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Pui W Kong - One of the best experts on this subject based on the ideXlab platform.

  • stroke characteristics in sprint kayaking how does seat order influence synchronization in a k2 Crew Boat
    Journal of Mechanics in Medicine and Biology, 2020
    Co-Authors: Pui W Kong
    Abstract:

    The purpose of this study was to investigate the how seat order in a two-seater (K2) Crew Boat could influence the performance time and stroke synchronization during high intensity sprint kayaking....

  • STROKE CHARACTERISTICS IN SPRINT KAYAKING — HOW DOES SEAT ORDER INFLUENCE SYNCHRONIZATION IN A K2 Crew Boat?
    Journal of Mechanics in Medicine and Biology, 2020
    Co-Authors: Pui W Kong
    Abstract:

    The purpose of this study was to investigate the how seat order in a two-seater (K2) Crew Boat could influence the performance time and stroke synchronization during high intensity sprint kayaking. Sixteen national team sprint kayakers formed eight K2 Crews based on preference. Each Crew performed two 200[Formula: see text]m segments at high intensity in their preferred order (e.g., Paddler A in front, Paddler B behind), and then the reversed order (i.e., Paddler B in front, Paddler A behind). Video analysis identified stroke synchronization based on a four-position model. Magnitude-based inferences were used for statistical analysis. The preferred seat order was [Formula: see text][Formula: see text]s faster than the reversed seat order but the effect was possibly trivial. As four Crews were faster in the reversed seat order, data were also rearranged to compare between the slower and faster trials. The faster trials were [Formula: see text][Formula: see text]s quicker than the slower trials, which was a very likely effect. There was no clear effect of seat order on stroke synchronization between the two paddlers. Since faster timing does not always correspond with the preferred sear order, sprint kayak athletes are recommended to try both possible seat orders in a K2 Crew Boat rather than relying on preference alone.

  • a video based method to quantify stroke synchronisation in Crew Boat sprint kayaking
    Journal of Human Kinetics, 2018
    Co-Authors: Pui W Kong
    Abstract:

    : The study aimed to quantify stroke synchronisation in two-seater Crew Boat sprint kayaking (K2) using a video-based method, and to assess the intra- and inter-rater reliabilities of this method. Twelve sub-elite sprint kayakers (six males and six females) from a national team were paired into six single-gender K2 Crews. The Crews were recorded at 120 Hz with a sagittal-view video camera during 200-m time trials. Video analysis identified four meaningful positions of a stroke (catch, immersion, extraction and release). The timing difference (termed "offset") between the front and back paddlers, within each K2, at each stroke position was calculated, with zero offset indicating perfect synchronisation. Results showed almost perfect intra-rater reliability of this method. The intra-class correlation (ICC) ranged from .87 to 1.00, and standard error of measurement ( SEM) from 0 to 5 milliseconds (ms). Inter-rater reliability was substantial to almost perfect (ICC .72 - .94, SEM 2 - 6 ms). On average, 35 strokes were analysed for each Crew and the mean offset was 17 ms, or 5.7% of water phase duration. Crews were more synchronised at the catch (11 ms, 3.8%) than the release (21 ms, 7.2%). However, the stroke synchronisation profiles of the six sub-elite Crews varied considerably from each other. For example, the best performing male and female Crews had directly contrasting profiles. This suggests that there is no universal stroke synchronisation profile for well-trained sprint kayakers. This video-based method may aid future investigations on improving performance.

  • consistency in stroke synchronisatiom patterns of Crew Boat k2 sprint kayaking over a four week period
    ISBS - Conference Proceedings Archive, 2016
    Co-Authors: Pui W Kong
    Abstract:

    The purpose of this study was to compare the stroke synchronisation patterns of a sprint kayak Crew (two-seater K2) over a four-week precompetition period. This case study centred on two female paddlers from a national sprint kayak team. High-speed (120 Hz) sagittal-view videos were recorded of a 200-m timetrial each week, for four weeks. Video analysis identified the extent of stroke synchronisation within the Crew at four key positions of the stroke cycle (catch, immersion, extraction and release). Results showed similar patterns of offset across the four sessions, whereby the back paddler was either in time or slower to reach the catch position (91% of all strokes analysed), but faster to reach the release position (81% of all strokes analysed). It is likely that an experienced sprint kayak Crew may be identified by their stroke synchronisation pattern.

