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Seakeeping evaluation of semi-swath vessel in head-seas using time domain simulation

Ahmad Fitriadhy, Ahmad Fitriadhy (2007) Seakeeping evaluation of semi-swath vessel in head-seas using time domain simulation. Masters thesis, Universiti Teknologi Malaysia, Faculty of Mechanical Engineering.

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Small Waterplane Area Twin Hull (SWATH) and Catamaran vessels are known to have more stable platform as compared to mono-hulls. A further advantage of SWATH as compared to Catamaran is its smaller waterplane area that provides better seakeeping qualities. However, the significant drawback of the SWATH vessel is when encountering head-sea at high forward speed. Due to its low stiffness, it has a tendency for large pitch motions. Consequently, this may lead to excessive trim or even deck wetness. This phenomenon will not only degrade the comfortability but also results in structural damage with greater safety risks. In this research a modified SWATH design is proposed. The proposed design concept represents a combination of Catamaran and SWATH hull features that will lead to reduce in bow diving but still maintains good seakeeping capabilities. This is then called the Semi-SWATH vessel. In addition, the full-design of this vessel has been equipped by fixed fore fins and controllable aft fins attached on each lower hull. In the development of controllable aft fins, the PID controller system was applied to obtain an optimal vessel’s ride performance at speeds of 15 (medium) and 20 (high) knots. In this research work, the seakeeping performance of Semi-SWATH vessel was evaluated using time-domain simulation approach. The effect of fin stabilizer on the bare hull performance is considered. The validity of numerical evaluation was then compared with model experiments carried out in the Towing Tank at Marine Technology Laboratory, UTM. It was shown that the Semi-SWATH vessel with controllable fin stabilizer can have significantly reduction by about 42.57% of heave motion and 48.80% of pitch motion.

Item Type:Thesis (Masters)
Additional Information:Thesis (Sarjana Kejuruteraan Mekanikal)) - Universiti Teknologi Malaysia, 2007; Supervisor : Assoc. Prof. Dr. Adi Maimun
Uncontrolled Keywords:small waterplane area twin hull (SWATH), Catamaran vessels, pitch motion stabilizations, ride-control system
Subjects:T Technology > TJ Mechanical engineering and machinery
Divisions:Mechanical Engineering
ID Code:9682
Deposited By: Ms Zalinda Shuratman
Deposited On:20 Jan 2010 02:55
Last Modified:31 Oct 2012 01:30

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