Powered water seat

Discussion in 'Projects & Proposals' started by Luis Cunha, Oct 13, 2007.

  1. Luis Cunha
    Joined: Sep 2007
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    Luis Cunha Junior Member

    Dear Sirs,

    My name is Luis Sarmento Cunha, I live in Francelos, V.N.Gaia, PORTUGAL close to Atlantic Sea.
    I have just created an innovative water vehicle, the Powered Water Seat (PWS), but I have some questions regarding whether it is a feasible concept.
    The PWS is mainly composed of strong tubing, a power assembly mounted on one side of the tube, the seat system mounted on the other side and a hull (like a floater). The power assembly is mainly made up by an electric motor, electronics, batteries and a rudder. The seat system is the seat, controls and cardan.
    The hull is mounted on the tube and can move up and down, controlled by a driver.
    In my opinion the motor which powers the PWS should be electric but there are probably other better options.
    When the PWS is stopped, it stays balanced by the vertical tube and the seat positioned above the water surface. In this position the driver can look around or fish in a very comfortable position.
    To take a swim, the hull can move up and the person can then jump into the water.
    To start driving, the hull moves down, the person inclines forward and it start moving. The movement should feel like one is surfing.
    I'm not quite sure if I have explained my idea sufficiently well. I'm attaching some CAD photos that may elaborate further.
    I would very much appreciate your comments regarding this new concept and whether, in your opinion, it is feasible to build the PWS.
    If it is feasible, I will appreciate to have the cooperation of a fantastic designer in order to create a completely new concept of power boat.
    Thanks in advance for your co-operation.

    PWS - Driving front view.jpg

    PWS - Driving side view.jpg

    PWS - Stop front view.jpg

    PWS - Stop side view.jpg

    PWS - Taking a swim front view.jpg

    PWS - Taking a swim side view.jpg

    Luis Cunha
    Francelos, V.N.Gaia, Portugal
    Tel: 351 93 7894106
    luisscunha@clix.pt
     
  2. alan white
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    alan white Senior Member

    This seems to be very similar to a Starling Burgess design proposed maybe 75 years ago. I am trying to remember where I read about it.

    Alan
     
  3. Luis Cunha
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    Luis Cunha Junior Member

    Dear Alan White,

    It is an honour thinking that some of my ideas are close to the great and well known Starling Burgess.
    Thank you.
    Waiting your comments
     
  4. alan white
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    alan white Senior Member

    Somehow, I can't mentally place a person on it.
    Can you sketch a person where they belong on this thing?
     
  5. korvello
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    korvello Senior Member

    LUIS still waiting on a little better drawings :it looks like riding a unicycle ; propeller needs to be enclosed or is it a jet of some kind and may need a foil ,can't see why the seat has to move it will make it too complicated and harder to ride,may also need some kind of handle bars for atitude control......... oh well just my 2 cents and one will need good balance and luck probably.
     
  6. Luis Cunha
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    Luis Cunha Junior Member

    Korvello,


    Concerning propeller versus jet, I think both solutions are possible. It is necessary to check prices, power, weight and volume.

    In my opinion the seat has to move in order to give more comfort to the driver. You can get it using a special cardan.

    My idea is that the driver can control the position of the hull (red buoy), speed and direction of the movement.

    New drawings comming soon

    Regards
     
  7. korvello
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    korvello Senior Member

    I can see the seat being up or down affecting balance ,i just don't get is moving foward with buoy in the water how does pilot control toy;.... with leaning back or foward? ....it needs bars for atitude control, the motor will go foward and drag the pilot behind ,now there is an idea a one man ski machine........motor needs to be mounted on a tube or longer shaft with foils or something for some way or stabilizing it ......fascinating how fast are we talking about 2mph ,why not pedals and a human powered propeler there you will have a unicycle and maybe some balast will help too .......LUIS i hope you massage your drawings so far you have a sit -on buoy as i see it!............ but hey i have even crazier ideas so i'm sure we'd get along just fine .
     
  8. Vega
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    Vega Senior Member

    :D :D :D

    Stability and balance seems very problematic...I would say acrobatic. If you join the imponderables of sea motion I suspect only an acrobat or a computer controlled gyroscopic system will be able to control the craft.
    But I can be wrong and certainly it is an unusual approach.
     
  9. korvello
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    korvello Senior Member

    VEGA now that the big guns are getting involved maybe LUIS has a chance ,it also could be called the portuguese tread [nao sei se sera uma coisa boa]..........a lot is at stake here if the all thing fails .........still waiting on LUIS's new drawings ,what about a prototype?
     
  10. Luis Cunha
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    Luis Cunha Junior Member

    Hello Vega and Korvello,

    Thank you very much for your comments.
    My “defence” is as follows:

    1. Stability
    The natural position of the Powered Water Seat (PWS) is vertical with the seat up and motor down because the power assembly is weightier than seat system plus pilot.
    When occurs something that causes instability PWS return to vertical position not only because of weights but also because the hull helps it.
    It is important to have big difference of weights in order to turn faster the returning to natural position.
    In my opinion gyroscopic is needed if the natural position is not what we need. This is not the case.

    2. Balance
    The seat system with cardan absorves balance, not all but a big part.
    In small boats everybody feels balance.
    Another idea, consider that the hull as a sensor that permits it follows exactly the shape of the wave. In this case pilot doesn’t feel any balance; he is always at the same position. This can be done with electronics.

