Stability/most-stable - catamaran, trimaran, pentamaran?

Discussion in 'Multihulls' started by big_dreamin, Jan 4, 2014.

  1. big_dreamin
    Joined: Jan 2014
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    Location: Minnesota

    big_dreamin Junior Member

    For a long time i'd been planning either a catamaran or an ILAN trimaran type design if I ever get to pursue a dream of building an oceangoing liveaboard. In one of my random searches the other day I came across this though:

    From this article http://www.scirp.org/journal/PaperDownload.aspx?DOI=10.4236/jtts.2012.22012

    "Bonafoux et al. [16] undertook a comparative study between three key hull forms, namely a monohull, a catamaran and a newly developed multihull version called a “pentamaran”. To make the different vessel de-signs comparable, it was assumed that all vessels had the same payload capacity as well as the same fuel load and engine. The catamaran was rated best in “motion sick-ness incidence” (MSI) in beam seas. In other measure-ments, such as wave wash, heave response, slamming and head seas performance, the catamaran performance was rated as the weakest, whereas the pentamaran hull form showed very strong results [see also 6]. A further disadvantage of the catamaran is related to the bridging structures between the hulls, which are often considered the most serious problem associated with the safety of multihull vessels [17]. Another study, conducted by Inoue and Kamruzzaman [18], reported that the size and fineness of the bulb are significant factors in reducing the motion response and the relative wave height under the deck structure of multihull vessels."

    references show:
    [6]
    G. A. Thomas, M. R. Davis, D. S. Holloway, N. L. Wat-son and T. J. Roberts, “Slamming Response of a Large High-Speed Wave-Piercer Catamaran,” Marine Technol-ogy and SNAME News, Vol. 40, No. 2, 2003, pp. 126-140.
    [16]
    J. Bonafoux, E. Dudson and D. Sherwood, “An Evalua-tion of the Effect of Hull Form Choice on the Operability of Fast Ferries,” Nigel Gee and Associates Ltd., South-ampton, 2001.
    [17]
    G. Bulian, A. Francescutto and I. Zotti, “Stability and Roll Motion of Fast Multihull Vessels in Beam Waves,” Ships and Offshore Structures, Vol. 3, No. 3, 2008, pp. 215-228. doi:10.1080/17445300801990913
    [18]
    Y. Inoue and M. Kamruzzaman, “Analysis of Hydrody-namic Characteristics for Arbitrary Multihull Ships Ad-vancing in Waves,” Journal of Marine Science and Tech-nology, Vol. 13, No. 3, 2008, pp. 231-243. doi:10.1007/s00773-008-0001-x

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    Since the specifics are a bit beyond me, could anyone either help parse or comment on the current state of the art on what will give the most comfortable ship at sea, for a given sea state, carry weight and so forth? Is it still the catamaran? A modified catamaran? What even is this pentamaran hull they talk of?
     
  2. rogerf
    Joined: Apr 2012
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    rogerf Junior Member

    The title of the study indicates the limits of the study ie high speed catamaran ferries in two specific locations. It does not include all catamaran ferries in the same locations or other forns of multihulls in any other place.

    John Shuttleworth has undertaken studies into stability of mono and multihull forms, you can view them here.

    http://www.john-shuttleworth.com/Articles/NESTalk.html
     
  3. redreuben
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    redreuben redreuben


  4. Ad Hoc
    Joined: Oct 2008
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    Location: Japan

    Ad Hoc Naval Architect

    How long is a piece of string...??

    There is no simple answer, since it is related to the SOR of the vessel and also the final price.

    All vessels, whether, mono, cat, tri, swath, penta, can be good. Are they good in all conditions, wave spectra and in all loadings etc etc...ahh..that's the million dollar question.

    You can separate out each individual aspect of what makes a boat great or good for seakeeping, but that misses the whole point. Since a successful design is greater than the sum of its individual parts.

    For example, best seakeeping, fro motions etc...a Swath, by far, no question. Draw backs...very draggy..i.e. more power required, thus big engines..more money more weight. Very weight sensitive etc etc.

    Thus there is no simple answer. The best, is whatever your budget allows for that is specified in the SOR.
     
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