New Age Trawler/Motorsailer; Kite assisted PowerYacht

Discussion in 'Boat Design' started by brian eiland, Nov 20, 2007.

  1. brian eiland
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    brian eiland Senior Member

    New Age Trawler/Motorsailer....Kite assisted PowerYacht

    New Age Trawler/Motorsailer; Kite-assisted PowerYacht

    I’ve come to a realization in this current age of escalating fuel prices, that there are two forms of pleasure yachts that are likely to survive the energy crunch, and even possibly flourish…the motorsailer and the kite-assisted power vessel.*

    There’s been much written about motorsailers, including my preference for the multihull form of that gender…basically a more easily driven hull for both the motor and sail power to act upon…greater range, more economy, better performance.

    Now we come to a new era, and again it’s the ‘fringe’ sailing youngsters that show us another way…kite sailing. You may have witnessed some of this activity out on the bays and the lakes where the windsurfers use to play. Check out this ‘YouTube’ clip,
    “I Can Fly”,http://www.youtube.com/watch?v=lkyOhyocw2E
    There is power in that wind to drive our vessels, and methods to extract it other than conventional vertical mast sailing rigs. Para-foil kites can produce very considerable power, and can be controlled in flight as the military discovered long ago. Now if we get those kites up into the better winds aloft, we can tap into that more consistent energy than exist at the sea level.

    Two companies that have been quite active in the promotion of driving ships with kite power are:
    1) KiteShip: http://www.kiteship.com/
    2) SkySails: http://www.skysails.info/index.php?L=1

    At present the Skysails group appears the more advanced of the two, particularly when you consider their single-line tethering, and computer flying of the kite. They have an automated stowage and deployment scheme as well. These parafoil kites can even fly upwind to certain degrees. A review of the websites is quite interesting. But they are not the only game in town, there is a lot of military interest in precision flying kites as well; ie, Atair Aerospace, http://www.atairaerospace.com/

    How might this kite business affect the yachting business? It goes back to idea of a motorsailer, or phrased differently, a ‘wind-assisted power vessel’. If we can optimize the economy of the power vessel, as the trawler concept seeks to accomplish, and then add ‘sail’ assistance, we have a recipe for a ‘future class of new-age trawlers’ that can be quite economical to operate, and have a great range. I believe this could be a very viable alternative yachtform for our new fuel future.

    Humphrey’s yacht design is very big on this idea as well. Attached is their tentative proposal for a 40M SkySail MotorYacht. They’ve termed it a SkySail-supplimented MotorYacht, "The use of the word ‘supplemental’ is chosen carefully. While we expect this family of boats to be able to ‘sail’ efficiently under SkySail, we foresee that fundamentally the boats have to be very efficient and seakindly motoryachts, and in this respect the common denominator for efficiently under both forms of motive power is low hull resistance. Thus our work on this generic set has evolved towards slender body hulls that derive stability from wavepiercing outriggers….they are in effect trimaran derivatives, which will have long rang capability under engine, not to mention the ‘free’ miles under SkySail."

    I have been following some of the ‘slender ship’ technology as it has cross-over potential with multihull technologies. For a few references, visit these websites, and see a few of the attachments I’ve provided:
    1) Worlds Largest Powered Trimaran : http://www.trimaran.dera.gov.uk/
    2) White Rabbit tri : http://www.yachtforums.com/forums/13292-post2.html
    http://yachts.monacoeye.com/yachtsbysize/pages/whiterabbit01.html
    3) Very Slender Vessel, VSV : http://www.specialboatservice.co.uk/vsv.htm
    http://www.globalsecurity.org/military/systems/ship/vsv.htm
    4) Cable & Wireless Trimaran :
    http://www.solarnavigator.net/history/cable_and_wireless.htm
    5) Catamaran Vessels : Lets not forget the catamaran hullform, they are in fact slender ships as well. As I wrote in a recent press release, “Our next design (coming soon) will be an adaptation of this new motorsailing catamaran design into a kite-assisted power cat. We will exclude the Dynarig sailing rig and substitute a SkySail kite rig. Next will be an entirely new hull design making use of the kite-sail concept