    3. Control
    Pilot can control position of the hull, speed and direction
    Position of the hull can be controlled with a motor, drive and a cable system.
    Speed can be controlled with motor, drive and, for example, propeller.
    Direction of the movement can be controlled with a rudder.
    It is critical when pilot starts because of inertia there is a trend to lean back. The solution is also control the direction of the propeller or jet around a perpendicular axis to movement plane.

    4. Speed
    My idea is more than 20 mph

    Best regards
     
  11. korvello
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    korvello Senior Member

    LUIS we now are getting some where or are we? ........ it appears you are making this thing to heavy and complicated ...........if one wanted a big buoy to sit on,fish from it ,cruise at 20 mph ,have a trailer to carry it and deploy ,i think it's called a PWC [ sorry couldn't resist,you set yourself for it]........on a more serious note i was hoping you where trying to make a self propelled hydrofoil or something where the buoy would be used at slow speed and at rest and the motor and some form of foil and rudder would control it ,you are loosing me here ........why don't you put the motor on the buoy if all you want is to drag a buoy on the water the motor could be in front of it and .......oh well here i go again .
     

    Attached Files:

  12. Luis Cunha
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    Luis Cunha Junior Member

    Hello Korvello,


    Thank you for your comments.
    A Jet Ski weights around 300 kg, to carry it you need a trailer, you can reach much more than 20 mph driving it, it has complex systems and people buys it. How do you explain this phenomenon?

    I would like and appreciate to receive comments from someone like a professor or experienced architect in order to confirm if you are right or not.

    Anyway and because I think this idea is good I will do a small model where each part has either the same density of full-scale or a scaled weight of the full scale ensuring the same centre of gravity for the model and full scale. This suggestion was done by Mr. Jorgen Jorde from LMG Marin (Jorgen, thanks very much! Great company, great people!)
     
  13. korvello
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    korvello Senior Member

    LUIS sorry just testing your idea !
    you're the one that mention that motor and suspended mechanism should weight more than buoy and pilot , are you going to find someone that weights 40 kg or do you intend to make this thing for adults; so let's say a normal person plus buoy would be what 85 kg [imagine how much one would have to weight to balance someone like WALRUS, and you tought a PWC was heavy ..:D :D . ] how are you going to carry your PWS around unless you carry plates like in weight lifting and just insert plates has needed or this will be only for bodybuilders ...............i like your idea and i hope a real engineer or professor has you say would say something ,i just think they have to much to loose by even commenting on it , unlike me [the silence speaks for itself]...............that's why i say make it light so one can carry in the back of the car,make the buoy come out of the water at speed there one could go fast and would also required balance and skill to drive the thing , then you'll have a real fun toy that anyone could take to the beach ..............has i said if it's just a self propelled buoy that weights a lot would that just be an exercise in futillity or do you think someone would real be interested in one?
     
  14. Guest625101138

    Guest625101138 Previous Member

    Luis
    You do not need a professor to determine the weaknesses of your design. You should be able to do the calculations yourself.

    Stability/Balancce/Weight
    Typical adult males that might be interested in using the device will weigh around 100kg. Seat, stand and controls will add another 15kg say. Your centre of bouyancy will be around 1.5m from the rider and seat CoG. The offsetting weight of the drive system will be about 0.6m from the CoB. So using moments the weight minus bouyancy of the drive will need to be:
    Drive Weight (less its bouyancy) = 115 * 1.5/0.6 = 287.5kg
    You now need to add the extra bouyancy of the drive. Could easily be 20 litres in volume so add another 20kg. You end up with a PWS weighing in at more than 307.5kg. We have not added any weight yet for the float. It will need to be quite large. You usually like to have 100% reserve bouyancy so it will need a volume of 600 litres. Not something you can fit in the back of a station wagon.

    Speed
    To do 20mph (8.9m/s) something of this proportion needs to plane so you will need to flatten and straighten the bottom of the float. We have a craft that weighs around 350kg with light weight construction. With a 100kg rider and lets say 20kg of nibbles/refreshments and fishing gear the total displacement will be 470kg. The simplest way to determine the required power is to calculate the drag as 1/8th of the total weight:
    Drag = 470/8 = 58.75 kg
    Power = 58.75kg * 9.8N/kgf * 8.9m/s = 5,124W
    You could assume a propeller efficiency of 70% so installed power will need to be 7.3kW or roughly 10HP.

    Design Development
    Since the required hull would be much larger in proportion than you have drawn it could be designed to have an elevated centre of roll (large KMT)and this would improve things dramatically - enable less weight in the drive and therefore reduce the required power. It would look more like a small flying saucer maybe 2m in diameter rather than a water buoy.

    If you want something more compact than a jet ski you have to get low in the hull. Have you seen the powered kayak here:
    http://www.youtube.com/watch?v=8aJhnkR_FF0
    Sitting high above the water means you need a big hull even if it has a weighted keel.

    Rick W.
     
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  15. Luis Cunha
    Joined: Sep 2007
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    Luis Cunha Junior Member

    Hello,

    Thanks to Rick Willoughby. Your comments were much appreciated.
    I think the main weaknesses of this concept are:

    1. Portability (weight and dimension)
    2. Hull design to reach speed and stability
    3. Starting up

    Considering the following ideas / comments of Rick Willoughby, Korvello and myself I think I can solve all above problems:

    1.a. Insufflate hull
    1.b. Easily assembly / disassembly

    2.a. Flatten and straighten the bottom of the float to turn possible higher speed
    2.b. New seat design (I’m still developing this idea)

    3.a. Direction of the propeller or jet around a perpendicular axis to movement plane due to start up issue (I need to think better about this).

    Soon I will revert.

    Luis
     
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