal

The containers loading/unloading on the quay

Storage area for the temporary storage of containers

Containers handling from the quay to the storage area and vice versa

Containers handling in the storage areaContainers handling of the outgoing / incoming containers by roads

Basic concepts of a maritime terminals

(1) Loading or unloading of the ship(2) Land connection by roads and railway(3) Storage area for the temporary storage of the goods

(1) (2)(3)

Scheme of a port terminal

Basic concepts of a maritime terminals

(1) Loading or unloading of the ship(2) Land connection by roads and railway(3) Storage area for the temporary storage of the goods

(1) (2)(3)

Scheme of a port terminal

The goods storage area has the function of a buffer, or, using an hydraulics comparison, of a water reservoir in the water supply system of a town. Storage of goods is also required for customs and security reasons.

The “buffer” has the function of separating the arrival and departure times of the containers inside the terminal, from the operations of loading and unloading the ships.

The capacity of the goods storage area has to compensate the differences between:a) the rate of loading and unloading of the ships andb) the rate of through-transport (road and or rail).

Note that a>>b.

Mean annual capacity of a terminal

The mean annual capacity of a terminal expresses the quantity of goods that can be handled on average in one year by the terminal.

For example, for a container terminal it is expressed by the number of TEUs averagely handled in one year.

Mean annual capacity of a terminal

The mean annual capacity of a terminal depends on:

The berths occupancy factor

The berths occupancy factor

The berths occupancy factor, generally evaluated as an average annual value, expresses the relationship between the occupation time of the berths with respect to the total available time.

For example, considering a terminal made by only one berth, if the berth occupancy factor is equal to 0.5 it occurs that, on average during one year, a ship performing loading / unloading operations is present at the berth only 50% of the available time (6 months). The maximum theoretical value of the berth occupancy factor is 1.

It is impossible to obtain a berth occupancy factor equal to 1 because:- there are at least some "physiological" times during which the ship cannot load or

unload, as for example the time necessary to the ship to enter and exit from the port. - in addition there are a number of factors, mainly of stochastic nature, which may

influence the loading and unloading times of ships.

We can state that:

A high berths occupancy factor causes an increase in the waiting time of the ships.

The ship’s waiting time is a problem for the shipping companies because during the waiting time the ships do not operate but the shipping company has to bear the relative costs.

The berths occupancy factor

• Optimum annual capacity.

The optimum annual terminal capacity is the sort of capacity with which the port planner has to deal.

‘Optimum’ can be defined in different ways.

Optimum for a shipping companyFor a shipping company the optimum coincides with the minimum waiting time of their vessels.

Optimum for a terminal operatorFor a terminal operator (owner of the terminal) the optimum is to achieve the highest level of the berths occupancy factor, as this increases the mean annual capacity of the terminal and therefore his earnings.

Optimum terminal capacity

Random arrival of the ships

In general we can state that:

If we assume a random time arrival of the ships, the berth occupancy factor is a statistical parameter

and that:

- a random arrival of the ships and a low acceptable waiting time of ships lead to a low value of berths occupancy factor;

The random time arrival of the ships is normally expressed as the number of ships arriving during one week (i.e., 5 ships/week)

A compromise between antithetical objectives

➢ The goal of the terminal operator (owner of the terminal) is to achieve the highest level of the berths occupancy factor, as this increases the mean annual capacity of the terminal and therefore his earnings;

In conclusion we can state that:

➢ The goal of the shipping companies is to guarantee to their ships a minimum waiting time.

These two objectives are clearly antithetical to each other.

The optimum may be obtained by guaranteeing the greatest possible berths occupancy factor in compliance with an acceptable maximum waiting time of the ships.

A compromise between antithetical objectives

In order to resolve these antithetical objectives, a contract is stipulated between the terminal operator and the shipping companies.

The contract establishes an acceptable maximum waiting time for vessels. This waiting time is called laytime (in italian “tempo di stallia“).

The laytime could be described, for example, by a guarantee that:

- no more than x% of the vessels visiting the terminal, will have a waiting time in excess of y hours and/or

- that no more than m% of the vessels will have a total port time in excess of n hours.

The waiting time which exceeds the laytime is called "demurrage time“ (in Italian tempo di controstallia”). The demurrage (assessed economically), when it occurs, is paid by the port operator to the shipping company.

This criterion can be used as a basis for optimizing the terminal

A compromise between antithetical objectives

The tools used in quantifying these optima, are discrete simulation models.

The application of a discrete simulation model yield , for specific boundary conditions, the ship waiting times.

This study may be a part of the cost minimization study.

In conclusion, the optimization of a terminal can be carried out by defining the maximum berths occupancy factor which respect a maximum waiting time of the ships.

