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KAPAL Jurnal Ilmu Pengetahuan dan Teknologi Kelautan

KAPAL
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Published by Universitas Diponegoro

ISSN : 18298370 EISSN : 23019069 DOI : 10.14710/kapal.

Core Subject : Science,

Earth & Planetary Sciences

Jurnal ini merupakan Jurnal Ilmiah untuk mengembangkan ilmu dibidang Ilmu Pengetahuan & Teknologi Kelautan. Jurnal ini diterbitkan oleh Teknik Perkapalan Universitas Diponegoro 3 (tiga) kali dalam 1 tahun pada bulan Februari, Juni dan Oktober.

Arjuna Subject : -

Articles 408 Documents

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Design of River Tour Boat’s Hull For Taman Nasional Tanjung Puting, Central Borneo Danu Utama; Ahmad Nasirudin; Muhammad Iqbal
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 1 (2020): February
Publisher : Department of Naval Architecture - Diponegoro University

Tanjung Puting National Park is a natural wildlife park with a positively increasing trend in the number of visitors. The transportation which is utilized in Sekonyer river is ‘klotok’ boat, a traditional tour boat modified from a fishing boat. The design of a fiberglass-based tour boat is needed to accommodate the limitation of Kalimantan’s logs, which become the main structural components of klotok and to comply with the technical characteristic of the river. The purpose of this study is to obtain the optimum main dimensions of the fiberglass-based tour boat and its hull form design. The method performed to obtain the main dimension of the boat is non-linear optimization with the help of solver in Microsoft Excel software. The process of boat’s hull design is done by line distortion approach where the shape of a reference boat’s hull is conformed to a particular size and hydrodynamical coefficients, which are obtained from the optimization process. The result of optimization process is the main dimension of the boat (Lpp = 12.23 m, B = 2.70 m, H = 1.14 m, T = 0.80 m and Cb = 0.55). By conducting a series of calculations, the obtained value of the total boat’s resistance worths 2,427 N. Therefore, the number of boat’s power needed is less than the power of existing boats. The boat’s hull also complies with technical requirements and regulations, which are freeboard and intact stability.

Estimation of Effective Wave Slope Coefficient of Ships with Large Breadth and Draught Ratio Paroka, Daeng; Muhammad, Andi Haris; Rahman, Sabaruddin
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 1 (2020): February
Publisher : Department of Naval Architecture - Diponegoro University

One of parameters to estimate heel angle of a ship in beam seas is effective wave slope coefficient. In the weather criterion of IMO, the effective wave slope coefficient is determined as function of ratio between distance of center of gravity from the sea surface and the ship draught. The others methods could be used to estimate the effective wave slope coefficient are simplified strip theory and model experiment. A ship with shallow draught and large vertical center of gravity can have an effective wave slope coefficient larger than 1.0 if the coefficient is calculated by using the formulae of weather criterion. Therefore, an alternative method to estimate the coefficient is necessary when it is applied to ships with geometry characteristics different with those used to develop the formulae. This research conducts to estimate the effective wave slope coefficient using three different methods, namely the formulae of weather criterion, the simplified strip theory and model experiment. Results of the three methods may provide enough evidence about suitable method to estimate the effective wave slope coefficient of ships with breadth and draught ratio larger than 3.5 like the Indonesian ro-ro ferries. Results and discussion show that the effective wave slope coefficient obtained by using the formulae of weather criterion is larger compared to that obtained by using the simplified strip theory and the model experiment. Here, the result of simplified strip theory for wave frequency the same as the roll natural frequency of subject ship is similar with the result of model experiment. This results show that the simplified strip theory can be used as an alternative method to determine the effective wave slope of a ship with breadth and draught ratio larger than 3.5 if the result of model experiment does not available.

Hybrid Propulsion System (PV / Gasoline) For Small Fishing Vessels Sultoni, Arif Indro; Ali, M. Marhaendra; Aji, Zaenal Panutup
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 1 (2020): February
Publisher : Department of Naval Architecture - Diponegoro University

The mechanism of hybrid (PV+gasoline) for fishing vessel propulsion was aimed to reduce fuel consumption.Â The background of this research is lots of vessels not going for fishing because of a lack of fuel. With the hybrid mechanism, the fishing vessels could less fuel consumption without decreases its performance (torsion, power durability, and velocity) when cruising. In this paper, a parallel hybrid (PV/gasoline) is proposed. The gasoline generator will deliver power to DC motor if PV energy that stored to the battery not enough as the requirement of propeller propulsion. Hybrid design for a 3-ton overall weight of fishing vessel was designed with eight-unit solar panels @200 WP arranged as four string-2 series. Li-Ion battery pack with 4.5 KWH of capacity was used as energy storage. The simulation shows that the hybrid scheme can preserve the vessel speed at 16 Km per hour with time duration in 12 hours 46 minutes and needs 4 hours 10 minutes for full battery charging by a gasoline generator.

