• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.61-70
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• 2015

In an attempt to improve the maneuvering character of hull form renovated tuna purse seiner. A renovation was carried out on the 3 tuna purse seiner fishing vessel. To grasp the progress of maneuvering and resistance on ship B (730 ton class), new bulbous bow was only attached. The ship A (740 ton class) and C (600 ton class) were modified for new bulbous bow, enlarged slipway and rudder. And then the zigzag and the turning test were carried out. According to the turning test, the advance and the tactical diameter were improved very much for the modified ship. The sea trial was carried out for the original and modified ship A. It is showed that the results of sea trial corresponded with that of the tank test on the whole. In the result of the zigzag test on ship B, the turning ability was improved very much, but the yaw checking ability was deteriorated in just some degree. In the result of the zigzag test on ship C, the turning ability and yaw checking ability were remarkably improved. Ship C was greatly improved among the three ships for the maneuvering character of modified hull form.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.112-118
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• 2013

This paper reports the results of a comparative study on rudder performance between the steel rudders that have been used in coastal angling fishing boats in the 20-GT class and the newly developed FRP composite material rudders. In order to compare the rudder performances of these two types, a sea trial test was carried out to investigate the speed performance, fuel consumption, and ship's turning ability. The results showed that the sea trial performance of the FRP composite rudder was better than that of the steel rudder type in terms of the sea speed, fuel consumption rate, and turning ability.

• Journal of Navigation and Port Research
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• v.33 no.9
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• pp.623-628
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• 2009

The objective of this paper is to make clear the difference of maneuvering characteristics of a VLCC in standstill from those of her in running. The authors made mathematic models to calculate maneuvering motions of a VLCC in standstill using various ahead engine with full rudder angle and calculated their motions in each case and compared the calculated values with those of the same vessel running in sea trial tests. The difference of motions between them is great. For example, a VLCC in standstill can achieve a great alteration of heading over 90 degrees within the distance of 0.2L advance while she advances 3.0L for 90 degrees turning in full running sea trial turning test. Therefore whenever a VLCC in standstill meets a vessel approaching in collision course situation in near distance, it is better and recommendable that she should use her ahead engine with full rudder to avoid collision. So "maneuvering trial tests in standstill conditions" should be added to the content of sea trial tests when a newly built VLCC commence to take sea trials, that has not been included until now.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.623-630
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• 2013

This study was to evaluate hydrodynamic performance evaluation between an abroad product, a developed inflatable kayak and new developed kayaks. In order to test, inclining and turning trial test were carried out in the Ocean engineering Basin. Also, resistance test was carried out using a reduced scale model in the circulating water channel. In conclusion, stability of KONA was evaluated was the most greatest, the coefficient of resistance and center of gravity from RD-FK-12 were considerable, and turning performance of RD-FK-11 was greater than this of KONA and RD-FK-12.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.5
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• pp.627-634
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• 2012

This study includes results of basin test for hydrodynamic performance evaluation with a developed inflatable kayak. Inclining experiment and turning trial experiment of the developed inflatable kayak and an abroad product were carried out in the Ocean engineering Basin. Resistance test was carried out by using downscale model in the circulating water channel. Through method of following performance evaluation, advantage and disadvantage of the developed inflatable kayak were compared with those of the abroad product.

• Journal of Ship and Ocean Technology
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• v.3 no.3
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• pp.25-44
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• 1999

Estimation efficiencies according to different sea trial are investigated in connection with sensitivity analysis, and new trial method is proposed which can improve the estimation efficiency of hydrodynamic derivatives. MMG Equation with Kijima's formula is used for simulation. Extended Kalman Filter is chosen for estimation technique and hydrodynamic derivatives of interest is limited to 12 of those in sway and yaw equations. Esso Osaka is selected for the test ship. Sensitivity analysis and estimation results based on conventional trials show that a more sensitive derivative gives more efficient estimation result. Sensitivities of nonlinear derivatives become pronounced in the trial where steady condition lasts longer such as turning test, while sensitivities of linear derivatives gas a larger values in the trial where unsteady condition lasts longer such as 10deg-10deg zigzag test. Consequently, in new method , named S-type trial, steady and unsteady condition are combined appropriately to increase sensitivities. Linear derivatives are estimated better in S-type trial and the estimation of nonlinear derivatives is improved to extent.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.334-341
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• 2015

