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"ABSTRAKKapal dengan lambung banyak (multihull) telah banyak digunakan untuk sarana transportasi laut, salah satunya adalah kapal berlambung empat (quadramaran). Salah satu konfigurasi kapal quadramaran adalah susunan diamond yang mempunyai dua lambung-dalam (mainhull) dan dua lambung-luar (sidehulls). Secara umum kapal multihull pada kecepatan tinggi mempunyai efisiensi hidrodinamik yang lebih baik dari kapal monohull. Tujuan dari studi ini adalah mengetahui efek yang terjadi khusunya terhadap hambatan total kapal quadramaran akibat dari pergeseran letak lambung-luar secara tranversal dan longitudinal. Menggunakan kapal model dengan dimensi L : 2 m, B : 0.21 m, T : 0.07 m yang diuji pada kolam percobaan pada rentang Fr0.15-0.7, dengan rasio penempatan antar sidehulls terhadap panjang keseluruhan mainhull pada kapal quadraman ini adalah S/L=6/41 – 7/41 dan R/L=3/82 – 7/82. Nilai hambatan total didapat dengan menghitung gaya yang diukur oleh load cells transducer. Dari percobaan ini didapatkan efek pergeseran lambung pada rasio S/L=7/41 dan R/L=3/82 mempunyai pengurangan hambatan sebesar 19.09% dan faktor interferensi terbaik 0.26 pada Fr=0.7.

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ABSTRACTShip with multihull has been widely used for sea transportation, one of which has have four hulls or quadramaran ship. One of quadramaran configuration is a diamond, it has two hulls which are main-hull and side-hulls. In general, multihull vessels at high speeds have a better hydrodynamic efficiency than a monohull. The purpose of this study is to identify the possible effect and influence on the ship resistance of quadramaran with separation and staggered hull configuration which the dimension of each hull is L: 2 m, B: 0:21 m, T: 0:07 m. And tested in a towing test using speed variation at Fr between 0.15-0.7. The ratio between side-hulls placement and the overall length of the main-hull is S/L= 6/41 - 7/41 and R/L= 3/82 - 7/82. The total resistance value is obtained by calculating the force measured by load cells transducer. The experiments result find that the effective drag reduction can be archived up to 19.09% and interference factors up to 0.26 with S/L= 7/41 and R/L= 3/82 at Fr=0.7.;;"

"The relative significance ofthe parallel middle body and stern form in the wake formation of single-screwlarge ships and their contribution to the ship?s viscous resistance are studied by using computational fluid dynamics (CFD). A10450-DWT tanker is considered by varying the ratio of theparallel-middle-body?s length to the ship?s length (Lmb/L) and by varying the shape of the stern form from aV-like to a U-like underwater stern transom section. In all the calculations,the principal dimension and the displacement of the ships are kept constant. Alarger value for the parallel-middle-body relative length (Lmb/L) of ships with the same stern form results in alarger drag coefficient but does not affect the nominal wake fractionsignificantly. A change in the shape of the underwater stern form,from a V-like to a U-like section, results in a much larger drag coefficientascribed to the much larger wake fraction. The stern form dominantly affectsthe nominal wake fraction and the ship?s viscous resistance compared to theparallel-middle-body relative length."

"Peningkatan kecepatan kapal dengan daya yang sama merupakan peningkatan efektivitas dan memberikan konservasi energi dalam perjalanan kapal. Dewasa ini telah dipelajari bahwa kecepatan kapal dapat ditingkatkan dengan melakukan biomimetic kulit ikan hiu pada lambungnya. Modifikasi yang lebih dikenal dengan teknologi mikro-riblet ini, memiliki bentuk pola bilik ndash; bilik yang dapat mengarahkan aliran disekitar kapal menjadi aliran turbulen yang teratur. Dalam aplikasinya micro-riblet akan memberikan luasan basah tambahan pada kapal yang dapat meningkatkan hambatan kapal, namun dengan manfaat riblet dalam resistance reduction dan melakukan pengujian riblet berdiameter 220 m dan 150 m didapatkan ukuran riblet dengan efisiensi optimum pada diameter 220 m dengan range efektivitas kecepatan 6.4 -11.4 , dibandingkan diameter 150 m. dengan range efektivitas kecepatan 3 -7.