Vasileios Georgiadis - One of the best experts on this subject based on the ideXlab platform.

Marshall Boazyunus - One of the best experts on this subject based on the ideXlab platform.

  • kajian eksperimental dan numeris gerakan seakeeping kapal Crew Boat orela dengan variasi posisi foil belakang di arah vertikal
    2017
    Co-Authors: Marshall Boazyunus
    Abstract:

    Kapal Crew Boat adalah kapal yang khusus untuk mengangkut pendukung – pendukung pengeboran lepas pantai seperti personil, bahan bakar, air minum dan instalasi lepas pantai seperti seperti oil platform, drilling rigs, dll. Kondisi lautan yang tidak menentu menuntut seorang ahli perkapalan untuk merancang kapal dengan gerakan (seakeeping) yang kecil.Penambahan foil belakang dapat mengurangi gerakan (seakeeping) kapal tersebut. Sehingga peneliti melakukan penelitian terhadap peletakan posisi foil belakang yang paling efisien untuk mengurangi gerakan (seakeeping) pada kapal Crew Boat Orela. Pengujian dilakukan pada peletakan posisi foil untuk kedalaman 0.75T, 1.0T dan 1.5T dari permukaan air, dimana T adalah sarat kapal tersebut. Peneliti menggunakan pemodelan numeris dan pengujian di towing tank. Pengujian di towing tank dilakukan pada periode 0.5 s sampai 1.7 s. Software yang digunakan untuk pemodelan numeris adalah Ansys Aqwa. Dari hasil penelitian tersebut, peletakan posisi foil belakang pada kedalaman 0.75T memberikan gerakan (seakeeping) paling baik dengan memberikan penurunan sebesar 14.99% untuk heaving dan 34.89% untuk pitching dan pada kecepatan 22 knot mengalami penurunan sebesar 3.374% untuk heaving dan 19.73% untuk pitching. ========================================================= A Crew Boat is a vessel specialized in the tranport of offshore support personnel, deck cargo such as fuel, water and from offshore installations such as oil platforms, drilling rigs etc. The ocean. The uncertain sea conditions require a shipdesigner to design a ship with good motion (seakeeping).The addition of foil can reduce the motion of the vessel. So, the researchers conducted research on the laying of the most efficient foil position to reduce the motion (seakeeping) on Orela Crew Boat. The research is performed on the laying of the foil position to a depth of 0.75T, 1.0T and 1.5T from the water surface, where T is draft of the ship. Researchers use numerical modeling and experiment test. The experiment tests are carried out in the period of 0.5 s to 1.7 s. The software used for numerical modeling is Ansys Aqwa. From the results of this research, foil at a depth of 0.75T provides the best motion by providing 14.99% decrease for heaving and 34.89% for pitching when the ship is motionless and decreasing by 3.374% for heaving and 19.73% for pitching when the ships move in 22 knots.

Sulowes Siregar - One of the best experts on this subject based on the ideXlab platform.

  • kajian eksperimental dan numeris hambatan kapal Crew Boat orela dengan variasi posisi foil belakang di arah vertikal
    2017
    Co-Authors: Sulowes Siregar
    Abstract:

