• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.359-362
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• 2006

This study develops an automatic berthing control algorithm for ships with a bow thruster and a stern thruster as well as a rudder. A nonlinear mathematical model for low speed maneuvering of ships is used to develop a MIMO(multi-input multi-output) nonlinear control algorithm. The algorithm consists of two parts, which are forward velocity control and heading angle control. The control algorithm is designed based on the longitudinal and yaw dynamic models of ships. The desired heading angle is obtained by the so called "Line of Sight" method. An optimal control force allocation method of the rudder and the thrusters is suggested. The nonlinear control algorithms are tested by numerical simulations using MATLAB, and shows good tracking performances.

• Journal of Ocean Engineering and Technology
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• v.22 no.3
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• pp.34-40
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• 2008

his study discusses the design of an automatic berthing control algorithm for ships with a haw thruster and a stern thruster, as well as a rudder. A nonlinear mathematical model for the law speed maneuvering of ships was used to design a MIMO (multi-input multi-output) nonlinear control algorithm. The algorithm consists of two parts, the forward velocity control and heading angle control. The control algorithm was designed based on the longitudinal and yaw dynamic models of ships. The desired heading angle was obtained by the so-called "Line of Sight" method. An optimal control force allocation method forthe rudder and the thrusters is suggested. The nonlinear control algorithm was tested by numerical simulations using MATLAB, and showed good tracking performance.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.597-602
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• 2008

T.S. HANBADA has a relatively large hull and superstructures above the water line, so she has much of leeway or turning of bow with the effect of winds. Especially on berthing, unberthing and/or sailing on low speed, these effects take place more significant. Therefore, it was carried out the numerical calculation of the wind force and moments acting on the T.S. HANBADA, and then calculated the leeway angle and counter rudder angle with the relative wind direction and velocity. Also, it was suggested the maximum wind velocity which could be berthed or unberthed used by bow thruster and the tugboat operations in strong winds. These results will be great helpful to the vessels with large superstructures on ship's handling in harbour or tugboat operations.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.277-282
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• 2006

The purpose in having a control surface on a ship is to control the motion of the ship. The control surface may be composed entirely of a single movable surface or of a combination of fixed and movable portion A control surface has one sole function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of this rotation and angle of attack then determine the maneuvering characteristics of the ship. In this paper the study of flapped rudder's 2-dimensional section was accomplished. Model tests had been carried out with different angles of attack of a main foil and flap's deflection angles to predict the performance of the flapped rudder and the 2 frame particle tracking method had been used to obtain the velocity distribution in the flow field $Re=2.8\times10^4$ had been used during the whole experiments and measured results had been compared with each other.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.66-72
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• 1994

For the reliable prediction of maneuverability of a ship, lots of captive model tests have been carried out for over 10 years. But the parameters appearing in the mathematical model are so versatile and showing complex characteristics, and it is still hard to establish the useful formulae that we can adopt directly in the design stage. In this paper, the most important parameters in the mathematical model. i.e.($1-\omega_P$) the effective wake fraction at propeller, and $\delta_R(\beta_R)$), the effective rudder inflow angles are investigated by the captive model tests at the circulating water channel. The model is tested at designed speed and at low speed, and the drafts at both full load and ballast load conditions are taken. Propeller thrusts and rudder normal forces are measured at the given drift angle and propeller revolution. These forces are used for the analysis of the effective flow velocity or flow direction, to the propeller or rudder.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.29-30
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• 2007

This paper deals with effect of wind forces and moment acting on the training ship SAE NUR/. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results am be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.145-153
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• 2002

A coastwise chemical tanker sailing at full speed has capsized in calm water and whole turing. In the precious paper, we investigated reasons of the accident by demonstrating the proper correction for the free surface effect of the liquid cargo and the bow-sinkage effect. In this paper, we also carry out model experiments of a transverse pressure under the seawater and an outward heel moment according to the heel angle and rudder angle, on the basis of radius of turning circle, ship's speed and drift angle of model ship occurring in turning. It is also shown that the flooding of seawater onto the deck occurring in turning generated a significant outward heel moment and the vertical distance between the center of gravity of the ship and the renter of lateral water drag.

• Journal of Navigation and Port Research
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• v.32 no.2
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• pp.115-120
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• 2008

This paper deals with effect of wind forces and moment acting on the training ship SAE NURI. The results of drift angle and counter rudder angle due to wind effect are calculated by using the static equilibrium method especially with nonlinear mathematical expression, and then the critical wind velocity is found out. The given results can be applied directly to T/S SAE NURI in handling under the wind condition and used for merchant ships as a referential tool.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.2
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• pp.177-186
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• 2017

This study is intended to provide navigator with specific information necessary to assist in the avoidance of collision and in operation of ships to evaluate the maneuverability of research vessel Jera. Authors carried out full-scale sea trials for turning test, zig-zag test, and spiral test at actual sea-going condition, which were performed on starboard and port sides with 10-20 rudder angle at service speed of 10 knots. The turning circle was much different at both of the turning of port and starboard which was longer at the starboard than at the port. In the zig-zag test results, the port and starboard was $10^{\circ}$ the first and second overshoot angles were $6.0^{\circ}$, $5.8^{\circ}$ and $6.3^{\circ}$, $7.1^{\circ}$ respectively and the first overshoot angles were $16.4^{\circ}$, $17.6^{\circ}$ when using $20^{\circ}$. Her maneuverability index T and N can be easily determined by using an analogue computer with the data obtained from the zig-zag tests where K is a constant representing the turning ability and T is a constant representing her quick response. In the zig-zag tests under $10^{\circ}$ or $20^{\circ}$ at rudder angle, the value K is 0.149. 0.123 sec- and T is 11.853 and 6.193 sec and angular velocity is $0.937^{\circ}/sec$ and $1.636^{\circ}/sec$. In the spiral test, the loop width was unstable at $+0.51^{\circ}$ and $-1.19^{\circ}$ around the midship of rudder, but the tangent line at $0^{\circ}$ was close to vertical. From the sea trial results, we found that she did comply with the present criterion in the standards of maneuverability of IMO.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.84-92
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• 1995

The methods by turning circle test and maneuvering indices have been used to study and evaluate the maneuverability of a ship. However recently many studies utilizing the GPS are made on the measurement of the turning circle and in the fishery and hydrographic survey. In this paper, the author carried out the turning circle test using the differential GPS and dumb card together, and compared the data measured by them and analyzed the accuracies of them to obtain the utility basic ones on the measurement of the turning circle by the DGPS. The main results area s follows : 1) To check the accuracies of the GPS, the circling experiments of 50m radius by the DGPS were made on the ground. The accuracies of turning circle measured by the DGPS were found to be very high as the errors of 1.5m. 2) the turning circle by the DGPS could be measured very accurately, by the seed, rudder angle, starboard and port respectively. 3) The turning circle measured by the dumb card was found to be measured accurately as much as the DGPS, when using large rudder angle, the turning circle was large, the turning circle by the dumb car could not be measured accurately on account of large error of bearing of compass. 4) The tactical diameters by the DGPS in case of the rudder angle 35。~5。, were found to be 2.6。15.0 times the Lpp of S.T HAELIM-3 at her slow speed 2.8~16.6 times her Lpp at her half speed, 3.1~17.4 times her Lpp at her full speed. The tactical diameter by the dumb card was found to be 2.4~9.5 times, 2.6~9.6 times, 3.2~12.2 times her Lpp respectively, in the above case and speed.