• Title/Summary/Keyword: Crabbing test

Search Result 5, Processing Time 0.021 seconds

On the Crabbing Tests of Cruise Vessel Equipped with Bow Thrusters and POD System (Bow Thruster가 있는 POD 추진 크루즈선의 Crabbing 시험)

  • Yeo, Dong-Jin
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.49 no.4
    • /
    • pp.327-332
    • /
    • 2012
  • International Towing Tank Conference (ITTC) recommended verifying a ship's ability to move transversely at zero forward speed without altering heading by a crabbing test. In sea trial, all available propellers/rudders/thrusters should be used to find the maximum possible transverse speed. For estimating crabbing ability in the design stage, tests to estimate possible swaying force and yawing moment range using all available propellers/rudders/thrusters are conducted. By butterfly diagram, which compares possible swaying force and yawing moment range with external swaying force and yawing moment by wind, a ship's crabbing ability can be estimated. In this study, model tests of a cruise vessel equipped with bow thrusters and POD system were conducted to find out her crabbing ability in the design stage. To mimic quay condition, a model quay-wall was set in the towing tank.

Crabbing Test of a 3m Ferry Model (3m Ferry 모형선의 Crabbing 시험)

  • 신현경;이형락
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.41 no.1
    • /
    • pp.40-46
    • /
    • 2004
  • In this paper, one of the harbour manoeuvring tests is described. its goal is to investigate the so-called crabbing performance of ships. By crabbing is meant the ability of the vessel to move sideways with the use of her own manoeuvring devices like propellers, rudders, transverse thruster, etc. The crabbing model tests were carried out in the Ocean Engineering Wide Tank, University of Ulsan(UOU) to measure the transverse forces and yawing moments by the transverse thruster alone and the propeller-rudder arrangement in combination with the bow thruster. The comparison between UOU crabbing test results and data measured at one of foreign research institutes showed a little gap due to different rotating conditions of controllable pitch propellers.

A Study on Full-Scale Crabbing Test Using Dynamic Positioning System (동적위치제어시스템을 이용한 선박의 실선스케일 횡이동시험에 관한 연구)

  • Park, Jong-Yong;Lee, Jun-Ho
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.57 no.6
    • /
    • pp.345-352
    • /
    • 2020
  • This study aims to investigate the crabbing motion of the research vessel "NARA" by full-scale maneuvering trials. The crabbing test method refers to ITTC recommended procedures and guidelines. In order to minimize the fluctuation of the heading angle due to the external force acting on the hull during the pure lateral motion, the tests are conducted using the dynamic positioning system applied to the ship. The test results are analyzed by applying a low-pass filter to remove the noise included in the measurement data. Three conditions are set to define the steady state of crabbing motion. The index to be derived from the crabbing test is quantitatively presented. The ship is confirmed to be capable of the lateral motion of up to 0.844m/s in Beaufort 3.

Crabbing Test of a 3m Ferry Model (II) (3m Ferry 모형선의 Crabbing 시험(II))

  • SHIN HYUN KYOUNG;LEE HYUNG LAK
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • 2004.05a
    • /
    • pp.290-297
    • /
    • 2004
  • In this paper, one of the harbour maneuvering tests is described. Its goal is to investigate the so-called crabbing performance of ships. By crabbing is meant the ability of the vessel to move sideways with the use of her own maneuvering devices like propellers, rudders, transverse thruster, etc. the 3m ferry model is made by ocean engineering wide tank in the university of ulsan. when the model ship is leaving and going to the quay, Transverse forces and Yawing moments are measured, in the condition of zero longitudinal force and the design draught, by load cell attached to the longitudinal center of gravity on the ship. the purpose of the experiment is to verify the reliability of ocean wide tank in university of ulsan about crabbing test compared with results of foreign research institute.

  • PDF

Crabbing Motion Testing of Waterjet-Powered Ships Using Stern Thrusters

  • Joopil Lee;Seung-Ho Ham
    • Journal of Ocean Engineering and Technology
    • /
    • v.38 no.1
    • /
    • pp.10-17
    • /
    • 2024
  • This study assessed the potential for crabbing motion in waterjet ships by exclusively employing stern thrusters. The theoretical considerations were validated through practical sea trials on the naval vessel PKG (Patrol Killer Guided missile) equipped with three stern thrusters. The control forces were calculated using the force equilibrium equation. The results showed that the hull exhibited rotations and lateral movements under wind influence. The port tail exhibited a leftward turning tendency due to the wind. This phenomenon arises from the dominance of the rotational force generated by the stern thruster over the lateral force exerted by the hull, making it challenging to maintain force equilibrium. In the sea trial, the hull rotated by 10° and moved 10.8 m laterally, with a longitudinal movement of 0.26 m. Remarkably, the lateral movement surpassed the longitudinal displacement, indicating the success of the trial. The substantial lateral travel distance provided tangible evidence that the crabbing motion of the ship is achievable using only stern thrusters. This study contributes valuable insights into enhancing the maneuverability of waterjet ships, offering practical applications for naval operations and maritime activities.