Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean society of Fisheries Technology
Journal Basic Information
Journal DOI :
The Korean Society of Fisheries Technology
Editor in Chief :
Volume & Issues
Volume 19, Issue 2 - Jun 1983
Volume 19, Issue 1 - Mar 1983
Selecting the target year
The Behaviour of Shrimp , Palaeman Pacificus , to the Model Trap and the Odour of Baits
Ko, Kwan-Soh ; Kim, Yong-Hae ;
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 85~91
The behaviour of shrimp in response to the trap was much influenced by the type, size and the dimensions of entrance as well as physiological and ecological conditions. The entry and the escape behaviour of shrimp to the model trap were observed in accordance with netting materials, baits, type and slope of entrance, and gathering response were also investigated on the odour of bait extracts in the aquarium from June to August, 1983. Entering shrimp to the circular entrance was significantly more than to the triangular or the square; however, no differences were found in the entry behacior among netting materials i e., P. A, P. E. and cotton. According as the slope of entrance was increased its angle from 0
, number of entering shrimp was decreased; however, number of escaping shrimp at 30
with time was fewer than at 0
. Gathering responses of shrimp on the odours were more sensitive to the flesh of mackerel or the shrimp than to the pickled anchovy, or the pettitioes, while no differences were found between another bait extracts, i e., the shrimp and the flesh of mackerel, the short-necked clam and the horse mackerel, the flesh and the viscera of mackerel.
Effects of Ship`s Roll Motion on the Detectable Area of Echo Sounder
Park, Jung-Hee ; Sin, Hyeong-Il ; Lee, Dae-Jae ;
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 93~98
When detecting underwater targets using echo sounder, the echo signals varies with the angular displacement of the transducer due to ship's motion. Then, the effect of the angular which effects the capability of the echo sounder must be investigated in relation to the detection of fish concentration, particularly, the abundance estimation of fish. In this pater, as the basic research to investigate the effect of the ship's motion when estimating the fish stocks by acoustic methods, the authors was theoritically considered the variations in the values of the two way directivity function of transducer in the direction of the targets which caused by the angular motion of transducer. Here, the effects of the movement of target and ship's running are neglected. At the same time, the data was applied to estimate the angular shift of the detectable area of echo sounder due to transducer displacement. From the results analyzed, we found that the angular shift of the detectable area due to ship's motion increases both as the roll angle increases and as the beamwidth becomes narrower, varies with the depth.
A Study on the Relative Distance in Taking Action to Avoid Ship`s Collision
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 99~105
In the Steering and Sailing Rules of International Regulations for Preventing Collicions at Sea, 1972, any relative distance between two vessels necessary for taking action to avoid collision in head-on situation is not referred. In this paper, the author analyzed the ship's collision avoiding actions from a viewpoint of ship motions and worked out mathematical formulas to calculate the relative distances necessary for collision avoiding actions. Figuring out the values of maneuvering indices through experiments of actual ships, the author applied these values to the calculationg formulas and calculated the minimum safe relative distances. On the assumption that two vessels same in size and condition are approaching each other in head-on situation, the minimum safe relative distance was calculated as 5.0 times, sufficient safe relative one as 10.0 times their own length.
Variation of the Incident Sound Level at the Underwater Target`s Position due to Roll Motion of the Ship
Park, Jung-Hui ; Lee, Dae-Jae ;
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 106~110
As the first step to investigate the effect of ship's motion when detecting target with an echo sounder, variations in the incident sound level at the optional position within the sound beam due to roll motion of the transmitter have been measured and calculated. In this experiment, the transmitter (75 KHz) was mounted to the bottom of a FRP model of the 2,275 G. T. stern trawler and the receiver (75 KHz) was installed at each measuring point within the transmitter's beam. Then, the incident sound level was measured for the roll angles from the free roll test on the model ship. For a range of roll angle of
from the vertical, the measuring values of the incident sound level at each measuring point were rapidly fluctuated from 12.9% to 78.1 depending on the roll angle, and agreed well with the caculated ones. Consquently, we concluded that the effect of ship's motion when detecting target with an echo sounder should be sufficiently considered.
Helmholtz Coil and Performance of Magnetic Compass
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 111~116
In order to furnish the fundamental data for the domestic production of magnetic compass and the prescription of standardization about it in Korea, authors made the helmholtz coil and investigated the characteristics of them. Subsequently, the damping curves of T190 and T165 compasses in the helmholtz coil were measured and analyzed the performance of those compass. The results obtained are as follows; 1. The relation between electric current (I sub I) to flow in the helmholtz coils, that the thickness of coil is 1mm, diameter 1m, winding number 117, and intensity of magnetic field is presented as follows. Vertical magnetic force: Z(Gauss)=0.34+1.506 I sub(i) Horizontal magnetic force: H(Gauss)=0.183+1.506 I sub(i) 2. Period of T190 compass is longer than T165 compass in all horizontal magnetic force. In the amplitude, the former is larger than the latter above 0.08 Gauss, but this phenomenon is opposed to that below 0.08 Gauss. 3. As the porizontal magnetic force is intensive, period of magnetic compass is short, amplitude is large, and damping degree and damping factor are small. The time elapsed to the principal points of damping curve is proportional to the -0.65 power of the horizontal magnetic force.
Analysis on the Dynamic Respone of the Hull Structure due to Slamming Impact - By Finite Element Method -
Hong, Bong-Ki ; Moon, Duk-Hong ; Bae, Dong-Myung ;
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 117~124
In rough seas, actual behaviours of a ship may not be estimated by the linear strip theory, because of Nonlinearities due to the hull shape, bottom slamming and bottom and/or bow-flare slamming. In case of slamming, impulsive hydrodynamic pressure occurs on the fore body surface of the ship, resulting hull vibration called whipping, by which the ship may suffer from serious structural damages and the impact pressure, depends critically on the relative velocity at re-entry. In this paper, the Time history of impact froce at each station, the longitudinal distribution of impact force at critical time, the Time history of acceleration at F.P. and the Time history of Bending moment at midship are illustrated. That is, authors analyzed Dynamic response of container ship to be subjected slamming impact force.
Interaction Between the Viscous and Wavemaking Component Resistance
Kim, In-Chull ;
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 125~129
It is customary to assume that the resistance of a jull at uniform speed may be regarded as the sum of viscous and wavemaking component resistance, or C sub(i)=C sub(v)+C sub(w), where C sub(v) is regarded as a function of Reynolds Number R and C sub(w) a function of Froude Number F. Formulae have been obtained for ∂C sub(w)/∂R, ∂C sub(v)/∂F which may be relevant in seeking theoretical grounds for possible interaction between viscous and wavemaking component resistances. The values of ∂C sub(w)/∂R are small. In general they are smaller than corresponding values of ∂C sub(v)/∂R. But although these values are small it does not follow that they are entirely negligible. The Froude assumption that the rate of change of C sub(w) with R is zero must bel regarded as incorrect.
온산만 해역의 수질 조사 ( 2 ) ( Water Quality Survey on Onsan Bay ( 2 ) )
Yang, Byeong-Su ; Im, Jae-Myeong ; Kim, In-Su ;
Journal of the Korean society of Fisheries Technology , volume 19, issue 2, 1983, Pages 130~134