Mathematical Model Development to Estimate Gross Tonnage of Ro-Ro Ferry Syamsul Asri Lecturer at Naval Architecture Study Program Faculty of Engineering Hasanuddin University Makassar, Indonesia Wahyuddin Lecturer at Naval Architecture Study Program Faculty of Engineering Hasanuddin University Makassar, Indonesia Mohammad Rizal Firmansyah Lecturer at Naval Architecture Study Program Faculty of Engineering Hasanuddin University Makassar, Indonesia Abd. Haris Djalante Lecturer at Naval Architecture Study Program Faculty of Engineering Hasanuddin University Makassar, Indonesia Abstract— This paper introduces an approach to estimate gross tonnage of Ro-Ro Ferry. The approach was formulated from the analysis result of data of tonnage and main dimensions of Ro-Ro Ferries which operated in Indonesia in 2012. The result obtained is a mathematical model to estimate gross tonnage of Ro-Ro Ferry as a function of the tonnage volume. Tonnage volume consists of hull and superstructure volume. The volume of hull was formulated as a function of main dimensions and form coefficient of ship hull while volume of superstructure was formulated as a function of length between perpendiculars (LBP), breadth (B), and cumulative height of superstructure (HS). This equation can be used to estimate the gross tonnage of Ro-Ro Ferry in the preliminary design stage as well as an initial reference to the ship measurement by ship surveyors. Keywords— Mathematical Model; Ro-Ro Ferries; Tonnage I. INTRODUCTION Indonesian government has organized ferry transport service by placing the ships to be operated regularly at some certain routes. As a rule, the ship type to be used is Ro-Ro Ferry for transporting passengers, vehicles and their cargo. In a Decree of Minister of Transportation of Republic of Indonesia Number KM 53 of 2002 on the National Order of Port Affairs [1]; Article 22, regarding Ferry Port class, Ro-Ro Ferry was classified into three groups of gross tonnage (GT). The first port class for the ships with tonnage less than 500 GT, the 2nd port class for ship with tonnage between 500 GT and 1000 GT, and the 3rd port class for ship with tonnage more than 1000 GT until 1500 GT. Under the terms of Article 2 of the Regulation of the Minister of Transportation of the Republic of Indonesia Number PM 8 Year 2013 about Ship Measurement [2], any ship prior to be operated must be measured to determine the length, breadth, height, and its tonnage. Tonnage is the volume of the ship expressed in (gross tonnage (GT) and net tonnage (NT). Prior to the enactment of legislation of the Regulation of the Minister of Transportation of the Republic of Indonesia Number PM 8 Year 2013, ship tonnage measurement in Indonesia is based on the Regulation of the Minister of Transportation of the Republic of Indonesia Number KM 6 of 2005. Before 2005, the measurement of ships tonnage is based on a number of regulations about ships tonnage. For ships with a length of 24 meters or more, its tonnage determined based on the international measurement method which recommended in International Convention on Tonnage Measurement of Ships, 1969. Based on the data of Ro-Ro Ferries tonnage which is operated in Indonesia in 2012, there are several ships which have the same main dimension but different tonnages. In addition, there are some other ships with smaller main dimensions but have a greater tonnage than the other ships that have larger main dimensions. In principle, the amount of ship tonnage is the result of multiplying factor K1 with the tonnage volume (VT). Factor K1 is expressed as a logarithmic function of the tonnage volume. Tonnage volume consists of hull volume and superstructure volume. This paper has developed a mathematical model to estimate the gross tonnage of Ro-Ro Ferry based on tonnage volume (VT) information. The equation of tonnage volume is formulated as a function of its main dimensions. This equation can be used to estimate the gross tonnage of Ro-Ro Ferry in the preliminary design stage as well as an initial reference to the ship measurement by ship surveyors. II. RESEARCH METHODS The number of ships to be observed in this research was 206 ships of 219 Ro-Ro Ferry which operated to serve ferry transport in Indonesia in 2012. The data of tonnage and main dimensions of sample ships were collected from document of The Map of Ferry Route [3]. There are varying sample ships with different main dimension and tonnage. The development of mathematical model to estimate the gross tonnage of Ro-Ro Ferry was based on the tonnage and main dimension of ships sample. The development was divided into four steps which are determination of tonnage volume, determination of ship hull volume, determination of superstructure volume, and formulation of ship gross tonnage estimation. According to the terms of Rule 22 in Annex I of the Regulation of the Minister of Transportation of the Republic of Indonesia, PP No. 8 Year 2013 about The Ships Measurement [2], ships gross tonnage (GT) can be obtained by multiplying factor K1 to the tonnage volume (VT). Tonnage volume consists of volume of submerged hull and volume of superstructure including deck house volume. International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 http://www.ijert.org IJERTV5IS120098 Vol. 5 Issue 12, December-2016 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Published by : www.ijert.org 104