Keywords: Sea Surface Temperature, Algorithm, Landsat 8 TIRS, Poteran Island Water The Sea Surface Temperature (SST) retrieval from satellites data Thus, it could provide SST data for a long time. Since, the algorithms of SST estimation by using Landsat 8 Thermal Band are sitedependence, we need to develop an applicable algorithm in Indonesian water. The aim of this research was to develop SST algorithms in the North Java Island Water. The data used are in-situ data measured on April 22, 2015 and also estimated brightness temperature data from Landsat 8 Thermal Band Image (band 10 and band 11). The algorithm was established using 45 data by assessing the relation of measured in-situ data and estimated brightness temperature. Then, the algorithm was validated by using another 40 points. The results showed that the good performance of the sea surface temperature algorithm with coefficient of determination (R²) and Root Mean Square Error (RMSE) of 0.912 and 0.028, respectively.

In the operation of floatplanes, porpoising must be avoided, but it is a common occurrence during takeoff, as it induces longitudinal instability and compromises the safety and comfort of passengers. The mechanism of porpoising and the factors or variables that influence the occurrence of this phenomenon are explored in this study. Based on a review of the literature, the position of the longitudinal center of gravity (LCG) and the deadrise angle were found to be the two most significant variables affecting the porpoising phenomenon. The mechanism of porpoising was simulated using a numerical model based on computational fluid dynamics (CFD). The simulation findings were then compared to the results of a related model’s towing tank experiment. With five velocity differences, a validated computational model was used to analyze the impact of LCG ordinates and deadrise angles on the frequency of porpoising. Compared to the LCG 50% length overall (LOA) configuration, the floater with an LCG 53% LOA configuration caused a higher heave porpoising amplitude by 4% for the floater with a 10° deadrise angle and 1% for the floater with a 20° deadrise angle at all speed variations. However, the pitch porpoising amplitude produced by the floater with an LCG 53% LOA configuration was found to be 4% higher than the LCG 50% LOA configuration for the floater with a 10° deadrise angle and -1% higher than the LCG 50% LOA configuration for the floater with a 20° deadrise angle. The results showed that the higher heave and pitch porpoising amplitude was generated by a low deadrise angle and a shift in the floater’s center of gravity toward the bow.

The water impact at the bottom of a floatplane upon landing is one of the biggest concerns related to the structure strength. The free fall of the floater to the water's surface is ideal for modelling to acquire a pressure value against the optimal design angle of the deadrise and flare. The impact pressure due to free-falling of the 2D cross-section of the floater at four different deadrise angles is computed using the computational fluid dynamics (CFD) technique in FLUENT's dynamic mesh feature. According to the simulation results, the angle of deadrise impacts the pressure on the floater bottom area that decreases along with the increase in deadrise angle. Flares also help to lessen the pressure value under all deadrise angle scenarios. All models have good agreement when compared to the modified Wagner's formula, with an average inaccuracy of roughly 5.27 percent.

It is necessary for the ship to have the capability of maneuvering when it is operating out at sea in order to protect the ship from the risk of colliding with other objects. To increase maneuverability, it is proposed to deploy interceptor devices on the two sides of the ship's stern, where the height of the interceptor blades can be adjusted. The working principle is to restrict the flow of fluid on one side at the stern in order to generate greater pressure than the other side, so that the fluid flowing towards the stern of the ship experiences a high-speed difference between one side and the other, resulting in an increase in side force. In this paper, the open free-running test method is used to test the interceptor's ability to turn on a model of a fast ship. The ship model is fitted with a GPS device, a control system, a motor, and a communication system. The case study of the interceptor mounted on two distinct sides at the ship's stern is conducted with various combinations of interceptor blade height (d) between the two sides, including 100% d, 50% d, and 0% d. The test findings consist of model trajectory, velocity, and an IMO standard maneuver. The combination of 100% d at portside, 0% d at starboard side, and the rudder pointing portside at 35 degrees angle resulted in the best tactical diameter, which is 21.49% smaller than without the interceptor.

The prioritization of naval vessel construction in Indonesia underscores the nation's commitment to safeguarding its territorial waters. As part of this endeavour, optimizing ship hull design is essential to ensure safety, efficacy and minimize environmental impacts. In line with this objective, Indonesia is currently developing a tank-boat with a catamaran hull configuration, meticulously engineered to navigate diverse maritime environments, from shallow waters to deep seas. To evaluate the performance of this innovative vessel, Computational Fluid Dynamics (CFD) is employed for both numerical analysis and practical testing in still-water conditions across various scenarios. The study investigates the effects of lateral separation ratios (S/L) ranging from 0.2 to 0.4 and speed fluctuations represented by the Froude Number spanning from 0.1 to 1.0. The findings from this investigation reveal boat remarkable resilience in still-water situations, particularly when compared to experimental trials. Notably, the results indicate a consistent increase in performance from Froude Number (Fr) 0.1 to 1.0. It is observed that the total resistance coefficient (CT) peaks in still-water conditions at a Froude number (Fr) of 0.5, suggesting optimal performance at this speed. The alignment between CFD predictions and experimental findings, with differences well within acceptable margins, validates the robustness of the computational models. The highest value of the total resistance coefficient (CT) in still water was observed at a Froude number (Fr) of 0.5 across different lateral separation ratios (S/L). It peaked at Fr 0.5 with an S/L of 0.3 in both CFD and experimental analyses. In CFD, the CT value was 18.16 x 10-3, while in the experimental analysis, it was 18.83 x 10-3, indicating discrepancy of 3.68 % which is an excellent agreement between the two methods.