Back-Matter V. 17, No. 1 Muhammad Iqbal
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 1 (2020): February
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2053.791 KB)

Performance Improvement of Hopper Cooling System on Traditional Fishing Boats Due to Excessive Cooling Koenhardono, Eddy Setyo
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 2 (2020): June
Publisher : Department of Naval Architecture - Diponegoro University

The engine cooling system that drives traditional fishing boats uses a hopper cooler type system that experiences excessive cooling. Ideally, the temperature of the cooling water in the hopper should be approximately 70-80Â°C. The fact, it is only 42Â°C, thus reducing the effective power generated by the engine. This excessive cooling may cause an increase in fuel consumption and emissions. One method to reduce excessive cooling is to increase the temperature of the cooling media in the hopper. Â The author has conducted a simple experiment on a traditional fishing boat in Kenjeran, Surabaya, by installing a valve to control the flow of seawater entering the hopper. However, the use of seawater as a cooling medium has a maximum operating temperature limitation, so there is no precipitation of salt and lime, which is 50oC. At this temperature, the benefits are not large, only an increase in speed of 4.4% and a fuel reduction of 4.3%. Therefore, the existing seawater cooling system must be modified to an indirect seawater cooling system to get optimum performance improvement. The re-modification allows the temperature of the freshwater in the hopper to be maintained at 80Â°C, so that the speed of the fishing boat may increase by 14%, with a fuel savings of 12.3%.

Sloshing Simulation of Single-Phase and Two-Phase SPH using DualSPHysics Trimulyono, Andi; Samuel, S; Iqbal, Muhammad
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 2 (2020): June
Publisher : Department of Naval Architecture - Diponegoro University

The sloshing phenomenon is one of the free surface flow that can endanger liquid cargo carriers such as ships. Sloshing is defined as the resonance of fluid inside a tank caused by external oscillation. When sloshing is close to the natural frequency of the tank it could endanger ships. Particle method has the advantages to be applied because sloshing is dealing with free surface. One of the particle methods is Smoothed Particle Hydrodynamics (SPH). In this study, compressible SPH was used as a result of the pressure oscillation, which exists because of the effect of density fluctuation as nature of weakly compressible SPH. To reduce pressure noise, a filtering method, Low Pass Filter,Â was used to overcome pressure oscillation. Three pressure sensors were used in the sloshing experiment with a combination of motions and filling ratios. Only one pressure sensor located in the bottom was used to validate the numerical results. A set of SPH parameters were derived that fit for the sloshing problem. The SPH results show a good agreement with the experimentâ€™s. The difference between SPH and experiment is under 1 % for sway, but a larger difference shows in roll. Low pass filter technique could reduce pressure noise, but comprehensive method needs to develop for general implementation.

Wind Tunnel Investigation into the Resistance Analysis of Slender Body Catamaran Utama, I Ketut Aria Pria; Sutiyo, S; Suwasono, Bagiyo
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 2 (2020): June
Publisher : Department of Naval Architecture - Diponegoro University

The Wind tunnel investigation of a slender body catamaran was conducted in order to determine its resistance characteristics, namely the effect of pressure and flow velocity changes for varied hull separation. The catamaran was tested in a wind tunnel belongs to Department of Mechanical Engineering, ITS, with hull separations ofÂ S/L = 0.2 to 0.4 and variation in Reynolds numbers up to 4.46 x 105. Pressure around the hull was measured using pressure tappings and the flow velocity behind the hull was also measured using a PitÃ´t-static tube. The experimental study shows that the pressure coefficient decreases when the hull separation declines and conversely, the flow velocity increases. The tests demonstrated a viscous interaction between the hulls, and form factors for the monohull and catamaran are derived. The demihull exhibited a form factor (1+k) of 1.265 and in the catamaran mode, the measured form factor (1+Î²k) was between 1.416 and 1.403. The results are in agreement with other published data.

