• Title/Summary/Keyword: Ship’s Speed

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A Study on the Ship's Speed for Reducing the Fuel Oil Consumption in Actual Ships (선박의 연료소모량 절감을 위한 항해 속력에 관한 연구)

  • Kim, Soon-Kap;Lee, Yun-Sok;Kong, Gil-Young;Kim, Jong-Pil;Jung, Chang-Hyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.18 no.1
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    • pp.41-47
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    • 2012
  • Recently, due to the rapid rise of the international oil price, the burden of fuel oil expense is relatively increasing in a ship. And the international restriction of the greenhouse gas which was generated from the burning of fuel oil is also rapidly strengthened. Therefore, to reduce the greenhouse gas and fuel oil consumption, many shipping company adopted the low speed navigation and it was focused on the improvement of fuel consumption efficiency and the usage of alternative energy in the marine engine development field. In this paper, the fuel oil consumption according to the ship's speed was measured in the actual seas and analyzed the shop test results in the shipyard and the ship navigation data from the abstract log. And then it was proposed that the ship's economic speed was 14~15kts and the optimum rpm was 140~150 in specific sea conditions.

A Case Study for Cabin Vibration Improvement of 432 ton class Car-ferry Ship changing Propeller Blade Number (프로펠러의 날개 수 변경에 의한 432톤급 카페리여객선 선실 진동 개선에 대한 사례 연구)

  • Yun, Hyunwoo;Dao, Vougang;Lee, Donchool
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.443-448
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    • 2014
  • Recently, car-ferry passenger ships of navigating the coast area in the inside of our country are on an increasing trend of main engine power and the height of upper structure, which is increased to ship's speed and loading of large vehicles. The most ship with high-speed main engine is happened to excessive vibration by propeller induced excitation force on account of connecting the vibration of hull's girder and the upper structure by decreasing the shear stiffness and natural frequency for increasing the height of passenger deck. In this paper, By exchanging the propeller of alteration the number of blades, it could be keep to ship's speed and it's decreased the vibration of hull part that is located passenger deck on the upper deck, which is identified by countermeasure of protection against vibration to procure the safety ship's navigation through measuring the vibration of hull structure.

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Stabilization of ship's heading in AIS of fishing vessel by a hybrid GPS/EM compass (어선 AIS에서의 하이브리드 GPS/EM 컴퍼스에 의한 선수방위 안정화)

  • Lee, Yoo-Won;Jo, Hyeon-Jeong;Lee, Dae-Jae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.46 no.1
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    • pp.50-55
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    • 2010
  • The ship's heading information of hybrid GPS/EM compass were applied to the AIS of fishing vessel and examined the possibility of accuracy improvement. It is observed 453 each in AIS receiver of land among 3,982 each in AIS Rx/Tx transponder of the test ship at sea, and transmission interval according to the speed of ship is determined the 11.4% good transmitting data of the all information. In results, maximum compass error for the ship's heading of an EM compass was $19.1^{\circ}$. The variance of ship's heading owing to the speed of ship is surveyed. The COG (Course Over Ground) was changed extremely in $180^{\circ}W-179^{\circ}E$ range under 4.9knots, and in $24^{\circ}W-23^{\circ}E$ range over 4.9knots. Finally, using the ship's heading of EM compass and the COG from GPS for the autopilot system of a small fishing boat and the ship's heading information of AIS results in danger on the own ship's navigation safety and leads to make confusion both the others and VTS (Vessel Traffic Service) center. Therefore, the hybrid GPS/EM compass is identified as the best system for a small fishing boat and is allowed to offer continuously a ship's heading information with high accuracy and stability.

A Study on Ship's Automatic Track-keeping Control considering disturbance effect (외란을 고려한 선박 자동 침로 제어 수치 시뮬레이션 연구)

  • Le, Thanh-Dat;Im, Nam-Kyun;Lee, Sang-Min
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2013.06a
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    • pp.17-20
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    • 2013
  • Many researches have been conducted in the field of constructing controllers for ships over 20 years. But still, ship automatic track-keeping controllers has not been designed for ship's automatic berthing as they considered nearly constant ship's speed. This study dealt with this problem to design track-keeping control on ship's model of SAE NURI using nonlinear mathematical expression. By using this control, the ship is auto track-kept in fare-way at reducing speed to anchorage place. The simulation results proved that this control can be adapted in ship's auto berthing in near future.

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Reduction of Fire Main Pipe System's Vibration Using Back Flow Prevent Globe Valve (역류방지 글로브 밸브를 이용한 소화 주관계의 진동개선)

  • Park, Mi-You;Han, Hyung-Suk;Lee, Seuk-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.518-523
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    • 2009
  • Main source of URN(Underwater Radiated Noise) which is related to the ship's survivability is divided into two groups. Cavitation is main source of URN when the speed of ship is upper than CIS(Cavitation Inception Speed). But when the speed of ship is lower than CIS, main source of URN is structure-borne noise on the hull which is originated from propulsion system, pump system or transmitted vibration of pipe system. In this paper, to reduce the vibration of discharge pipe and valve system, back flow prevent globe valve and new rubber mount are applied to the ship. As the result of applying new valve and mount, the vibration is reduced drastically.

