Planet Solar catamaran with sails

Discussion in 'Boat Design' started by Red Dwarf, Jul 7, 2012.

  1. Red Dwarf
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    Red Dwarf Senior Member

    In case you don't know this boat is the first to go around the world using solar power.

    http://flickrhivemind.net/Tags/planetsolar/Interesting

    It is very slow, 5 knots and seems to ride poorly. Regardless I like the idea and the layout. With better designed hulls I'm sure the ride could be fixed.

    It seems to me the solution is to dump the solar panels and put a sail on it. It would be much faster and still solar (wind) powered.

    So what does everyone think about a half scale version (50-60 ft) with a Dynarig sail?:cool:
     
  2. Luc Vernet
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    Luc Vernet Senior N.A.

    Although NZ designed (Naval Architecture by Craig Loomes), this boat has been built not only for Research and Development, which is interesting, but also for the promotion of Swiss solar technology, into which this country is investing heavily. It is, basically, a commercial venture, and wanting to benefit from the TVs and other medias "free" promotion. It also intends to carry up to 40 passengers, but the already very poor performance will then be drastically reduced.

    There is no discussion that solar powered boats have some future: water taxis in Venice and on the Leman lake are working well, but to forget that wind (= solar, yes!!!) is usable far more efficiently is saddening. However: nothing beats a good diesel, at the moment (and fuel comes, originally, from solar energy too....fossilized ;) ) when one considers the cost of the "wind engine", this at least for boats doing what most sailing yachts do: very little use of their sails!

    As far as your other question (Dynarig) is concerned: Mr. Brian Eiland will surely chime in, but there are many other sail arrangement at least as efficient as Dynarig, whose one of the major problems is the adjustment in sail curvature. Maltese Falcon pays that by poor windward performance, and extreme heeling, while very fast indeed on a reach.

    Would be effectively very funny to see a trimaran "looking like" Planet Solar and taking over this contraption with four or five times the speed! :D :D :D
     
  3. CDK
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    CDK retired engineer

    Are you sure about water taxis in Venice? Last time I was there they had Sofim (Fiat) diesels with Alpha-1 stern gear.
     
  4. Fanie
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    Fanie Fanie

    So it's going to be a sailboat again
     
  5. Luc Vernet
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    Luc Vernet Senior N.A.

    Not exactly "Water Taxis", and anyway not solar powered, but the "Vaporetto Electrico" has been in service 20 years ago (don't know if still in use?). Sorry for mixing electrically powered and solar battery charging: you are right if strictly speaking. However, the Swiss are (most probably - and maybe already!) going to close the deal in Venice for solar battery charging proper water taxis similar to those already operating commercially of Lausanne.

    Solar passenger boats designed by Incat Crowther operate from Sydney harbor, to cite another example.
     
  6. MechaNik
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    MechaNik Senior Member

    Asking a solar boat to perform continuously and through the night seemed like a big ask. Planet solar would be much more practical as a day boat or weekend tripper.
    With charged batteries and good sunlight I understood 15knots was the peak speed which is rather usable.
    Anyway, supplemented with even the simplest of sailing rigs this event would have been a breeze.
     
  7. Timothy
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    Timothy Senior Member

    Not a cat and not exactly a Dyna rig but Here is my kick at the can. No beauty but I need a platform to carry a 3000 plus watt solar array to power Torqueedo electric outboard and house systems ,that folds from 60' to less than 20'for container shipping and is still light enough to be pulled by an SUV. The rig has to carry almost 1000 sq' of sail but safely collapse to 18.' I think a sort of sliding lug rig could be made to work. A single symmetrical sail, attached by full length battens under tension to sliding yards in sleeves fitted with camber inducers at either end, and free to rotate around a tabernacle mounted telescoping mast, would be induced to form the desired shape as the yards are hauled fore and aft by opposing luff parrels that double as down hauls. and the camber inducers come into contact withe the battens at the new luff. Even on a rig inclined to windward the sail shape could be maintained. Unlike the Dyna rig the CE would be aft of the mast and twist would be in the right direction so the yards would not need to be fixed to a rotating mast. Attached is a short animation to illustrate the concept
     

    Attached Files:

  8. Red Dwarf
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    Red Dwarf Senior Member

    Wow that is very cool. If you can make all those joints handle the loads you have a winner.