    Back to those design concept drawings by Humphrey’s (attached PDF). I can fully imagine a scaled-down version of this tri-hull design, in the 65-70 foot range, with a wonderful rear ‘swim’ platform deck incorporating a sportfishing arrangement and/or a Scuba diving platform. Just inside could be a tender stowage as shown; or rather a complete diving & fish tackle facility. The tenders could then stow up on rear deck, or one forward, one aft.

    The power would be a single main engine sized to develop the vessel’s desired top speed, and it could transmit this power by conventional shaft/prop arrangement, or with a azimuthing Volvo IPS dual prop unit, or via a retractable azimuthing Rim-Drive prop unit as I included on my latest dynarig motorsailer design.
    1) Volvo IPS : http://www.yachtforums.com/forums/yacht-reviews-feature-stories/7467-world-debut-volvo-pentas-new-ips-750-850-a.html
    2) Rim Drive : http://www.yachtforums.com/forums/technical-discussion/3961-rim-driven-propellers.html

    Supplementing this single main engine would be a single DC diesel/electric power unit to provide for:
    1) Ships electrical requirements
    2) Slow speed operation by electric (wing) motor belted to main prop shaft
    3) Maneuvering thrusters as required depending upon azimuth capabilities of main prop.

    The entire ship would be powered by only two engines, basically sized to provide:
    1) Full main diesel power, unimpeded by interceding diesel/electric conversion
    2) Slow speed operation and ship’s systems via the smaller diesel/electric unit
    3) ‘Twin power’ emergency backup as either engine can run all gear
    This configuration more ideally meets the latest thinking for the new diesel/electric DC technologies onboard smaller vessels. Alternatively, two identical diesel/electric plants might be sized such that in combination they would supply the max power required of the vessel, and half power for lesser times.

    Only two engines and no conventional sailing rig should make this a more affordable vessel, both in construction, in maintenance, and in operation. However the SkySail kite arrangement will probably more than offset the conventional sailing rig in cost. Possibly a less expensive alternative to this ‘brand name’, with less computerization could be found (no integrated weather/navigation features, etc). Light-weight construction would be desirable but not necessary. Third world hull construction materials are a possibility.

    I’ll call it a KiteSail Motorsailer for now.
    ....comments, suggestions


    * I must include a disclaimer that many ‘superyachts’ will also survive, as there will always be some people with unlimited funds to do whatever strikes their fancy regardless of price of construction and operating expenses.

    PS: I must give credit to Guillermo who brought this to my attention, "Brian: You should try this also for your big game fishing catamaran" at posting #285
     

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  2. Munter
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    Munter Amateur

    I think one of the stumbling blocks that may impact on the usefulness of the kite technology (which as a kite surfer I'm a big fan of), is the utilization factor that will be achieved in practice. How many superyacht owners are going to be happy to schedule their journeys in to match the conditions in which the kite will effectively assist? I fear that when scheduling constraints are applied to the movements of the ship the kite will only see limited use.
     
  3. brian eiland
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    brian eiland Senior Member

    Utilization Factor

    As a kite surfer I imagine you seek out the maximum fun (speed), and rarely
    experiment with how close you might be able to go to windward, or other sailing angles?? Correct me if I'm wrong.

    At this time there is virtually no organized racing in these kite (vessels), so very little experimentation in all of possibilities that might exist with these 'sailing' vessels? Beach type catamarans and windsurfers eventually developed a lot of head-to-head racing venues that further developed the capabilities of their sailing potential. I believe there is yet a lot to discover here in the 'sailing potential' of these kites.



