ANALYSIS OF TIME-WINDOWS ON SHIP ARRIVAL AND ITS INFLUENCE ON
PORT OPERATIONS PERFORMANCE

Rui C. Botter*, Laherce R. Castro Neto**, Wellington R. A. Ceciliano**

*Naval and Ocean Engineering Dept
University of São Paulo
Av. Prof. Mello Morais, 2231, Cidade Universitária, São Paulo – SP, Brazil, ZIP Code 05508-900

**Integrated Planning Production Group
Samarco Mineração SA
email: rcbotter@usp.br

Keywords: Port Planning, Time Windows, Discrete Simulation

ABSTRACT

A detailed analysis on the historical data base of an iron
ore export terminal showed that laydays concentrate on
the first or the last two weeks of each month, that have
been caused an increase in the waiting line, delay in the
loading process and, consequently, an increase in the
demurrage payment .
This work introduces the dynamic time window concept,
which abides by the contract period of 10 and 15 days the
vessels count on to perform port operations, without,
however, fixing these terms strictly in the first and in the
last half of each month.
A simulation model was conceived to test the
introduction of this dynamic layday concept, maintaining
the characteristics of arrivals, aiming to assess the levels
of occupation, permanence times and line times of the
vessels in the system.
The model was applied to an iron ore export Brazilian
port system called “Ponta de Ubu” and the results
presented in this work show that there is a substantial
gain with the introduction of the dynamic laydays both
concerning the demurrage payment and decrease in port
occupation, and in providing the port administration with
a better management of the vessels arrival process.