For a container ship it is often assumed that the maximum waiting time of the vessel in the port from when she arrives to when she leaves is about 24 hours.

Introduction and description of the final exercise of this course

The goal of the final exercise of this course that you will do with Prof. Alessandro Romano is:

The development and application of a discrete simulation model in order to optimizethe berths occupancy factor a container terminal.

Analysis of the problem and process schematization

Optimization of the berths occupancy factor a

container terminal by means of a discrete

simulation model

waiting area

Ships operations to access the quays to perform loading and unloading operations

Let's consider a terminal that consists of a single ship place.

We analyze the ships operations to access the quays in order to perform loading and unloading operations

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

2. If the quay is occupied by another ship, the ship must wait for the quays to be freed outside the port in the waiting area. The time the ship waits outside the port is called the vessel's waiting time.

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

2. If the quay is occupied by another ship, the ship must wait for the quays to be freed outside the port in the waiting area. The time the ship waits outside the port is called the vessel's waiting time.

3. When the quay is freed, the command to enter the port is given to the ship.

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

2. If the quay is occupied by another ship, the ship must wait for the quays to be freed outside the port in the waiting area. The time the ship waits outside the port is called the vessel's waiting time.

3. When the quay is freed, the command to enter the port is given to the ship.4. Then the ship leaves the mooring outside the port and with the help of the tugs

enters the port and moors.

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

2. If the quay is occupied by another ship, the ship must wait for the quays to be freed outside the port in the waiting area. The time the ship waits outside the port is called the vessel's waiting time.

3. When the quay is freed, the command to enter the port is given to the ship.4. Then the ship leaves the mooring outside the port and with the help of the tugs

enters the port and moors.5. Once the ship is moored, the ship's hatches are opened and loading and unloading

begins.

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

2. If the quay is occupied by another ship, the ship must wait for the quays to be freed outside the port in the waiting area. The time the ship waits outside the port is called the vessel's waiting time.

3. When the quay is freed, the command to enter the port is given to the ship.4. Then the ship leaves the mooring outside the port and with the help of the tugs

enters the port and moors.5. Once the ship is moored, the ship's hatches are opened and loading and unloading

begins.6. The duration of the loading and unloading operations depends on:- the number of containers to be unloaded and loaded from the ship; - the weather conditions. Excessive wind or excessive wave motion can cause the

vessel motion and therefore may slow down loading and unloading operations;- the number of work shift per day (1, 2 or 3);- whether or not the holiday are respected;- the probability of occurrence of strikes;- the probability that the cranes could break. Most of these variables may be treated as a random variable making the problem very complex.

Ships operations to access the quays to perform loading and unloading operations

1. The ship arriving the port, asks permission to enter the port in order to reach the quay where the unloading and loading operations will be performed;

2. If the quay is occupied by another ship, the ship must wait for the quays to be freed outside the port in the waiting area. The time the ship waits outside the port is called the vessel's waiting time.

3. When the quay is freed, the command to enter the port is given to the ship.4. Then the ship leaves the mooring outside the port and with the help of the tugs

enters the port and moors.5. Once the ship is moored, the ship's hatches are opened and loading and unloading

begins.6. The duration of the loading and unloading operations depends on:- the number of containers to be unloaded and loaded from the ship; - the weather conditions. Excessive wind or excessive wave motion can cause the

vessel motion and therefore may slow down loading and unloading operations;- the number of work shift per day (1, 2 or 3);- whether or not the holiday are respected;- the probability of occurrence of strikes;- the probability that the cranes could break. Most of these variables may be treated as a random variable making the problem very complex.7. When the ship completes the unloading and loading operations, the ship's hatches are closed, the ship is unmoored and she is towed by the tugs outside the port.

Ships operations to access the quays to perform loading and unloading operations

In order to simplify the problem we assume:

- the total duration of the loading and unloading operations of each ship is constant and it is equal to 24 h.This duration includes all the dead times necessary for the ship to enter and exit the port, to open and close the ship's hatches , etc.

The only random variable which we consider is the number of ships which arrives to the port every week.

λ = number of ships arrivalsin a week (random variable)

λ

Of (%) = berth occupancy factorOf

The real time simulator will have to provide the following results:

λ = number of ships arrivalsin a week (random variable)

λ

Of (%) = berth occupancy factorOf

The real time simulator will have to provide the following results:

Wt (hours)= ship waiting time

λ

Wt

λ = number of ships arrivalsin a week (random variable)

λ

Of (%) = berth occupancy factorOf

The real time simulator will have to provide the following results:

Wt (hours)= ship waiting time

λ

Wt

Wt max

λopt

Wt max

Of opt

λ opt is the value of λ which provides the maximum acceptable ship waiting time Wt max.

At λ op, the optimal value of the berth occupancy factor Of opt is also obtained