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The enhancement of ship speed with the same power can give energy conservation in a ship rsquo trip. Nowadays, it has been studied that application of shark skin biomimetic can enhance the ship speed. This modification, better known as micro riblet technology, has a straight pattern that can turn flow around the ship to become well run turbulent flow. In its application, micro riblet gives more wetted surfaced area in the ship rsquo s surface that will increase the ship resistance, but with the benefit of the micro riblet pattern in resistance reduction and riblet trials with the diameter size of 220 m and 150 m it is found the optimum efficiency of micro riblet size with 220 m of diameter and 6.4 11.4 of speed effectiveness range in compared to 150 m with 3 7 of speed effectiveness range."

"Kapal multihull memiliki beberapa keunggulan dibandingkan kapal monohull dalam hal stabilitas yang baik, draft yang lebih kecil, dan area dek yang lebih luas. Kapal multihull juga memiliki area permukaan basah yang lebih besar daripada kapal monohull, namun, resistensi yang dihasilkan tetap lebih kecil karena gangguan gelombang yang dihasilkan oleh masing-masing lambung. Tujuan dari penelitian ini adalah untuk menemukan resistansi total dengan variasi kecepatan dan konfigurasi yang berbeda. Untuk menentukan nilai resistansi, sebuah studi variasi dalam kecepatan dan konfigurasi lambung dilakukan berdasarkan pemeriksaan model kapal trimaran. Pemeriksaan dilakukan pada skala fisik berdasarkan metode Froude dengan eksperimen. Perubahan kecepatan dan konfigurasi bentuk lambung kapal Trimaran penting bagi komponen resistansi kapal. Konfigurasi hull trimaran yang optimal akan meningkatkan gaya angkat ke mainhull sehingga area lahan basah semakin kecil dan tahanan semakin kecil.

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Multihull vessels have several advantages over than monohull vessels in terms of good stability, smaller drafts, and wider deck areas. Multihull vessels also have a larger wet surface area than monohull vessels, however, the resulting resistance remain smaller due to wave interference generated by each hull. The purpose of this study is to find a total resistance with different variations of speed and configuration. To determine the resistance value, a study of variations in speed and configuration of the hull was carried out based on the examination of trimaran ship models. The examination carried out on a physical scale based on the Froude method with experiments. Changes in the speed and configuration of the hull shape on the Trimaran ship are significant to the ship's resistance component. The optimal trimaran hull configuration will increase the lift force to the mainhull that the wet field area gets smaller and the resistance is getting smaller."

"The relative significance of the parallel middle body and stern form in the wake formation of single-screw large ships and their contribution to the ship’s viscous resistance are studied by using computational fluid dynamics (CFD). A 10450-DWT tanker is considered by varying the ratio of the parallel-middle-body’s length to the ship’s length (Lmb/L) and by varying the shape of the stern form from a V-like to a U-like underwater stern transom section. In all the calculations, the principal dimension and the displacement of the ships are kept constant. A larger value for the parallel-middle-body relative length (Lmb/L) of ships with the same stern form results in a larger drag coefficient but does not affect the nominal wake fraction significantly. A change in the shape of the underwater stern form, from a V-like to a U-like section, results in a much larger drag coefficient ascribed to the much larger wake fraction. The stern form dominantly affects the nominal wake fraction and the ship’s viscous resistance compared to the parallel-middle-body relative length."

"Salah satu aspek paling esensial dalam kapal adalah hambatannya. Telah dilakukan riset-riset untuk menganalisis reduksi hambatan dalam rangka mendapatkan performa yang baik; ternyata multihull masih menjadi salah satu bahasan untuk mendapat konfigurasi terbaik yang menarik mdash;untuk menghasilkan hambatan yang kecil. Riset ini adalah studi eksperimental untuk mendapatkan konfigurasi paling bagus mdash;yang melibatkan stagger, clearance dan trim dari jenis lambung pentamaran dengan formasi trimaran menggunakan lambung utama transom dan lambung sisi campuran Wigley-transom. Tujuan dari riset ini juga untuk menentukan efek destruktif dari interferensi gelombang. Pengambilan data dilakukan dengan mengatur stagger rasio jarak antara panjang membujur side hull terhadap main hull, dihitung dari buritan kapal model yang variasinya 0,35 dan 0,4. Untuk clearance rasio jarak antara lebar melintang side hull terhadap main hull, dihitung dari lebar terluar kapal model pada setiap sisinya variasinya yaitu 1,05; 1,20; 1,35; dan 1,50. Variasi trim yang diteliti adalah 0; -0,5; dan -1,0. Hasil pengujian data akan ditampilkan dalam bentuk tabel dan grafik komponen-komponen hambatan dan posisi terbaik konfigurasi, dilihat dari posisi stagger dan clearance-nya.

