tunnel influence on resistance in catamarans

Discussion in 'Multihulls' started by visnu, Dec 31, 2008.

  1. visnu
    Joined: Mar 2008
    Posts: 3
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: cochin,india

    visnu New Member

    First of all a very happy new year greetings to all. My current project as per our university syllabus includes the design of a high speed catamaran, pax 340 and speed 35 Kn, semi-displacement hull. I kindly request you to please help me with the following:

    a) what effect does the tunnel height of the catamaran have on the resistance
    my main particulars are : L =43.1 m, b = 3.9m, B = 12.6m.
    b) how to determine the wave height generated due to the vessel motions

    If there is a webpage link of reference to the above, can you please forward it as well???

    Thanx again....
  2. masalai
    Joined: Oct 2007
    Posts: 6,823
    Likes: 121, Points: 0, Legacy Rep: 1882
    Location: cruising, Australia

    masalai masalai

    Visnu, as a university student? you should be doing your own research not asking others to do it for you...

    If you own a computer and have access to reasonable broadband (via the internal services of your university) and you can download a variety of marine design software for free (professional stuff - not pirated - is very expensive when compared to your - Indian remuneration levels) so google "freeship" - it runs on windows 98 etc as does a free version of "delftship" and a Russian version called "Freeship!+" all based from the same origin...

    There is also a "free" version of Godzilla/Michilet look up Rick Willoughby a regular on this net for assistance here - it was written by Leo Lazerous (not sure of the spelling), based in South Australia....

    the search engine on this site is "google" so searches herein should be quite easy - just make sure it is only searching internally unless you wish to mount a global search but you may be overwhelmed by the volume you must sort through...

    35 knot cruise is bloody fast and would most likely not be viable in India due to the operating costs and maintenance levels necessary.... Have a look at the designs (you will only get to see simple marketing views) at "incatcrowther" - http://www.incatcrowther.com/

    A commercial ferry service (look around the website for fares and other costings etc http://www.sunferries.com.au/ Australian $1.00 - about 33 rupies Indian Wholesale exchange rate (interbank)....

    You are looking at a bloody big boat for 340pax and a fairly narrow beam overall - what sort of waters? sheltered or open? additional luggage considerations and the average weight of the passengers and their current fair structure viaq existing services - you need to do a SWAT and other marketing analysis, - or, - declare the "givens" as constraints imposed by the person/company that commissioned the design. In that case they would also stipulate the other figures - then you can say "your expectations for operating efficiency (running costs) are unlikely to be achievable and you need to consider your choices and options...."

    http://apyachts.com.au/boat.php?de=41579 this one I know and it used to work the Townsville and nearby islands carrying around 130pax (semi sheltered waters) and would only handle seas to about 1.5m at slower speeds otherwise cruise at 20knots on 20 minute to 1 hour runs....
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