    Kapal Crew Boat digunakan untuk keperluan logistik dan juga antar jemput pekerja lepas pantai (offshore). Penambahan foil belakang (hull vane) pada kapal Crew Boat “Orela” terbukti dapat mengurangi hambatan kapal yang berujung kepada peningkatan performa kapal atas pertimbangan kecepatan, waktu tempuh, dan konsumsi bahan bakar kapal. Untuk mendapatkan pengurangan hambatan kapal yang optimum maka dilakukan pengujian kapal dengan foil belakang dengan variasi posisi diarah vertikal, yaitu kedalaman 1,5 T, 1 T, dan 0,75 T dari permukaan air. Jenis foil belakang dan strut yang digunakan sama dengan seri airfoil yang sebelumnya yaitu foil belakang menggunakan NACA seri 6 yaitu NACA 641212 dan strutnya menggunakan NACA seri 4 yaitu NACA 0010. Hasil pengujian menunjukkan bahwa pada kecepatan relatif rendah, penggunaan foil belakang menambah hambatan kapal. Pada kedalaman foil 1,5 T, 1 T, 0,75 T, masing-masing terjadi peningkatan hambatan sebesar 56,81 %, 30,5 % dan 9,04 % pada kecepatan 14 knot (Fn = 0,364). Pada kecepatan relatif tinggi, penggunaan foil belakang mengurangi hambatan kapal. Pada kedalaman foil 1,5 T, 1 T, 0,75 T, masing-masing terjadi pengurangan hambatan sebesar 0,87 %, 2,37 %, dan 5,08 % pada kecepatan kapal 24 knot (Fn = 0,623). ============================================================================================= Crew Boat is used for logistic purpose and to deliver or pick up offshore workers. The application of hull vane in Crew Boat approved in reducing the total resistance of the ship which lead to the increasing in ship’s performance. To obtain the optimum reduction of resistance, then conducted experimen of ship’s with vertical position variations of hull vane, namely 1.5 T, 1 T, and 0.75 T measured from water surface. The foil series used in hull vane and it’s strut are NACA 641212 and NACA 0010 based on the previous research. The application of hull vane in relatively low speed increase the total resistance of the ship. Each positions 1.5 T, 1 T, 0.75 T, give the addition of resistances by 56.81 %, 30.5 % and 9.04 % in speed 14 knots (Fn = 0.364). In relatively high speed the application of hull vane decrease the total resistance of the ship. Each positions 1.5 T, 1 T, and 0.75 T, give the reduction of resistance by 0.87 %, 2.37 %, and 5.08 % in speed 24 knots (Fn = 0.623).

Ndaru Yandecantya - One of the best experts on this subject based on the ideXlab platform.

  • modifikasi sistem kelistrikan kapal offshore Crew Boat akibat perubahan penggerak bow thruster dari motor hidrolik pto engine menjadi penggerak motor elektrik
    2015
    Co-Authors: Ndaru Yandecantya
    Abstract:

    Kegiatan eksplorasi dan produksi minyak dan gas bumi di lepas pantai selalu membutuhkan suplai berkala. Crew Boat atau biasa disebut kapal kru adalah kapal yang digunakan untuk mengangkut kru dan supply ke offshore platform, antara lain makanan, air bersih, bahan bakar, peralatan, atau material yang dibutuhkan offshore platform. Kinerja Crew Boat sangatlah penting baik dalam kecepatan dan ketepatan manuver. Bow Thruster merupakan peralatan yang sangat penting untuk menunjang sistem kerja manuver kapal Crew Boat. Untuk itu perlu dicarikan solusi yang tepat, yaitu dengan merancang bow thruster bertenaga elektrik dengan sistem kontrol yang mudah. Dalam penelitian ini dilakukan modifikasi penggerak bow thruster bertenaga engine PTO menjadi tenaga listrik. Dalam penulisan skripsi ini saya memodifikasi sistem gerak bow thruster yang mana hasilnya sebesar 30 kW sebanyak dua buah yang harus terpasang di kapal. Dengan demikian maka dirubahlah sistem kerja generator yang awalnya single operation menjadi paralel operation dengan tanpa merubah kapasitas generator yang ada. MSB yang sudah ada juga dimodifikasi dengan penambahan sistem sinkronisasi dan MCB 160A untuk pengaman bow thruster setelah dilakukan modifikasi. ===================================================================================================== Exploration and production of oil and natural gas off the coast always require regular supply. Crew Boat or commonly called the Crew aboard the vessel that is used to transport Crew and supplies to offshore platforms, such as food, water, fuel, equipment, or materials needed offshore platforms. Performance Boat Crew is very important both in speed and precision maneuvers. Bow Thruster is an essential equipment to support the work system to maneuver the ship Crew Boat. For that we need to find the right solution, namely to design a bow thruster electric powered with a simple control system. In this research, bow thruster propulsion modification PTO-powered engine into electrical power. In writing this essay I modify the motion of bow thruster system which is the result of 30 kW as much as two to be installed in the ship. Thus dirubahlah generator working system that was originally a single operation into a parallel operation without changing the existing generator capacity. Existing MSB is also modified by the addition of the synchronization system and MCB 160A for the safety of bow thruster after the modification.