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One of the most essential aspects of ship is its resistance. There have been done researches to analyze the reduction of resistance in order to get a good performance yet the multihull is still one of interesting researches to get the rightest configuration, as to produce minimum resistance. This research is experimental study to obtain optimum configuration mdash consisting of stagger, clearance and trim of pentamaran with trimaran formation using Wigley transom main hull and non transom side hull.

Its purpose is also to determine the destructive effects caused by wave interference. The research test will be on stagger a ratio of distance of stern main hull to stern side hull to main hull length positioning variations of 0.35 and 0.4. As for clearance a ration of distance centerline of main hull to centerline of side hull to main hull width positioning variations, they will exceed 1.05 1.20 1.35 and 1.50. The trim variations researched are 0o 0.5 o and 1.0 o . The result of this study will be presented by tables and graphs of resistance components and optimum position of side hull on stagger and clearance."

"Indonesia sebagai negara kepulauan memiliki potensi dalam pembangunan nasional. Salah satunya adalah dengan adanya industri perkapalan. Pada industri perkapalan, pengurangan hambatan pada kapal akan mengurangi energi yang dibutuhkan pada kapal dan akan mengurangi emisi CO2. Pengurangan hambatan dilakakukan dengan penambahan appendix berupa stern foil pada kapal. Stern foil digunakan untuk memberikan gaya angkat dan gaya dorong pada kapal untuk mengurangi hambatan. Desain stern foil yang digunakan adalah profil NACA 4412. Tujuan penelitian ini adalah mengetahui kondisi operasi stern foil pada high speed craft dengan simulasi computational fluid dynamics. Peneliti melakukan penelitian ini untuk mendapatkan data hambatan kapal dengan variabel posisi kedalaman stern foil dengan variasi kecepatan. Metode simulasi digunakan untuk memprediksi hambatan kapal pada kapal dengan variasi kecepatan. Penelitian ini menggunakan software CFDSOF untuk melakukan simulasi. Hasil simulasi adalah berupa data hambatan total (N) kapal dengan variasi kecepatan yang direpresentasikan dengan Froude Number (Fn). Pada penelitian ini, kapal model yang digunakan memiliki panjang 1 m dengan variasi posisi stern foil di kedalaman 4 cm, 5 cm, 6 cm, dan di belakang transom di kedalaman 4 cm. Hasil penelitian ini menunjukan pengaplikasian paling optimal dari stern foil mengurangi hambatan kapal sebesar 21% - 29% di Froude Number 0.52 – 0.76.Indonesia as an archipelago has potential in national development. One of them is with the shipping industry. In the shipping industry, reducing ship resistance will reduce the energy needed on ships and will reduce CO2 emissions. Reduction of ship resistance was carried out by adding appendixes in the form of stern foil to the ship. Stern foil is used to provide lift and thrust to the ship to reduce drag. The design of the stern foil used was the NACA 4412 profile. The purpose of this study was to determine the operating conditions of the stern foil at high speed craft with computational fluid dynamics simulations. Researchers conducted this study to obtain data on ship resistance with stern foil depth position variables with speed variations. The simulation method is used to predict ship resistance on ships with speed variations. This study uses CFDSOF software to conduct simulations. The simulation results are in the form of total resistance data (N) of ships with speed variations represented by Froude Number (Fn). In this study, the model ship used has a length of 1 m with a variation of the stern foil position at a depth of 4 cm, 5 cm, 6 cm, and behind the transom at a depth of 4 cm. The results of this study indicate that the most optimal application of stern foil reduces ship resistance by 21% - 29% in Froude Number 0.52 - 0.76."

"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."