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Reduction of Fire Main Pipe System's Vibration Using Back Flow Prevent Globe Valve (역류방지 글로브 밸브를 이용한 소화 주관계의 진동개선)

  • Park, Mi-You;Han, Hyung-Suk;Lee, Seuk-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.6
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    • pp.599-606
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    • 2009
  • Main source of URN(underwater radiated noise) which is related to the ship's survivability is divided into two groups. Cavitation is the main source of URN when the speed of ship is upper than CIS(cavitation inception speed). But when the speed of ship is lower than CIS, the main source of URN is the structure-borne noise on the hull which is originated from propulsion system, pump system and trnasmitted vibration of the pipe system. In this paper, to reduce the vibration of discharge pipe and valve system, back flow prevent globe valve and new rubber mount are applied to the ship. As the result of applying new valve and mount, the vibration is reduced drastically.

A Study on the Resistance Property of Hard Chine Type High Speed Planing Craft (HARD CHINE형 활주 고속선의 저항특성에 관한 고찰)

  • 이창억
    • Journal of the Korean Professional Engineers Association
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    • v.16 no.2
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    • pp.1-11
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    • 1983
  • The resistance property of a high speed passenger craft (: "DOL-PIN HO" designed by the author in 1972) is investigated as follows; -. The Resistance property of the craft is determined by savitsky′s method and blount-Fox′s method. The theoretical results are also compared with the full scale data. The comparison reveals that the result when using blount/fox′s method are in much closer agreement with the full scale data than savitsky′s. -. The effects of ship speed on the positions of the center of pressure and of the longitudinal center of gravity (L.C.G.) are investigated. The investigation shows that the position of L.C.G. of the craft is almost constant although the ship speed is changed. -. The effect of transom flap on the Resistance property of the craft is studied using savitsky/brown′s method. From the study it is found that the resistance of the craft is decreased and hence speed gain (about 3% of the service speed) can be obtained, when using transom flap for the craft.

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A method of inferring collision ratio based on maneuverability of own ship under critical collision conditions

  • You, Youngjun;Rhee, Key-Pyo;Ahn, Kyoungsoo
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.5 no.2
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    • pp.188-198
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    • 2013
  • In constructing a collision avoidance system, it is important to determine the time for starting collision avoidance maneuver. Many researchers have attempted to formulate various indices by applying a range of techniques. Among these indices, collision risk obtained by combining Distance to the Closest Point of Approach (DCPA) and Time to the Closest Point of Approach (TCPA) information with fuzzy theory is mostly used. However, the collision risk has a limit, in that membership functions of DCPA and TCPA are empirically determined. In addition, the collision risk is not able to consider several critical collision conditions where the target ship fails to take appropriate actions. It is therefore necessary to design a new concept based on logical approaches. In this paper, a collision ratio is proposed, which is the expected ratio of unavoidable paths to total paths under suitably characterized operation conditions. Total paths are determined by considering categories such as action space and methodology of avoidance. The International Regulations for Preventing Collisions at Sea (1972) and collision avoidance rules (2001) are considered to solve the slower ship's dilemma. Different methods which are based on a constant speed model and simulated speed model are used to calculate the relative positions between own ship and target ship. In the simulated speed model, fuzzy control is applied to determination of command rudder angle. At various encounter situations, the time histories of the collision ratio based on the simulated speed model are compared with those based on the constant speed model.

Hull From Development for a High Speed Container Ship (고속콘테이너선 선형개발)

  • S.I.,Hong;C.Y.,Kim;D.S.,Gong;S.I.,Yang;K.J.,Kang
    • Bulletin of the Society of Naval Architects of Korea
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    • v.27 no.3
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    • pp.1-10
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    • 1990
  • This paper represents the hull form development of a high speed container ship based on the thin ship theory, Hess & Smith method, the reference ship data and model test results. The high efficiency propeller designed by the lifting surface theory shows good performance in the cavitation and the pressure fluctuation force. Also, the optimum design technique based on the finite element method was adopted for the hull structure design and the hull vibration analysis. Finally, the performance of a newly developed container ship has been compared with the sea trial results and the excellent performance in speed, vibration, etc. was confirmed.

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A Study on the Techniques for Sailing Yacht Model Tests with Sailing Condition (항주자세를 고러한 세일링 요트의 선형기법 시험연구)

  • Sim, Sang-Mog;Kim, Dong-Joon;Kang, Byung-Yoon
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.1 s.145
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    • pp.32-42
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    • 2006
  • This study aims at establishing a technique for sailing yachts model tests with sailing condition. It is very important to estimate a ship's potential speed performance before building a real ship. Several methods are used to estimate a ship's potential speed performance such as using parent ship data, standard vessel chart and model test. Model test is the most precise among these options. In korea. model testing is widely used with general vessels but not with sailing yachts. Because sailing yachts are propelled with heeling and leeway. using the wind. another method is needed to estimate their speed. The new model test. which is different from tests for upright general vessels, is in a great demand. In this paper. we describe a test method for the sailing yacht model test. based on Masuyama's equation of motion. And we describe choosing scale ratio. production process and materials of the model. Also. various ways of measuring instruments. attaching jigs and adjusting calibration are described so that they can be utilized as useful data for model testing.