Most Efficient Boat Propulsion

Discussion in 'Sterndrives' started by tom kane, Dec 4, 2014.

  1. myark
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    myark Senior Member

    Wow, you do have a problem don't you, I feel sorry for you
     

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  2. myark
    Joined: Oct 2012
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    myark Senior Member

    Hi tom
    The Caracat designed by the late Bryan Jackson in Auckland who won the general publics open ocean launch races back in your day, as not only he came in first place year after year, he would have the best fuselage efficiency of any other boat and won that prize as well, this was because of his back end design on his cat acted like a whales tail or hydrofoil, that is attached below, and like your design no matter how much he proved the outstanding performance to the general boating traditionalist, they still refused to take note and tall poppied him.
    I showed Bryans my designs 10 years ago and he was overwhelmed that someone at last understood his theory even though he proved the design over and over which reminds me Bryans exact words you said to me some 20 years ago .
     

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  3. whitepointer23

    whitepointer23 Previous Member

    I don't really understand what you mean here . An outboard leg can trim in or out to alter boat trim in different conditions. Following sea trim nose up for running into back of swells. Head seas trim nose level to cut through waves. What are you saying. That this is wrong and only your drive can do it properly. And as others have said you can't run a sp prop submerged. Your solution is to use a 9 spd trans to overcome this and carrying different props. So with all that plus some sort of electronic sensor system to avoid obstacles it will end up more complicated than a leg or outboard.
     
  4. SamSam
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    SamSam Senior Member

    .

    The OP doesn't have much to do with the Cam.a.Propulsion system that Myark has shown in the last few posts. No electronics or mechanicals to automatically lift the shaft and slow the engine , no ski sponson steering. It seems it comes down to a drive not much different than this...

    [​IMG]

    http://www.fao.org//docrep/007/y5649e/y5649e00.htm

    Aside from any merits in the drive system, I can see where Tom's salesmanship might have been an impediment to public acceptance. If all questions about the undocumented claims in the advertising were dismissed as dribble, well, about the only people who would fall for the pitch would be real maroons.

    I can see where the system could have it's uses in a specialty situation, such as the the very interesting and handy looking folding barges/platforms that Myark makes, but it is too restricting for all purpose boating in that the boat itself has to be specifically built to match the drive system. You can flop an outboard on just about anything with no trouble, whereas the Cam.a.Propulsion system requires a specially built boat. In the end there doesn't look to be much performance difference between the two systems, but one of them has seen plenty of use with mountains of documented data and the other, not so much.
     
  5. myark
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    myark Senior Member

    I have seen in person Toms boat in action and been aboard, and yes it does what he claims and more so that's not an issue, also I can understand your idea of convenient boating, but to own a new 4 stroke outboards is $$$$$$$ a working class has trouble affording let alone to maintain cost or the devaluation he will suffer at resale.
    I prefer jet boats myself and others prefer sterndrives or direct drives for racing or skiing
    Yes the pivotal drive is well suited for the latest Myark folding trailer pontoon that the vehicle power is actually redirected into the pivotal propulsions allowing all the benefits as we know.
    Besides that I am working on a design with a motor of about 160hp placed in a smaller light twin hull similar to Bryan Jacksons Caracat design.
    The boat motor and trailer when in production is aimed at been worth what 160 hp 4 stroke outboard cost to buy alone, but most likely the pivotal drive will out preform because of the weight difference and hull shape, also can be used in shallow waters like a jet boat but with no weed problems or out at sea slicing through rough waters.
    The trailer is built into the hull that the removable torsion bar and arm, hubs and stubs are made from titanium, also the pivotal drive shaft can be made from titanium keeping every bit of weight down including maintenance and because the pivotal drive is raised into the hull it can be towed low to the ground.
    This craft has the all propose use like Toms but even more so because of the light weight and no trailer meaning can be beached launched and does not need boat ramps and DIY maintained and fuel efficient.

