Kite power for boats - boats powerd by kites

Discussion in 'Boat Design' started by 4wings, Jun 18, 2012.

  1. 4wings
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    4wings Junior Member

    I want to start this new thread for everybody interested in the possibilities to power his boat ( sail or power or kayak ) temporary by a traction kite as they are used by kite surfer.
    Main reason is that there are a lot of mysteries in this field where two sports are so in line and still so far apart ... I hope as many people are willing to chip in, ask questions , leave ideas for others to chew in as possible ...
    So far this topic is buried in other threads and often hard to find.
    For the last 7 years we follow the development of traction kites and played with the thought of a kite sailer - which we started last year in winter feel free to take a look at http://www.kite-sailer.com.
    This initial post is a combined mix of answer we gathered in this field and links to help you understand some aspects - but I assume it is far from perfect ....
    The kite - are sold by square meter area - in high aspect and low aspect ratio ...and you can compare them to your sail area or HP -
    In one of the threads here you find the formula of 1 sqmeter kite = to 2 HP on engine in best case scenario or 1.5 hp in normal conditions ...which is quite accurate to estimate the size of kite you need to power your boat - as you know your HP
    Kite lines - please see : http://http://www.kite-sailer.com/cb.html where we combined the core of a long discussion in a kite surfing forum - you can apply this knowledge to your boating application as well as there is no change in the physics ...
    The control bar - which would allow you to steer the kite is the link between the end of your kite lines and your boat deck - the guys at http://www.kite-boat-systems.com/ have a ready made solution for you but feel free to copy our design if you desire so ... since it is a more or less straight forward approach
    Most current kites are 4 line kites -
    2 Power lines ( which actually come into one line at the end and are attached via chicken loop to the kite surfer in the surfing application ) which carry the main load and 2 steering lines on a bar - which carry lower load but still can do harm.
    I believe most common misconception is that you buy a kite and get going - as such please get a trainer kite first and play on the beach to get a idea about handling , power window and forces ...
    We used a Airush Supra TI Inflatable Trainer Kite which is a 4 line kite and gives you a good feeling ( just throw the bar away and use any other bar even a broomstick with holes and lines in it would work better)
    Once you got a grip determine the size of the kite you need - for a touring kayak the trainer kite will work great - hold in mind if you overpower the boat with the kite - you reduce your downwind possibilities as in the moment your vessel will reach wind speed - the kite will fall from the sky.
    Learn how to water start your kite which is relatively easy and the often seen obstacle of getting the kite in the air is less of a problem for recreational boating than it is for the commercial guy's which want to launch while under way.
    I hope I could get this ball into rolling and remember don't be ashamed of not knowing only of not desiring to know ..please ask questions
    Safe sailing
    Michael
    http://www.kite-sailer.com
     
  2. sabahcat
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    sabahcat Senior Member

  3. 4wings
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    4wings Junior Member

    Can you actively fly the kite / steer it or is it a straight downwind approach fixed ...?
    Michael
     
  4. Village_Idiot
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    Village_Idiot Senior Member

    So.... to get some of us started and build interest...

    Where do you find/purchase training kites, and how much are they?

    I remember seeing these in Tahiti a few years back, long before it was popular in the U.S. Lotsa kids on the shoreline practicing with kites, and the older kids (teens/twenties) out kitesurfing, doing flips, etc.
     
  5. 4wings
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    4wings Junior Member

    Well good question ...
    We got ours from : http://www.air-pirate.com/product/airush-3m-inflatable-trainer-kite-complete-- Nate was friendly and was able to answer a few related questions which were not kite surfing but kite boating related ...but please feel free to shop around if you are not in the US.
    Try to compare apples to apples as the airush is also available in a smaller version for a lower price - we paid 350,- including S/H and trainer kites ( if you do not tear them up ) hold their value quite well as the demand is higher than the supply - just search on e-bay for 3.5M trainer kite and you get a idea ...
    If you are member of a yacht club - you might share with others as you will get a grip on the kite within the first 10 - 15 hours of fun ...and thereafter will try to step up a notch ....let others experience and help them at the start up .....
    Manual off the airush website - http://gallery2.airush.com/share_gallery/2011ar/tech_support/2011%20SUPRA%20LINE%20MANUAL_ENGLISH.pdf
    Please hold in mind I was referring to the 4 line kite which is covered in the second section - as well as the powerlines we had attached to a belt belt via snap shackle ... that gives you the same setup as on a big kite.
    For the start ( first 4 hours ) it helps to have a second person help you till you get a grip on the water start and relaunch the kite by yourself without any help.

