Net winch design in trawlers, influence of vessel size and fishing ground

Author(s):  
Luis Carral Couce ◽  
Juan Carral Couce ◽  
Javier Tarrío-Saavedra ◽  
José A Fraguela Formoso

With mid-depth trawling techniques, the number of fishing grounds available increases. In turn, the vessel can have a greater workload, as it has to control and direct its activity towards different species depending on the use of mid- or deep-sea equipment. However, specific equipment for each depth has to be used and this equipment influences the fishing manoeuvre. A new piece of auxiliary equipment comes into play to haul and store the net: the net winch. The aim of this study is to determine the most suitable net winch for each of the various vessels, fishing grounds and fishing modalities of the Spanish trawling fishing fleet. For each fishing ground, vessel size and target species, a relationship will be established with the net winch design parameters: fishing reel capacity, traction and operation speed.

2021 ◽  
Author(s):  
Nitin D. Pagar ◽  
Amit R. Patil

Abstract Exhaust expansion joints, also known as compensators, are found in a variety of applications such as gas turbine exhaust pipes, generators, marine propulsion systems, OEM engines, power units, and auxiliary equipment. The motion compensators employed must have accomplished the maximum expansion-contraction cycle life while imposing the least amount of stress. Discrepancies in the selecting of bellows expansion joint design parameters are corrected by evaluating stress-based fatigue life, which is challenging owing to the complicated form of convolutions. Meridional and circumferential convolution stress equations that influencing fatigue cycles are evaluated and verified with FEA. Fractional factorial Taguchi L25 matrix is used for finding the optimal configurations. The discrete design parameters for the selection of the suitable configuration of the compensators are analysed with the help of the MADM decision making techniques. The multi-response optimization methods GRA, AHP, and TOPSIS are used to determine the parametric selection on a priority basis. It is seen that weighing distribution among the responses plays an important role in these methods and GRA method integrated with principal components shows best optimal configurations. Multiple regression technique applied to these methods also shows that PCA-GRA gives better alternate solutions for the designer unlike the AHP and TOPSIS method. However, higher ranked Taguchi run obtained in these methods may enhance the suitable selection of different design configurations. Obtained PCA-GRG values by Taguchi, Regression and DOE are well matched and verified for the all alternate solutions. Further, it also shows that stress based fatigue cycles obtained in this analysis for the L25 run indicates the range varying from 1.13 × 104 cycles to 9.08 × 105 cycles, which is within 106 cycles. This work will assist the design engineer for selecting the discrete parameters of stiff compensators utilized in power plant thermal appliances.


Author(s):  
Beatriz Susana Beltrán León ◽  
Raúl Ríos Herrera ◽  
Efraín Rubio Rincón

We present new records of larvae and adult fish from the family Callionymidae in the Colombian Pacific coast. Larvae and juvenile of Synchiropus atrilabiatus (Garman 1899), expands its distribution range within this coast (between Tumaco in the South to the border with Panama in the North), presenting low to medium abundances in September-October 2002, 2003, 2004, 2005 and February-March 2006, 2014. Larvae were always collected at stations 54 km away from the coast. Adults of S. atrilabiatus were collected as bycatch from the deep-sea shrimp fishing fleet between 67-700 m depth at Bahía Cupica in 1995 and Arusí in 2005.


Author(s):  
Behnam Ghalamchi ◽  
Adam Kłodowski ◽  
Jussi T. Sopanen ◽  
Aki M. Mikkola

The main scope of this paper is optimization of high speed rotor systems by using Evolutionary Algorithm. The target of the optimization is finding geometrical parameters of the shaft, in such a way that the critical speeds are not occurring in the operation speed range. Rotating machines have a wide range of applications in industrial machinery and applying numerical optimization techniques helps engineers to improve the performance of rotor bearing systems. A schematic of a turbine rotor system is studied. The rotor is modeled using finite element method and Timoshenko beam elements having four degrees of freedom (DOF) per node — two translational and two rotational. Critical speeds are identified using Campbell diagram. The outcome of the simulation is looking to find the widest safe margin for operation speed range without any critical speed in Campbell diagram within the operation range. Design parameters for optimization are overhang shafts lengths and diameters. Several simulation runs with different variables shows a significant effect of these parameters in dynamic behavior of the system. Comparison of the results with the basic design of turbine rotor reveals that all constraints are satisfied.


2021 ◽  
Vol 276 ◽  
pp. 01022
Author(s):  
Liu Xiaohui ◽  
Qin Shengjie ◽  
Yang Lei ◽  
Qi Haibin ◽  
Zhang Qi

The South China Sea is the sea area with the largest area, the largest depth, the most abundant oil and gas resources and the most comprehensive biological species in China. The further exploration of the South China Sea with manned submersible and other major deep-sea equipment is of great significance to China's deep-sea scientific investigation. In this paper, Jiaolong manned submersible was taken as an example. In order to explore the operation window to guarantee the operation safety of manned submersible and improve the efficiency of voyage scientific investigation, this paper combined the global wave return data and the wave data based on satellite remote sensing to focus on the Marine environment characteristics in the South China Sea. According to the operational design parameters of Jiaolong, in the South China Sea, the most appropriate operating time window is from April to September, and the rest of the time, proper sea conditions should be selected for the operation.


2017 ◽  
Vol 9 (1) ◽  
pp. 337-356
Author(s):  
Andi Alamsyah Rivai ◽  
Vincentius P. Siregar ◽  
Syamsul B. Agus ◽  
Hiroki Yasuma

Information on the spatial and temporal of fishing activity can optimize a fisheries management and increase their economical and biological benefit. For effective management and good understanding of fishing activities, information about fishing ground is crucial. In this study, we aimed to analyze the spatio-temporal of lift net fisheries in Kepulauan Seribu by analyzing their fishing season, investigating their hotspot of fishing ground using GIS-based hotspot model, and mapping the potential fishing ground of each target species. We found that anchovy and scad could be caught throughtout the year, while sardine and squid had high fishing season in west monsoon. Hotspot of fishing ground of lift net fisheries in Kepulauan Seribu waters generally was concentrated around Lancang Island and in southern part of Kotok Island. Potential fishing ground for sardines was located in around Lancang Island on west monsoon. Squids were highly distributed around Lancang Island in December to January and around Lancang and Rambut Islands in November. Anchovy and scad had more potential fishing ground in around Kepulauan Seribu waters.  Keywords: fishing ground, lift net, hotspot, fishing season 


Author(s):  
Zhufeng Shao ◽  
Haisheng Li ◽  
Liping Wang ◽  
Zhaokun Zhang ◽  
Rui Yao ◽  
...  

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