    Let’s say this is viable and I make the $ needed for such a project, the option for the buyer is to purchase an outboard without boat and trailer or for the same price a complete Myark high performance boat with built in trailer for the price of the 4 stroke outboard.
     
  6. tom kane
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    tom kane Senior Member

    The question was " Which propulsion system is the most efficient for all purpose boating".

    There has not been many suggestions yet, but check the dictionary to see what " Efficient " "Purpose " means.
     
  7. tom kane
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    tom kane Senior Member

    It would be nice if you could show me any most efficient hull (boat) design.
    But the question was "which propulsion system is most efficient for all purpose boating". Thank`s for contributing to this weird thread.
     
  8. tom kane
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    tom kane Senior Member

    You could pivot just the drive shaft instead of the whole drive unit, Pivotal drive. Just leave of the differential and fit a prop.
    Google Images ( Rear shaft drive for Autos) to see the many choices, this has been done for ever in autos so why not do the same in a boat, the system is well proven.
    Any handyman can build a pivotal drive for a boat and any competent marine workshop could build and install a Pivotal Drive in very short time.
     
  9. tom kane
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    tom kane Senior Member

    I am not trying to Patent anything on this thread. You could build a propulsion system for yourself with the ideas and things you would want and you think are best for your purpose. That is what I have done.

    Pivoting drive shaft have been around for years in rear wheel autos but no one thought to use the idea in boats don`t you think that is weird. Experts say you can not do it and do not no how to change a design simply for improvements and greater pleasure boating. Aircraft have folding landing gear now so why not take the idea to boat propulsion.
     
  10. tom kane
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    tom kane Senior Member

    You can easily fit an outboard on to a boat so that it can be quickly lifted I have tried that myself and it certainly is better than tilting the outboard backwards and much more convenient and works better going close to shore into shallows because the propeller works at a better horizontal angle.
    You can only lift a prop a small amount before thrust is lost.

    Tilting the outboard to work in the shallows is useless and with a bit of power on can push the back of the boat down if there is enough water above the prop like water surges. Keeping the water supply going to the motor needs modifications which is not easy for prolonged shallow water use.
     
  11. tom kane
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    tom kane Senior Member

    The Pivotal Drive is not much different to the diagram that is how the confusion comes in. The motor of the drive shown pivots with the drive which is no use with more powerful heavy motors and it is more convenient to have the motor soft rubber mounted and with C/V joint like conventional inboards.

    With Pivotal Drive thrust brgs and more reliable water seals are used. The Pivotal Drive is "Improvements to such drives" which were challenges to my Patent Application. Any handyman could build a drive like the one shown or a Pivotal Drive and be very happy with a versatile very efficient all purpose and simply propulsion. Thank`s for the input to this weird thread. No doubt more sophisticated pivoting drives will be will be built as someone sees a way to improve them.
     
  12. tom kane
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    tom kane Senior Member

    The only modification to a hull to to take a Pivotal Drive is a small slot in the transom and the bottom of the boat which is covered with a stainless steel cover in effect giving more strength as a stronger stern post.

    This slot can be used to slide in a Pivotal Drive of a variety of designs and even a water jet that can be adjusted up and down or a surface drive turbo drive.Mud boat drive also.
    You can choose between surface drive or sub-surface drive just by sliding in the drive of your choice.
    All of the performance data for different drives you can easily find.
    I am not making any claims about this drive or any other but asking "Which is the most efficient propulsion for all purpose boating". In the opinion of forum members.
     
  13. gonzo
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    gonzo Senior Member

    That was one long string of more of the same. Not a single verifiable datum.
     
  14. myark
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    myark Senior Member

    Hi Tom

    Thanks for sharing that inspiring variety of information about your pivotal drive system.
     

  15. jbergum
    Joined: Dec 2014
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    jbergum Junior Member

    Do not know what is the most efficient propulsion...., but if a pivotal surface drive with a single propeller is the second best, would a dual prop pivotal surface drive be the best?
     
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