In the North Coastal Region of Central Java, the traditional fi shing boat is a primary object that generates the economics activities of the social community. As an artisanal fi shery, the boats generally adopt the tradition to build technique from their predecessor. Therefore the lack of practice to determine the propeller design which considered the hydrodynamic relation within the boat dimension, hull form geometry and propeller is observed. Presently, there is no a standard propeller design that particularly well designed considering the hull shape geometry for the traditional boat. The aim of the research is to identify the propeller that would be applied to the fi shing boats typically found in the North Coastal Region of Central Java using B-Series marine propeller. Computational Fluid Dynamics (CFD) analysis for assessing the performance ofthrust and torque of the developed propeller was performed.
Several advantages of multihull, such as catamaran, have been extensively discussed in the previous research. Therefore, this research focuses on developing a catamaran hull form for the fish processing vessel hull. The initial stage is determining the principal dimension and exploring the configurations of catamaran hull forms. The existing high-speed craft catamarans have been adopted to determine the parent model main dimensions using a linear regression equation model. Otherwise, the catamarans single demi-hull geometry was developed by converting and modifying the parent model hull form with enlarging the hull displacement to achieve the deadweight capacity and service speed requirements. The demi-hull spacing configuration with s/L 0.17, s/L 0.20, s/L 0.30, and s/L 0.40 on the resistance characteristics, intact stability, and sea-keeping behaviour were also explored. Furthermore, the comparisons with the previously proposed monohull were presented. Regarding the hull resistance performance, the analysis indicated that the catamaran hull form had better total resistance characteristics than the monohull on the service speed over 23 knots. In the case of intact stability, the analysis results presented that the catamaran hull form has better intact stability characteristics than the monohull. The dynamic stability of the catamarans also gave better dynamic stability at the heeling angle below 41.57°. Otherwise, the catamarans with s/L 0.17 and s/L 0.20 have lower dynamic stability than the monohull at the heeling angle larger than 41.57° and 58.03°, respectively. In the sea-keeping performance, the catamaran hull has shown an excellent rolling motion required for the offshore environment loading/unloading process. The large demi hull spacing of the catamarans hull can reduce the effect of the wave creating load on the roll motion response at the Beam Sea.
Since roro passenger ships have specific characteristics in handling cargo with the roll-on-roll-off loading and unloading system that must be equipped with a ramp door. Therefore, it is important to conduct the ultimate strength analysis by considering local loads and global loads to ensure the level of safety and reliability of the ship structure. The aim of this research is focused on the investigation of the structural response and the ultimate strength of the roro passenger ship using the non-linear finite element method. The dynamic explicit method is conducted to estimate the large displacement of the deformed structures such as the hull girders, deck girders and plates. In the structural response analysis, the results shows that maximum stress was occurred on the deck girders due to the sagging bending moment load. In the ultimate strength analysis, it is identified that hydrostatic load have reduced the ultimate strength about 33 %. Otherwise, the ultimate strength is increased about 1 %, in the sagging condition.
HIGHLIGHTS
The nonlinear behavior of the roro passenger ship ultimate strength due to the combined global and local load is presented
On the hogging condition, the addition of local load (hydrostatic pressure) reduce the roro ship ultimate strength about 33 % compare to the pure global ultimate bending load
On the sagging condition, the hydrostatic pressure have slightly increased the ultimate strength around 1 %
GRAPHICAL ABSTRACT
Berdasarkan hasil observasi di lapangan dan diskusi dengan kelompok pengrajin flanel yang tergabung dalam UKM “Toko Ijo Asesoris” yang berlokasi di Bukit Kencana Jaya, Kelurahan Meteseh, Kecamatan Tembalang, Semarang mengakui adanya beberapa persoalan yang dihadapi dikalangan pengrajin flanel yaitu: terjadinya ketidakakuratan dalam proses pemotongan dengan menggunakan gunting, sehingga menyebabkan banyak bahan flanel yang terpaksa harus dibuang atau dimanfaatkan untuk sesuatu menurunkan nilai produk.Upaya peningkatan produktivitas melalui pengembangan dan penerapan alat potong kain mekanik untuk bentuk pola akan menjadi fokus penelitian ini. Penerapan alat potong mekanik diharapkan dapat meningkatkan kecepatan potong dan menurunkan kesalahan akibat pemotongan secara manual dengan menggunakan gunting khusunya bagi pengrajin pemula
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