As an archipelagic country, Indonesia needs ferry transportation to connect and support the economic activities between areas bounded by the sea. The famous crossing route is the Merak–Bakauheni one, which connects the Java and Sumatra economic corridors. Many ships operate on this route, but limited port facilities significantly affect the efficiencies of the services provided, hence, they have to be moved. Therefore, this research analyzed the suitability of ships to operate on the eastern crossing. The analysis method used the financial aspect (revenue) feasibility, the suitability of the port infrastructure, and the oceanographic conditions. The financial analysis used the ships’ operating cost method to determine the crossing passage rates based on their specifications. It simulated the ships with various load factors to identify potential gains or losses. Furthermore, the infrastructure suitability analysis used the under keel clearance and comparative methods to compare the suitability of the ship dimensions and tonnage with the port infrastructure capacity. The oceanographic analysis used the Weibull method to simulate the redefinition of the distribution of significant wave heights, which was compared with the ratio of the ship dimensions and wave slope to determine its heel angle using the IMO Weather Criterion method (IS Code 2008). The results showed that the relocation of ships from the Merak–Bakauheni route directly to Eastern Indonesia through the existing crossing routes is feasible from the aspect of shipping safety, but it is not feasible financially or in terms of infrastructure. The Benoa–Labuan Bajo route is a potential new route recommendation, with regulatory support for the operation of ships in the form of tariffs and operational costs, and it permits the use of subsidized fuel. On the other hand, ship owners must consider modifying the ramp door to suit the port wharf structure.

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Rubble mount breakwateris recently become the most widely used breakwater, consist both of natural and artificial stone. It required a large dimension of structure so that the investment costs become more and more expensive. One of the solutions that can be implemented is Hanging Sheet Pile breakwater. Unfortunately, the performance of this type of breakwater has not been known yet. Performance of this breakwater represented by wave energy transmission coefficient (KEt). Therefore, this study aims to examine the effect of relative draft (s/d) and relative wave height (H/s) to KEt. This study conducted in Ocean Technology Laboratory of Universitas Hasanuddin. The parameters studied are structure dimensions and wave parameters. Wave parameters consist of wave height (H) and wave period (T), while the structure parameter is the draft structure (D). The result of this study shows that the greater value of both incident wave steepness (Hi/gT2) and structure relative draft (s/d), then the smaller of KEt value will be achieved. Also, the greater relative H/s, the smaller KEt will be achieved. For all cases of study, the transmission coefficient ranges from 0.122 – 0.786.

Ro-Ro ship has special characteristic for cargo handling because the cargo is transferred in horizontal direction. For example, cars can move by using ramp door which is located in front and/or aft of the ship. In conjunction with this, car passenger and other decks such as top including bottom part need to be investigated for local and global of Ro-Ro ship structure. In the present study, the ultimate strength investigation of Ro-Ro ship is conducted. There are three types of Ro-Ro ships are taken as the ship’s subject. The cross section of Ro-Ro is considered in the analysis and it is modelled having plate and stiffened plate. The one-frame is represented in longitudinal direction. The simply supported of boundary condition is applied and the cross section is assumed to be remained plane. The calculation of the ultimate strength using in-house integrated program. The ultimate strength of Ro-Ro ship is investigated under hogging and sagging conditions. The vertical bending moment is imposed to the cross section to obtain the ultimate strength including their progressive collapse. The result obtained by in-house program for three types of Ro-Ro ships are summarized and the collapse behaviour for local and global of the decks to the ultimate strength of Ro-Ro ship are also presented in this study.

Erosion and sedimentation problems that occurs, usually solved firstly by finding the cause of erosion and sedimentation literally, due to determining the action to overcome them. In coastal engineering, there are two approaches that can be used to solve such kind of problems; which are the soft approach, i.e. beach nourishment, vegetation, sand by passing, coastal boundary policy; while the hard approach or structural approach are building breakwater, jetty, groin, sea wall and so on. In structural approach, the uses of permeable groin nowadays is one of the new ways to overcome the erosion and sedimentation problems in beaches. To find out how efficient the permeable groin can control the flow along the coast, so called longshore current, a research needed to be conducted focusing on the effect of pole density at permeable groin itself. The ability of controlling longshore current will be the main analysis, in such various variations of pole densities at the permeable groin. It found out that the pole densities of permeable groin can significantly controlled the longshore current; which is if the pole density become higher than the speed of longshore current can be reduced. It also found out that by implementing 40% of pole density, the longshore current can be reduce up 50% respectively.