    I too want to have the yards slide up and down a fixed mast. But I am a bit confused by your description.

    What makes it different than a Dynarig?

    Can you elaborate on the following statements?

    "would be induced to form the desired shape as the yards are hauled fore and aft by opposing luff parrels that double as down hauls. and the camber inducers come into contact withe the battens at the new luff."

    "Unlike the Dyna rig the CE would be aft of the mast and twist would be in the right direction so the yards would not need to be fixed to a rotating mast."


    Thanks and please keep us posted on your progress.
     
  9. Red Dwarf
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    Red Dwarf Senior Member

    Luc - Can you go into more details regarding this statement? "there are many other sail arrangement at least as efficient as Dynarig, whose one of the major problems is the adjustment in sail curvature"

    I would like to learn more about this and have sent you a PM.
     
  10. rwatson
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    rwatson Senior Member

    I can see lots of good ideas in this design.

    Just one more improvement to consider - make the windward side of the sails with a shiny silver surface to reflect more light onto the solar cells. :)
     
  11. masalai
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    masalai masalai

    Whilst some alternatives may look "cool" the ability to capture enough energy directly from the sun via PV panels, to enable continuous travel at "respectable speed", - will not be achieved in my lifetime... Remember, with sails up the sun is likely shading the PV (solar) panels - It is one or the other - PV panels occasionally, or, sails most of the time... and to carry that PV panel weight and expense for very occasional use, WTF for? Install a small diesel auxiliary and be sensible about it...

    'CNO' (my boat):
    My boat, 'CNO', is near fully renewable and it will do 10 knots on coconut oil using a pair of 20hp kubota / nanni sail-drive units - - warmer climates only, as CNO (CocoNutOil) solidifies around 25deg Celsius . . . and do that continuously for 166 hours from full fuel tanks... The PV panels are for ships services, house supplies and galley... My boat has 8 PV panels at present, but with 13 @ 195 W each the rated output is 2.5KW which, while the sun shines vertically above I may achieve 5knots but more likely a mere 2knots - Not worth considering as prime power and not enough to consider "hybrid electric power" on a cost basis...

    'Pelena Express'
    There is another boat "Pelena Express" operating in the Western Province of the Solomon Islands that also operates on coconut oil and is used as a fast (water-jet/Cummins) ferry service... Its service speed is around 20knots...

    'Planet Solar'
    I am sure the designer of "Planet Solar" achieved the absolute maximum efficiency given the constraints of carrying a maximum effective area of PV panels possible... No amount of pontification will improve on a significant landmark for PV panel derived solar-electric marine voyaging...

    Proven sail technology
    Sails cost to maintain but they have proven their ability to power boats around the world bloody fast and regularly race to prove such performance - As many others have said, THAT TOO is solar powered... and to date has the best long distance speed record for "renewable energy" and still offer a commercial return (not necessarily racing but at least retired to a life of recreational charter work...
     
  12. masalai
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    masalai masalai

    Better still paint photovoltaic capacity on both sides of the sail (the sun may be on the other side of the sail to the panels) :eek:
     
  13. masalai
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    masalai masalai

    May I suggest looking at the standard fore/aft set, as on most yachts? I would suggest that they are so popular in part because they are generally effective on most points and a sail to meet most conditions is already developed... and then consider the level of technology and material to lay - cut - & sew, as available in many different regions... The Arab-dow, Chinese-Lug, Crab-claw, square-rig, Hitch-hiker and the list goes on... All have merit and effectively meet a particular set of circumstances and needs... None, I would be so bold as to declare, will be deemed to be the best, or perfect for all occasions...
     
  14. Luc Vernet
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    Luc Vernet Senior N.A.

    I have read your PM.

