A Study on Motion Response of Small Fishing Vessels According to Various Tonnage in Regular Waves

2021 ◽  
Vol 27 (6) ◽  
pp. 832-838
Author(s):  
Nam-Kyun Im ◽  
◽  
Sang-Min Lee
Keyword(s):  
Regular Waves ◽  
Motion Response ◽  
Fishing Vessels

The Transverse Plane Motions of Ships

1991 ◽  
Vol 28 (02) ◽  
pp. 55-72
Author(s):  
Bruce L. Hutchison
Keyword(s):  
Transverse Plane ◽  
Irregular Waves ◽  
Hydrodynamic Coefficients ◽  
Important Process ◽  
Regular Waves ◽  
Hull Form ◽  
Fishing Vessels ◽  
Transverse Stability ◽  
Roll Axis ◽  
The One

A detailed exposition of the kinematics of the transverse plane motions of ships is provided, with particular attention to the important process of total transverse acceleration in vessel coordinates. The loci of sway, sway velocity and sway acceleration are shown to follow hyperbolic distributions with respect to elevation in both regular and irregular waves. In regular waves the transverse acceleration in earth-fixed and vessel-fixed coordinates are shown to be congruent with a vertical shift in elevation of g/ω2 = λ/(2π). Expressions are given for the elevations minimizing transverse plane processes in regular and irregular waves. In long waves the elevation minimizing total transverse acceleration in vessel coordinates is shown to be g/ωn2 = g[Tn/ /(2π)]2 below the waterline. This is the roll center, which should be used in the traditional analysis of foundation loads. Its location, far below the keel for most vessels, is surprising. The elevation (OP) of the roll axis, which must be used when solving the one-degree-of-freedom equation for roll, is given and is shown to require hydrodynamic coefficients for sway as well as roll. In general, OP does not correspond to an elevation that minimizes any of the transverse plane processes. The effect of hull form, transverse stability and natural roll period on transverse plane motions are examined in an attempt to resolve the dichotomy of views between those who favor ships with low GMT and long natural roll periods and those who favor high GMT with short natural roll periods. It is demonstrated that large values of the beam-to-draft ratio (6/7) with low natural roll periods are advantageous at modest elevations above the waterline. This explains the favorable offshore experience in vessels meeting this description, such as tugs, supply vessels and fishing vessels. At higher elevations long natural periods are shown to present a clear advantage, which supports the preference for low GMT for large passenger vessels, containerships and ships with deck-loads of logs. The trends identified would seem to support the conjecture that, with regard to natural roll period, there is a "forbidden middle" that should be avoided in design.

Modal Test for Response Amplitude Operator of a Deepwater Semi-Submersible Platform

2014 ◽  
Vol 945-949 ◽  
pp. 725-729 ◽  
Author(s):  
Li Ping Sun ◽  
Shu Long Cai ◽  
Zhuang Kang
Keyword(s):  
Model Test ◽  
Oil And Gas ◽  
Numerical Results ◽  
Response Amplitude ◽  
Dynamic Responses ◽  
Experimental Measurements ◽  
Regular Waves ◽  
Motion Response ◽  
Modal Test ◽  
Response Amplitude Operators

Semi-submersible plays an important role in ocean oil and gas exploitation. This paper carried out a model test for motion response of a deepwater semi-submersible in regular waves with the model oriented in the head, beam and quartering directions. The results were presented as Response Amplitude Operators (RAO) of the platform. Dynamic responses measured in the model test were compared with the numerical results obtained by the software HYDROSTAR. Results show that the numerical results generally tally well with the experimental measurements. This illustrates the accuracy of the numerical results, and proves that the numerical results are reliable to be the reference of judging performance of the platform.

scholarly journals Dynamic Behavior of a Flexible Multi-Column FOWT in Regular Waves

2021 ◽  
Vol 9 (2) ◽  
pp. 124
Author(s):  
Taisuke Takata ◽  
Mayuko Takaoka ◽  
Rodolfo T. Gonçalves ◽  
Hidetaka Houtani ◽  
Yasuo Yoshimura ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Elastic Deformation ◽  
Wave Spectrum ◽  
Elastic Response ◽  
Elastic Behavior ◽  
Design Stage ◽  
Offshore Wind Turbine ◽  
Regular Waves ◽  
Vibration Period ◽  
Motion Response