Strategy for Improving the Competitiveness of Shipyards in the Eastern Part of Indonesia Baso, Suandar; Musrina, M; Anggriani, Andi Dian Eka
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 2 (2020): June
Publisher : Department of Naval Architecture - Diponegoro University

In recent years, the number of shipyards in Indonesia has increased significantly to anticipate the increasing demand and the government policy regarding the Cabotage Principles and Masterplan for Acceleration and Expansion of Indonesiaâ€™s Economic Development (MAEIED), and three Archipelagic Sea-Lanes (ASLâ€™s) in Indonesia. However, shipbuilding and ship repair works have been centered in the western part of Indonesia. Therefore, this study aims to develop a potential strategy of shipyards in the eastern part of Indonesia to compete in the current market situation. The Analytical Hierarchy Process (AHP) method was used to model the strategy hierarchy and analyze the weight of sub-criteria as the internal and external factors of the shipyard competitiveness. Then, the Blue Ocean Strategy method was used to analyze the competitiveness strategy. To improve competitiveness, the shipbuilding industries in the eastern part of Indonesia have to focus intensively on reforming and upgrading several internal environment factors such as coordination and response, business network, high skill manpower, and complex ship types building ability. Besides, the shipyards also have to focus on external environmental factors, particularly on five factors that have a high influence on improving competitiveness, namely shipping company partners, networks and partnership with suppliers, government policies, human resource development, and cluster formation of shipyards.

Analysis of Fatigue Life of Tugboat Towing Hook Construction Using Finite Element Method Adnyani, Luh Putri; Arsyad, Muhammad Abid Mapariorio; Nurcholik, Samsu Dlukha
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 17, No 2 (2020): June
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/kapal.v17i2.29587

The towing hook on the tugboat has a function to pull the barge. Because of this ability, a good towing hook construction is needed to work optimally. Indications for the good construction is the value of fatigue life, which is more than the value of design life of 20 years. A towing hook detail on tugboat from PT. Asia Aditama Shipyard â€“ Balikpapan was selected as an example. This study aims to obtain the value of fatigue life based on the total resistance calculated by BHP data in full, 75%, and 50% of the total displacement volume and estimate the maximum size of a barge, based on maximal towing pull capacity. The benefits of this research are providing information about the fatigue life of a towing hook, analyzing several possible load cases, and giving the recommendation of the maximum principal dimensions of the barge that the towing hook can be pulled. The method used in this study is the finite element method using ANSYS, the fatigue life calculation approach is the Palmgrenâ€“Miner cumulative damage method and refers to the DNVGL rule. The results of the calculation of fatigue life in the maximum towing pull condition are 22 years, 22 years, and 23 years at 100%, 75%, and 50%, respectively. The main size of barges that can be towed by Tugboats under maximum towing pull conditions are LOA = 147m, LWL = 144,529m, B = 35m, H = 13m, T = 11m.

Transmission Coefficient Analysis of Notched Shape Floating Breakwater Using Volume of Fluid Method: A Numerical Study Ridlwan, Asfarur; Armono, Haryo Dwito; Rahmawati, Shade; Tuswan, Tuswan
Kapal: Jurnal Ilmu Pengetahuan dan Teknologi Kelautan Vol 18, No 1 (2021): February
Publisher : Department of Naval Architecture - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/kapal.v18i1.34964

As one of the coastal structures, breakwaters are built to protect the coastal area against waves. The current application of breakwaters is usually conventional breakwaters, such as the rubble mound type. Climate change, which causes tidal variations, sea level height, and unsuitable soil conditions that cause large structural loads, can be solved more economically by employing floating breakwater. In this study, numerical simulations will be conducted by exploring the optimum floating breakwater notched shapes from the Christensen experiment. The comparison of three proposed floating breakwater models, such as square notch (SQ), circular notch (CN), and triangular notch (VN), is compared with standard pontoon (RG) to optimize the transmission coefficient value is analyzed. Numerical simulations are conducted using Computational Fluid Dynamics (CFD) based on the VOF method with Flow 3D Software. Compared to the experimental study, the RG model's validation shows a good result with an error rate of 8.5%. The comparative results of the floating breakwater models are found that the smaller the transmission coefficient value, the more optimal the model. The SQ structure has the smallest transmission coefficient of 0.6248. It can be summarized that the SQ model is the most optimal floating breakwater structure.

Page 27 of 41 | Total Record : 408

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