    Hope this will help you
    Michael
    http://www.kite-sailer.com


     
  6. 4wings
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    4wings Junior Member

    Collection of kite powered boats -

    To make it easier for most who follow this thread - I started to collect the links of kite powered boats at :

    http://pinterest.com/kitesailer/kite-powered-boats/

    Most recent actual craft was :

    http://www.powerkiteboat.com/en/index.html

    Most recent design study:

    http://www.yankodesign.com/2008/06/04/water-wind-fun/
    It looks cool - actual performance is something where I would love to see it beyond drawing board

    Hope you enjoy and it keeps your open mind fed
    Michael
    http://www.kite-sailer.com
     
  7. groper
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    groper Senior Member

    The real developments need to be made in kite control automation systems, and safe reliable launch and retrieval systems for kites to be useable in any other vessel besides small recreational type stuff.

    Do you know of any developments in the above areas?
     
  8. whitepointer23

    whitepointer23 Previous Member

    look up skysails
     
  9. Red Dwarf
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    Red Dwarf Senior Member

    If the price is low and the rig is simple a kitesail could be an emergency backup propulsion system.

    I don't see any for sale that are not custom made.
     
  10. 4wings
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    4wings Junior Member

    Thanks for your participation and input to this thread - allow me to answer some aspects - which is only my personal opinion - we all may differ on it.

    "The real developments need to be made in kite control automation systems"

    At this point we still have a very swift development on kites which increase their safety rapidly as well as their ability to make more use of the power window than 10 years ago - any development in automation would need to be flexible enough to adjust to different kite style and flying abilities.
    On the other hand - how many race cars have an automatic transmission ...?

    "safe reliable launch and retrieval systems for kites to be useable in any other vessel besides small recreational type stuff"

    I think for your intended size of boat the skysail system should work as you have sufficient space and funds. From a development aspect I assume we get further with 100 "small recreational type stuff" than 100 commercial type vessel which are at a workplace.
    I believe a 100 active minds have the ability to solve the main issues quicker as more people's minds get actively involved in solving different issues.

    Skysail did great work for commercial applications - just has a very conservative fly pattern for something which can create such a high amount of pumping power if in an active flight pattern - a bigger use of the wind-window would increase power output - but increase risk and reliability on an automated system - attached the wind-window graphic so all have an idea about the power zone / force direction of a kite.
    [​IMG]
    [​IMG]
    Please hold in mind the wind-window is seen in a 3D aspect

    "Price and simplicity"
    I guess we all want that ...as such here something to think about :

    Why do we see it always as one big kite - a tandem setup would change the pumping power into a more flat power curve , we would be able to change kites according to wind force while under way - kind of equal to reefing a sail - and reduce the so far massive kite size to smaller more manageable sizes which are not anymore custom made but kind of factory made which would reduce their cost.
    Sail boats have several sails to adjust to different conditions.
     
  11. brian eiland
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    brian eiland Senior Member

  12. groper
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    groper Senior Member

    4 wings,

    Ive been kiteboarding for over 12 years now and fully appreciate the power and efficiency a power kite provides. Mucking around with little stuff on recreational beach craft is fine, but nothing in this scene addresses the flight automation and launch / retrieve issues that prohibit safe use of these kites on larger but still private yachts. Im talking about your standard sailing yacht or sailing catamaran of around 40ft length for long distance cruising. Theres a tremendous market there, but the kites need to have an autopilot system and a means of launch / retreive without everything going FUBAR... whomever develops a working system for this, is going to make a mint...
     
  13. 4wings
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    4wings Junior Member

    Brian thank you for connecting these two threads ...there is a lot of info in the previous thread and I created this one only to share with a wider interest group -
    I want to point out that the numeric conversion ( 1 kite square meter = 2 hp under optimum conditions and 1.5 under normal conditions ) is highly appreciated not to overpower a kiteboat.
     
  14. 4wings
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    4wings Junior Member

    @Groper
    I would suggest the best lead in this direction is Don Montague @ http://www.project.kiteboat.com/and his team.
    Our direction is to build a kite efficient hull which accommodates lesser square meter kite and increases the safety of the boater as well as tandem setup as I mentioned before.
    This field is very new with still too many variables to be addressed.
    All the best
    Michael
    http://www.kite-sailer.com/
     

  15. 4wings
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    4wings Junior Member

    I tripped over this posting and assume for all which are interested in automation and launch and retrieval systems for bigger kites - we could lean on their research :
    http://www.lr.tudelft.nl/en/current/agenda/event/detail/stw-perspectief-2011-program-initiative-airborne-wind-energy-awe/
    As well as :
    http://www.kitepower.eu
    As the posting is a year old - some advance should be made till today
    all the best Michael
    http://www.kite-sailer.com
     
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