A tank experiment using a flexible multi-column floating offshore wind turbine (FOWT) model in regular waves was carried out to clarify the floater elastic response and its influence on the floater motion. The model motion response from the experiment was compared with the numerical simulations by NK-UTWind and WAMIT codes. The dynamic elastic deformation of the model was also compared between the experiment and NK-UTWind. The experiment observed significant elastic deformation for the decks and columns of the model around the wave period corresponding to the natural period of the structural vibration. Furthermore, comparing the heave response amplitude operator (RAO) between experiments and numerical simulations, a small peak appeared around this period in the experiment and NK-UTWind simulation instead of WAMIT simulation. These results indicated that dynamic elastic deformation affected the heave response of the model. The change in the model rigidity revealed that such elastic deformation could affect the motion response statistics in an actual sea condition if the peak period of the onsite wave spectrum is close to the floater natural vibration period. These investigations indicated the importance of considering the elastic behavior of a FOWT at its design stage.

Motion response of floating structures to regular waves

1980 ◽  
Vol 2 (3) ◽  
pp. 99-106 ◽  
Author(s):  
B.J. Natvig ◽  
J.W. Pendered
Keyword(s):  
Regular Waves ◽  
Floating Structures ◽  
Motion Response

Quality of Services Publishing Record of Fisheries (BPKP) in The Marine and Fisheries Office South Sumatera Province

2018 ◽  
Vol 1 (2) ◽  
pp. 25-32
Author(s):  
Galamda Israk ◽  
Slamet Widodo ◽  
Andy Alfatih
Keyword(s):  
Quality Of Service ◽  
Data Collection ◽  
Service Quality ◽  
Participant Observation ◽  
Secondary Data ◽  
Likert Scale ◽  
Quality Of Services ◽  
Fishing Vessels ◽  
Scale Assessment

ABSTRACT This study aims to determine the quality of service issuance of Proof of Registration of Fishing Vessels (BPKP) in the Department of Maritime Affairs and Fisheries of South Sumatra Province and what factors influence it. Data collection techniques used were the distribution of questionnaires to 60 respondents who were capture fisheries business actors with a Likert Scale assessment, as well as conducting unstructured interviews, non-participant observation and secondary data collection. The dimensions used are tangible, reliability, responsiveness, assurance and empathy. The value of service quality based on tangible dimensions is 4.2 or good, based on the reliability dimension is 4.1 or good, the responsiveness dimension is 4.0 or good, the guarantee dimension is 4.1 or good, and based on the empathy dimension is 4.1 or good. Of all these parameters, it was concluded that the quality of BPKP issuance services in the Department of Maritime Affairs and Fisheries of South Sumatra Province in 2016 was good with a score of 4.1. The conclusion is based on an assessment of an average of 58 respondents or 97.4% of respondents.

scholarly journals Fisheries: A Missing Link in Greenhouse Gas Emission Policies in South Korea

2021 ◽  
Vol 13 (11) ◽  
pp. 5858
Author(s):  
Kyumin Kim ◽  
Do-Hoon Kim ◽  
Yeonghye Kim
Keyword(s):  
Greenhouse Gas ◽  
Greenhouse Gas Emission ◽  
Ghg Emissions ◽  
Bioeconomic Model ◽  
Negative Externalities ◽  
Fishing Vessel ◽  
Gas Emission ◽  
Fishing Vessels ◽  
The Government ◽  
Different Levels

Recent studies demonstrate that fisheries are massive contributors to global greenhouse gas (GHG) emissions. The average Korean fishing vessel is old, fuel-inefficient, and creates a large volume of emissions. Yet, there is little research on how to address the GHG emissions in Korean fisheries. This study estimated the change in GHG emissions and emission costs at different levels of fishing operations using a steady-state bioeconomic model based on the case of the Anchovy Tow Net Fishery (ATNF) and the Large Purse Seine Fishery (LPSF). We conclude that reducing the fishing efforts of the ATNF and LPSF by 37% and 8% respectively would not only eliminate negative externalities on the anchovy and mackerel stock respectively, but also mitigate emissions and emission costs in the fishing industry. To limit emissions, we propose that the Korean government reduce fishing efforts through a vessel-buyback program and set an annual catch limit. Alternatively, the government should provide loans for modernizing old fishing vessels or a subsidy for installing emission abatement equipment to reduce the excessive emissions from Korean fisheries.

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