    Granted the 'superyacht' owner will be less concerned with fuel bills and more with speed, so his use of kite-assist will likely be small, if at all. It's the gentlemen who sought out the trawler yacht rather than the fast power yacht that will be attracted to this alternative. And it could well be the sailor who grew a little old for the rigors of sail handling, and thus began looking at the trawler for its cruising attributes, that could be attracted to this 'new age' trawler/kitesail motoryacht.

    SkySails is fervently seeking to maximize the usable conditions that the kite can assist in propulsion, in order to sell the concept to the shipping industry. So advancements should come more quickly. Their website is pretty interesting.
     
  4. Munter
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    Munter Amateur

    Getting upwind is an important part of kiting. Its how you buy the room to make big jumps which inevitably cost you 10's of meters downwind loss.
    The upwind angles aren't as high as a racing yacht but they are still respectable.

    One thing that would make that upwind performance difficult to repeat with a motor yacht is the loss of the reflex like control that the rider has when the bar is directly in his hands and the board directly on his feet. A kiter is constantly playing a dynamic balancing game controling kite line pressure, kite line angle and the angle of the board in the water (sideslip resistance). If this balance isn't maintained you can end up getting dragged downwind or falling back into the water. Replicating the instantaneous control of all those variables on a larger structure would be a complex task! As I understand it the kites were predonminantly intended to help with downwind sailing which I think would be an easier control task.

    I'd love to see kite-ships going upwind but I think they have a fair bit of development to go before it can be done.
     
  5. brian eiland
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    brian eiland Senior Member

    Good points Munter
     
  6. Fanie
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    Fanie Fanie

    If you have two pipes some distance from one another and some distance upwards (the outlet ends) these kites may well be easy enough to bring in, let out and may even prevent ropes from twqisting up.

    If you have the kite in, the whole kite is dragged into one pipe, so between the two pipes is only a rope. To let the kite sail out, pull so the kite is about midway between the two pipes, allowing the wind to catch and take it out. The pipes a distace from one another would prevent the ropes from twisting but will depend how far the kite is let out. To bring in is simply a matter of winching it in, then winch one side only so it is out of the wind in the one pipe. Just an idea.
     
  7. Guillermo
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    Guillermo Ingeniero Naval

    The SkySails system is based on the kite constantly flying in dynamic mode (figure of 8), this to generate dynamic stability and increased power.

    The kites are able to develope up to 2HP per sqm under the adequate conditions and, as they fly around 110º off the wind, you can even beat to winward with them (although less efficiently, of course). A 55º wind angle off the bow is possible.

    For the time being the system is relatively expensive, but probably price will come down with increasing production. I've been investigating applicability to fishing vessels (30 to 70 m trawlers) and the system pays back itself in around 3 years (We did detailed studies of real life conditions for three of such vessels, with the collaboration of their owners and captains). It can be mounted without much fuss in around a week at an existing fishing vessel's forward deck, after the proper detailed engineering study of feasibility, of course. We are trying to mount the system aboard one of such units and test it, not only for free running, but also for when under trawling operations, which is the most important aspect. The bad news is fishing-vessels owners are not easy to convince....;)

    Cheers.
     
  8. brian eiland
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    brian eiland Senior Member

  9. Guillermo
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    Guillermo Ingeniero Naval

  10. Pericles
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    Pericles Senior Member

  11. brian eiland
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    brian eiland Senior Member

    Good find Guillermo...that video.
    I haven't had time to look thru those references of Pericles yet. I'm sure somethings interesting

    Brian
     
  12. Guillermo
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    Guillermo Ingeniero Naval

  13. brian eiland
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    brian eiland Senior Member

    Attached Files:

    Last edited: Dec 23, 2007
  14. brian eiland
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    brian eiland Senior Member

    Kite Sail Cat

    Sorry for the rather rough sketch at the moment, but here is the kite-assisted power cat at the moment of launch.
     

    Attached Files:


  15. Pericles
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    Pericles Senior Member

    Brian,

    I truly hope this concept is taken up, because you have pioneered many really good ideas.

    Best regards,

    Pericles
     
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