This study is to evaluate hydrodynamic performance evaluation between three kinds of inflatable kayaks, that is, a frame kayak, a needle knife kayak, and a v-hull kayak. In order to test, inclining and turning trial test are performed in the Ocean Engineering Basin. Also, a resistance test is performed with a reduced scale kayak in the circulating water channel. Consequently, First, the moment arm of a v-hull kayak is the largest with 132.4mm, but turning radius of one was the smallest of them. Second, the resistance of a needle knife kayak is the smallest with 71N, the center of gravity of one was the lowest with 0.128m of them, and then needle knife kayak occurs in a draft overall. Consequently, the v-hull kayak has had the advantages on restoring force and turning performance than others. The needle knife kayak has been more excellent on resistance and center of gravity than others.

• Journal of Navigation and Port Research
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• v.36 no.1
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• pp.15-20
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• 2012

In order to investigate the maneuverability of tug-barge, sea trial tests such as speed, acceleration/deceleration, $10^{\circ}$ turning, $20^{\circ}$ turning, $10^{\circ}/10^{\circ}$ zigzag and $20^{\circ}/20^{\circ}$ zigzag were conducted with both tug and tug-barge. From the result of turning test, longer tactical diameter and lower rate of turn of tug-barge than those of tug are obtained. From the result of the zigzag test, bigger overshoot angle of tug-barge than that of tug is obtained. When they turned or changed a course, it showed that the barge turned inner side of the trajectory of tug. For the safe navigation, the helmsman of tug-barge should be aware of these maneuvering characteristics.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.1
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• pp.8-14
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• 2011

RIB(Rigid Inflatable Boat) is widely used for coastal transportation in the commercial use and for ISR(Intelligence, Surveillance, Reconnaissance) in the military use. Since RIB is around 10 meters in length and over 30 knots in speed, its motion characteristics in waves is quite different from a large scale ship. When it turns, large roll occurs and heeling direction is opposite to the large ship's case. Currently, many countries are developing USV(Unmanned Surface Vehicle) of which type is RIB. In order to develop high performance autopilot and way point controller, it is very important to identify RIB's motion characteristics. In this paper, sea trial test results of a 7-meter RIB such as speed, turning, zig-zag, and way point control tests were represented and its resistance and propulsion model was identified by using sea trial data and Savitsky's formula. In addition, the state space model which will be used in the identification of the four-degree-of-freedom dynamics in the next step was formulated and the identification procedure was proposed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.4
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• pp.275-284
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• 2001

The for this study, turning circle tests and maneuvering indices were conducted to study and evaluate the maneuverabilities of the fishery training ship M.S. A-RA(G/T : 990tons). The results obtained were summarized as follows : 1. The advances of the starboard and port of the turning circle were measured based on the dumb card test method were 198m, 192m, the size of tactical diameters of them were 194m, 188m, respectively. 2. The advances at the starboard and port of the turning circles were measured according to the DGPS positioning obtained 196m, 194m, the size of tactical diameters of them were 194m, 190m, respectively. 3. The results were compared which came from the sizes of turning circle measured up with the dumb card test method during the trial test and from the size of turning circle measured according to the DGPS positioning. The advance of the turning circle measured at the time of the starboard turning according to the DGPS positioning was 1m longer than that of the trial test. And it was 21m shorter at the time of the port turning. 4. The rudder was steered at $35^{\circ}$ of rudder angle each starboard and port while the ship M.S. A-RA was advancing at full speed of 13 k't. The velocity of the ship was reduced to 7.8 k't at $180^{\circ}$ of turning angle and 6.0 k't at $360^{\circ}$ of turning angle and mean values of turning angular velocity of the port and starboard were $2.4^{\circ}$/sec and $2.3^{\circ}$/sec, respectively. 5. The Z test at each $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$ of rudder angle was carried out to have the maneuvering indices K and T measured. K for the each rudder angle were 1.24, 1.45, and 1.65 while T for the each rudder angle were 0.33, 0.20, and 0.14. That is, K at the Z test at $30^{\circ}$ was greater than at the Z test of $10^{\circ}$ and $20^{\circ}$ while T at the $30^{\circ}$ Z test was less than at the Z test of $10^{\circ}$ and 20.