Journal of Marine Science and Engineering Article Comparing Structural Casualties of the Ro-Ro Vessel Using Straight and Oblique Collision Incidents on the Car Deck Aditya Rio Prabowo 1,* , Dong Myung Bae 2 and Jung Min Sohn 2,* 1 Department of Mechanical Engineering, Universitas Sebelas Maret, Surakarta 57126, Central Java, Indonesia 2 Department of Naval Architecture and Marine Systems Engineering, Pukyong National University, Busan 48513, Korea; [email protected] * Correspondence: [email protected] (A.R.P.); [email protected] (J.M.S.) Received: 24 April 2019; Accepted: 6 June 2019; Published: 11 June 2019 Abstract: Roll on-roll off (Ro-Ro) ship is the preferable vessel for public transportation and also as a medium to distribute several commodities. Its operations are a straightforward process but traffic management is quite delicate, especially for cross-route. Moreover, maritime incidents sometimes occur, causing significant casualties and in the case of the Ro-Ro, collision with other ship is a possible threat with the ability to trigger immense damages. This research, therefore, was conducted to assess the structural casualties of a Ro-Ro vessel under collision. This was modelled with respect to a ship involved in a certain incident in Indonesia in the latest decade, and the designed collision problems were calculated using the finite element approach. The collision angle was selected as the main input parameter with the straight collision of angle 90◦ and oblique collision with different angles applied to the scenario. The results found the collision energy due to structural destruction to have distinct pattern and peak value under oblique cases with lower values observed for straight collision for all scenarios. It is, however, recommended that energy should be taken as an initial parameter in further investigation of structural damage and response contour. Keywords: maritime incidents; straight and oblique collisions; finite element approach; energy ratio; rupture strain 1. Introduction Transportation has been playing an important role in human society, and industrial development since the first industrial revolution took place more than two centuries ago. It started with the use of the animal as the driving force followed by the application of diesel engine in inland, aerospace, and water transportation. Furthermore, human interaction also experiences massive progress, for example, the use of a mobile phone makes it more convenient to communicate over long distances compared to the conventional methods of communication. This was followed by the evolution of these phones to become smart leading to easy business transactions, trading and several other forms of interaction. For the purpose of this study, transportation mode is focused because it requires carrying subjects from one location to the other based on designated missions, for example, it is possible to transport humans and commodities using a public vehicle which is classified as an inland transportation mode. However, most archipelago countries are faced with the challenges of obtaining another transportation mode to transport people on the island and this led to the use of water transportation mode by the public, thereby, making it become one of the highest maritime business potentials in these countries. Consequently, roll on-roll off (Ro-Ro) ship was considered the most suitable vessel in this situation due to its capability to convey a large number of vehicles, passengers, and commodities at the same time to cross the sea or strait. J. Mar. Sci. Eng. 2019, 7, 183; doi:10.3390/jmse7060183 www.mdpi.com/journal/jmse J. Mar. Sci. Eng. 2019, 7, x 2 of 15 business potentials in these countries. Consequently, roll on-roll off (Ro-Ro) ship was considered the J.most Mar. Sci.suitable Eng. 2019 vessel, 7, 183 in this situation due to its capability to convey a large number of vehicles,2 of 15 passengers, and commodities at the same time to cross the sea or strait. The Ro-Ro ship is a vessel with the cargo wheeled or loaded/unloaded on board, in a vehicle or The Ro-Ro ship is a vessel with the cargo wheeled or loaded/unloaded on board, in a vehicle or other platforms equipped with wheels. The first ships to be classified under this category were the other platforms equipped with wheels. The first ships to be classified under this category were the Ferry equipped with railways to allow the transport of train carriages between the margins of the Ferry equipped with railways to allow the transport of train carriages between the margins of the rivers considered too wide for bridges. The use of the Ro-Ro concept in merchant ships started in the rivers considered too wide for bridges. The use of the Ro-Ro concept in merchant ships started in late 1940s, early 1950's and mainly in the short-sea routes, such as inter-island route through the strait the late 1940s, early 1950’s and mainly in the short-sea routes, such as inter-island route through the in archipelago countries. It became a significant vital transportation mode and a traffic connector. strait in archipelago countries. It became a significant vital transportation mode and a traffic connector. Furthermore, Figure 1 shows how the infrastructures for Ro-Ro spread on the islands of Indonesia Furthermore, Figure1 shows how the infrastructures for Ro-Ro spread on the islands of Indonesia thereby making domestic water traffic of the country to be very high. This is also influenced by the thereby making domestic water traffic of the country to be very high. This is also influenced by the use use of the strait between the islands as international route, especially from East Asian countries such of the strait between the islands as international route, especially from East Asian countries such as as South Korea, Japan and China and Southeast Asia including Singapore to reach Australia [1–3]. South Korea, Japan and China and Southeast Asia including Singapore to reach Australia [1–3]. Balikpapan Banda Aceh 10 trajectories Ternate 2 trajectories 8 vessels 16 trajectories 2 ports 2 vessels Batam Bitung 8 vessels 7 trajectories 5 trajectories 3 ports 8 vessels Pontianak 3 vessels Biak 2 ports 10 trajectories 1 port Sorong 7 trajectories Singkil 3 vessels 4 trajectories 7 vessels 18 trajectories 3 vessels 4 vessels Luwuk Padang Batulicin 11 trajectories 4 trajectories 2 trajectories 6 vessels 2 vessels 3 vessels 1 port Ambon 2 ports Surabaya Bajoe 10 trajectories 3 trajectories 10 vessels 3 vessels 1 trajectory 5 ports Bakauheni 2 ports 1 vessel 2 ports 1 trajectory 1 port Merak Merauke Jepara 8 trajectories 1 trajectory Ketapang 2 trajectories 2 vessels 6 vessels 1 trajectory Kupang 2vessels 1 port 2 vessels 21 trajectories 2 ports 7 vessels 3 ports Figure 1. Location of port infrastructure across Indonesia territory (based on information in Ref. [4]). Figure 1. Location of port infrastructure across Indonesia territory (based on information in ref. [4]). 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