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Abstrak :
The effects of the application of a stern hydrofoil on ship resistance were studied numerically using computational fluid dynamics (CFD) and were verified using data from model tests. A 40 m planing-hull Orela crew boat, with target top speed of 28 knots (Froude number, Fr = 0.73), was considered. The stern foil (NACA 64(1)212) was installed with the leading edge positioned precisely below the transom with angle of attack of 2 degrees at elevation 0.853 T below the water surface (where T is the boat’s draft). At relatively low speed (Fr < ~0.45) the application of a stern foil results in an increase in ship resistance (of up to 13.9%), while at relatively high speed (Fr > ~0.55) it results in a decrease in ship resistance (of up to 10.0%). As the Froude number increases, the resistance coefficient (CT) first increases, reaches a maximum value, and then decreases. Its maximum value occurs at Fr ? 0.5, which is consistent with the prediction of a resistance barrier at approximately this Froude number.

Abstrak :
ABSTRAK
Indonesia telah menjadi poros maritim dunia, yang merupakan salah satu strategi yang ingin diwujudkan oleh Presiden Joko Widodo. Strategi ini memiliki beberapa pilar utama, salah satunya adalah membangun kekuatan pertahanan maritim. Agen keamanan menuntut armada patroli atau kapal perang yang diharuskan memiliki berbagai kemampuan seperti kecepatan tinggi hingga kemampuan manuver yang baik. Namun di sisi lain, kemajuan teknologi yang diterapkan pada kapal membutuhkan bahan bakar primer. Faktanya ketersediaan bahan bakar fosil semakin menurun, sehingga kapal juga membutuhkan efisiensi kapal yang baik. Salah satu solusi untuk masalah ini adalah meningkatkan efisiensi kapal itu sendiri. Salah satu teknologi untuk meningkatkan efisiensi di kapal adalah foil buritan. Foil buritan memiliki prinsip yang sama dengan hydrofoil, tetapi foil buritan hanya ditemukan di buritan kapal. Dengan mengurangi area basah di buritan kapal, secara otomatis akan mengurangi resistensi dan berdampak pada karakteristik kapal. Penelitian tentang penerapan stern foil dilakukan pada model kapal 1 m dengan metode uji derek. Hasil aplikasi stern foil menunjukkan pengurangan total resistansi kapal dengan nilai minimum 14,06% (Fn 0,7), nilai maksimum 41,14% (Fn 1,3), dan pengurangan resistansi rata-rata pada 17,28% (Fn 0.6-1.3).

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ABSTRACT
Indonesia has become the world's maritime axis, which is one of the strategies that President Joko Widodo wants to realize. This strategy has several main pillars, one of which is building maritime defense forces. Security agents demand patrol fleets or warships that are required to have various capabilities such as high speed to good maneuverability. But on the other hand, technological advances applied to ships require primary fuel. The fact is the availability of fossil fuels is decreasing, so ships also need good ship efficiency. One solution to this problem is to improve the efficiency of the ship itself. One technology to improve efficiency on ships is stern foil. Stern foils have the same principles as hydrofoil, but stern foils are only found at ship stern. By reducing the wet area at the stern of the ship, it will automatically reduce resistance and have an impact on the characteristics of the ship. Research on the application of stern foil was carried out on a 1 m ship model with the crane test method. The results of the application of stern foil show a reduction in total ship resistance with a minimum value of 14.06% (Fn 0.7), a maximum value of 41.14% (Fn 1.3), and an average reduction in resistance at 17.28% (Fn 0.6 -1.3).