    Concerning Dynarig, you will find references of Gerard Dijkstra publications on his website: http://www.gdnp.nl/ / Company profile. There is one specially interesting that he published at the HISWA symposium about Maltese Falcon construction/realisation. Please search as I do not have the reference on the web of this publication.
    During his researches, he envisioned many different rigs, including very large Aerorig, that, if I recall correctly, showed superior results than the Dynarig, but the latter was chosen essentially due to the ease of maneuvering. However, there has never been any possible comparison between the Aerorig and the Dynarig (in that size: maybe some smaller experiments???), but only against the sloop rigged Mirabella V.

    Joe Vittoria, first owner of "Mirabella V", was impressed by the ease of handling of this entirely "push-button" boat that is Maltes Falcon (a few hundred things able to fail, but so far so good!). During the one and only "regatta" opposing "Mirabella V" and "Maltese Falcon" (officially, Mirabella V is not allowed to race by it's insurance company), Maltese Falcon showed superior speed due to his longer waterline but also impressive VMG due to the remarkable power delivered by the Dynarig, although Maltese Falcon was unable to do better than 100deg. tack to tack while Mirabella V was doing 90. Mirabella V also proved faster in lighter winds.

    One thing to be said about the heeling I mention of Maltese Falcon is that this slender hull (this hull was build for another project) was designed for some 20deg. heeling, which is a lot for a boat that size (10 to 15 is more common), and that the curved sails (could more accurately say: curved yards, which impose their shape to the sails) of Maltese falcon were designed to match this heeling angle for maximum efficiency. This boat sails with the leeward side deck sometimes right underwater!

    The choice of very curved yard, then, is not an obligation on Dynarig, and flatter sails could be used. The thing is that, once this curve is decided, that is it. The Aerorig, instead, and which is basically a fore and aft rig (although it can be squared) can adjust it's sails much better, just by sheeting more or less, like a conventional sloop, or multimasted schooner as had been envisioned for the Maltese Falcon.

    Another problem with Dynarig concerns tacking. While gybing is the easiest thing, tacking almost stops the vessel. I remember a very good video on Youtube, though (please search), where Maltese Falcon is tacking in the middle of a crowded fleet: impressive!

    All this to say, just like Mr. Malasai just wrote, that there is no "best". Dynarig got it's great points and limitations, just like any other! In my post that you cite there, I would certainly consider another rig - or dynarig at least with flatter sails - on the very fast trimaran that Planet Solar would be if she had sails!!! Will add that a light multihull with Dynarig would be totally unable to tack...unless using it's engine... or accepting to go in astern for a while!
     

  15. Timothy
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    Timothy Senior Member

    " and to carry that PV panel weight and expense for very occasional use, WTF for? Install a small diesel auxiliary and be sensible about it..." I agree that diesel is still the most efficient and least expensive way to go. There are however perceived benefits that solar electric propulsion provides (clean ,quiet ,low maintenance?).I think given enough real estate the problem is weight and windage rather than power, and if the SOR as is the case with this concept requires that the boat is to be primarily sailed in daylight and motored only when there is no wind, or in and out of constricted areas, then with current lithium ion technology sufficient energy storage without a significant weight penalty is achievable using only the house bank . I tried wherever possible to use the solar panels in the overall panel design so that of a total panel area of 1600 sq ft only the difference in weight per sq ft of the solar panels compared to the equivalent foam sandwich panel is weight penalty. The sail itself would be Cuben fiber which is extremely light weight and highly reflective. Under sail even with all the windward solar panels shadowed by the sail, ambient and reflected light would still provide enough energy to keep up with house loads. At anchor or under motor the rig would be collapsed and the affects of the shadow cast by the 20' mast should be negligible. I might add that in this application a diesels primary function would not be for propulsion but for energy production and as it would be run for only about two hours a day, it and the fuel required would be unnecessary weight the rest of the time. There are indeed a lot of ifs buts and thens in this concept. I am having fun trying to resolve them and appreciate any relevant criticism or suggestions.
     
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