Low resistance powercat boat plan

Discussion in 'Boat Design' started by arthurcsb, Oct 30, 2012.

  1. arthurcsb
    Joined: Oct 2012
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    arthurcsb New Member

    I am currently doing R&D project on wing in ground craft. According to my research, a low resistance planing/semi-planing catamaran hull design would be most suitable for the craft design. However, I have no experience in designing a catamaran boat hull. Anyone can provide me a basic powered catamaran hull boat plan please? Thank you!
  2. sottorf
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    sottorf member

    I assume you are thinking of using a catamaran hull to overcome the resistance hump caused by hydrodynamic drag on the hull just before take off. I dont think a catamaran is the right choice for that. The designs I have seen make use of stepped monohulls or SES hulls. My knowledge is hower limited. I propose you post you question on the WIG page http://www.se-technology.com/wig/index.php
  3. masalai
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    masalai masalai

    Hi arthurcsb,
    Welcome to the forum, have a look at what "groper" is doing, and I recently drove mine some 900 N Miles from Brisbane to Cairns - build is partially outlined on the thread - "my little piece of peace"... I have a range of about 2000 N Miles on a tonne of fuel averaging 7.5 knots using a pair of nanni-sail-drives utilising a pair of 20hp kubota engines... My boat can fit sails but was prepared for extensive cruising in the tropics during the 'doldrum' season...
  4. groper
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    groper Senior Member

    arthur, i wish you good luck with your WIG project, there is much untapped market here for a successful machine in many markets. I have had significant exposure to such designs through my fathers work and extensive studies of the russian craft built to date - more work has been done by the russians than anyone else in this field which im sure your already aware of.

    Most of these craft to date, use a typical seaplane type catamaran form with a stepped planning hull. Planning hull theory is well covered on this forum and the internet in general, im sure you can find what your looking for on that score. The stepped hull is also well covered, you just need to be careful where you place the first main step with regard to the CoG of the machine, CoL of the main lifting surface and such so that you have a good balance and minimum drag in order to minimize the power required to break away from the water - as you already know the horsepower required then drops dramatically once airborne and flying in ground effect. The russians solution to this problem is often solved by the air cusion effect and blasting air from the props under the wing(s). This reduces the overall required engine size (and weight) to get the aircraft off the water.
  5. Leo Lazauskas
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    Leo Lazauskas Senior Member

  6. arthurcsb
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    arthurcsb New Member

    The most common hull design for WIG at the moment I found was monohull with outriggers on the wing tips which actually you may say is a trimaran configuration. Thus, I thought cat would be a better choice from resistance and stability perspective (I may be wrong). To be fair, this project is to look into experimental passenger craft. Thanks Sottorf!:)
  7. arthurcsb
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    arthurcsb New Member

    Thanks masalai and groper for your reply. I have had a look at the thread. unfortunately the link http://www.boboramdesign.com.au/39-c/ is not working anymore. do you have an updated link?
  8. Ad Hoc
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    Ad Hoc Naval Architect

    You need to separate the "hull" from the purpose and benefits of a WIG.

    Such as the ride height of WIG, the principal of controlled and level attitude to counter the pitching, the low aspect ratios plan forms and several other factors. In other words, doing more background into the factors that influence the efficiency and effects of WIGs. Once you have done that, then you can investigate which hull form is most suitable for your application with a degree of knowledge, rather than assuming a hull form from the outset.
  9. DCockey
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    DCockey Senior Member

  10. lucdekeyser
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    lucdekeyser Senior Member


    Ad Hoc is right about separating the concerns and then best amalgamating the design compromises. The popularity of the trimaran planforms is no coincidence: Going at speed the amas should be essentially out of the water. The stability of the remaining monohull is ensured by the speed in the water.

    WIG's are essentially about efficiency of flight. Do not get fooled by recreational craft using GE - a brick with enough power can also fly in GE. This efficiency is determined by the trick you design to get out of the water with power requirements that come as close as possible to the power you need to cruise in GE. It is that simple ;-)
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