Seakeeping performance of semi-swath in following sea using controlled fins stabilizer

Semi-SWATH ship design is a result of combining the good features of SWATH and Catamaran designs. However, the disadvantage of semi-SWATH is that she has low restoring force at bow that causes a tendency to bow-dive when running in following seas. In some critical conditions, the foredeck was found...

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Main Author:	Rahimuddin, Rahimuddin
Format:	Thesis
Language:	English
Published:	2013
Subjects:	VM Naval architecture Shipbuilding Marine engineering
Online Access:	http://eprints.utm.my/id/eprint/37934/1/RahimuddinPFKM2013.pdf
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id	my-utm-ep.37934
record_format	uketd_dc
spelling	my-utm-ep.379342018-04-12T05:37:42Z Seakeeping performance of semi-swath in following sea using controlled fins stabilizer 2013-04 Rahimuddin, Rahimuddin VM Naval architecture. Shipbuilding. Marine engineering Semi-SWATH ship design is a result of combining the good features of SWATH and Catamaran designs. However, the disadvantage of semi-SWATH is that she has low restoring force at bow that causes a tendency to bow-dive when running in following seas. In some critical conditions, the foredeck was found to be immersed underwater. One of the efforts to improve the ship’s performance is to install fin stabilizers at bow and stern. The fin stabilizers are used to compensate for the low restoring force at the bow by increasing the lift force and damping force. A fuzzy logic controller developed for the system gives the ability to transform human knowledge and experience into the controller system and also to regulate the fin angle. A numerical simulation program developed in time domain for surge, heave, and pitch motions are then validated by seakeeping tests in towing tank of Marine Technology Centre, Universiti Teknologi Malaysia. Using the simulation program, parametric study was conducted to relate the ship and wave parameters with the ship’s performance characteristics. The ship with fixed fin stabilizers has the bowdive and immersed foredeck conditions at the following situations: for wave height to length ratio, Hw/Lw = 0.07, the wave to ship length ratio is 1.1 = Lw/Ls < 1.4, and for Hw/Lw = 0.08, the wave to ship length ratio is 1.0 = Lw/Ls < 1.7. For ship with active fin stabilizers, at Hw/Lw = 0.08 and Lw/Ls > 1.6, it was found that the foredeck was immersed with low surfing speed. Meanwhile, for the ship with fixed fin at bow and active fin at the stern, it was found that bow-diving and immersed foredeck did not occur. 2013-04 Thesis http://eprints.utm.my/id/eprint/37934/ http://eprints.utm.my/id/eprint/37934/1/RahimuddinPFKM2013.pdf application/pdf en public phd doctoral Universiti Teknologi Malaysia, Faculty of Mechanical Engineering Faculty of Mechanical Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	VM Naval architecture Shipbuilding Marine engineering
spellingShingle	VM Naval architecture Shipbuilding Marine engineering Rahimuddin, Rahimuddin Seakeeping performance of semi-swath in following sea using controlled fins stabilizer
description	Semi-SWATH ship design is a result of combining the good features of SWATH and Catamaran designs. However, the disadvantage of semi-SWATH is that she has low restoring force at bow that causes a tendency to bow-dive when running in following seas. In some critical conditions, the foredeck was found to be immersed underwater. One of the efforts to improve the ship’s performance is to install fin stabilizers at bow and stern. The fin stabilizers are used to compensate for the low restoring force at the bow by increasing the lift force and damping force. A fuzzy logic controller developed for the system gives the ability to transform human knowledge and experience into the controller system and also to regulate the fin angle. A numerical simulation program developed in time domain for surge, heave, and pitch motions are then validated by seakeeping tests in towing tank of Marine Technology Centre, Universiti Teknologi Malaysia. Using the simulation program, parametric study was conducted to relate the ship and wave parameters with the ship’s performance characteristics. The ship with fixed fin stabilizers has the bowdive and immersed foredeck conditions at the following situations: for wave height to length ratio, Hw/Lw = 0.07, the wave to ship length ratio is 1.1 = Lw/Ls < 1.4, and for Hw/Lw = 0.08, the wave to ship length ratio is 1.0 = Lw/Ls < 1.7. For ship with active fin stabilizers, at Hw/Lw = 0.08 and Lw/Ls > 1.6, it was found that the foredeck was immersed with low surfing speed. Meanwhile, for the ship with fixed fin at bow and active fin at the stern, it was found that bow-diving and immersed foredeck did not occur.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Rahimuddin, Rahimuddin
author_facet	Rahimuddin, Rahimuddin
author_sort	Rahimuddin, Rahimuddin
title	Seakeeping performance of semi-swath in following sea using controlled fins stabilizer
title_short	Seakeeping performance of semi-swath in following sea using controlled fins stabilizer
title_full	Seakeeping performance of semi-swath in following sea using controlled fins stabilizer
title_fullStr	Seakeeping performance of semi-swath in following sea using controlled fins stabilizer
title_full_unstemmed	Seakeeping performance of semi-swath in following sea using controlled fins stabilizer
title_sort	seakeeping performance of semi-swath in following sea using controlled fins stabilizer
granting_institution	Universiti Teknologi Malaysia, Faculty of Mechanical Engineering
granting_department	Faculty of Mechanical Engineering
publishDate	2013
url	http://eprints.utm.my/id/eprint/37934/1/RahimuddinPFKM2013.pdf
_version_	1747816512333283328

Seakeeping performance of semi-swath in following sea using controlled fins stabilizer

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