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Front, Mid & Rear Rudders?

Discussion in 'Technical Discussion' started by sunray09, Mar 31, 2011.

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  1. sunray09

    sunray09 New Member

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    Can anyone tell me if there has been any research done on with small rudders on the bow of a vessel along with the traditional placement?
    To my mind a very small retractable rudder at the bow might give a boat the ability to turn quite quickly which in some situations might be an asset.
    In a large tonnage ship that takes miles to stop and miles to turn..if you could add a small bow rudder that would help turn the ship in an emergency and still keep the stresses in limits..it seems to me it would be a general benefit to maritime safety...the ability to make the ultimate J turn.
    I cant help but think that if the rudder or tab was sized correctly it might afford a benefit to boats.
    In todays computer age....the front rudder could be independently controlled giving you the ability to cross control like an aircraft in a slip configuration.

    I know the stress placed(force moment) on a vessel moving quickly off axis would probably be great..not to mention upsetting the China..and passenger comfort but the ability to change course in a boat length or two..(computers could change the amount of front rudder available depending on speed) to keep things within sensible limits. We have bow and stern thrusters so why not small retractable bow rudder as well?

    Since I am throwing out wild ideas today....how about a small computer controlled airfoil wing on the bow of high speed racing cats.
    It stays stowed on the bow until sensors recognize a blow over about to happen and then it POPS UP providing aerodynamic negative lift pushing the bow down preventing blow over. Like an air bag...only its a wing capable of being operated multiple times in a race situation.

    On lots of yachts it seems to me..there is space between the fly deck and the salon below..to have an INSERT which contains a retractable extension to the deck above. Why? To give you an expanded sun deck cantilevered over the decks below allows room for a temp flight deck etc.
    Retracted you would not know the deck extension existed if it was done right.

    So there it is all of my imagination and stupidity in one place...have fun
  2. AMG

    AMG YF Moderator

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    Hi, I have seen all of your ideas in reality...:) Regarding adjustable air-foils on racing boats, they were not allowed by UIM after a few accidents in the late sixties. I don't know if this is lifted today when electronics are faster...
  3. sunray09

    sunray09 New Member

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    Cool

    Thanks...it means...I am not an original thinker!
    Someone else has all ready engineered the cost benefit ratios and figured out that bow thrusters are better probably...less drag etc.
    Thanks! Its nice to get all my wondering out in one post..now I can go back to quietly lurking...until that lottery ticket turns up!
  4. GFC

    GFC Senior Member

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    AMG, I could be wrong but it's my understanding that the Unlimited Hydros have a wing that is supposed to do just that specific job. I did a google search but couldn't find anything that's current about moveable airfoils.

    I believe they are used extensively on the Unlimiteds and the angle of the airfoil is controlled by an onboard computer. When it senses the bow rising (as in the start of a blow over) it changes the angle of the airfoil to decrease the lift generated by the hull design and bring the bow back down.
  5. AMG

    AMG YF Moderator

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    Yes, it may be possible that national rules, like APBA are different from the international rules.
  6. NYCAP123

    NYCAP123 Senior Member

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    Several types of slowspeed ferries use bow & stern rudders to help maneuverability. Used to run an old garbage boat (converted ferry) with them. Can't imagine using them on any kind of fast boat though.
  7. sunray09

    sunray09 New Member

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    I think more like a small tab..than a full size rudder..or a retractable tab that can vary its surface area for speed..Large area for low speed authority,and then retracted to provide a smaller surface at speed.

    I was thinking of the OCEAN CATS with the large broad fore deck..with a built in wing...if the BOW comes up too high too fast the WING POPS UP from the deck to provide down force and bring the bow down and then retracts..
    Might stop the blow over but stuff the bow into a wave...such is life in my imagination. Rudders on both end of a ferry makes sense.!
    Thanks for responding!
  8. Marmot

    Marmot Senior Member

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    Don't most of those boats pitchpole with the bow down? And it's not like you have a strong relative wind over the deck at an angle you could do much with anyway, not like a hydroplane.
  9. sunray09

    sunray09 New Member

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    I have seen them pitchpole but I have also seen the BOW come WAY UP when running through some seas...having a computer controlled wing that could correct an attitude problem before it became an EVENT might only be rarely neccessary..so they have not engineered a solution for it.

    Modern airfoil design is such that you can make a wing produce effective lift at very low speeds..Ocean cats...move along fast enough that if an airfoil was extended into the airflow down force would be produced.
    Its not something that would not require modelling...if you make the wing too big it would stuff the bow...not optimal...
    The idea is the sensors figure out how much time the wing needs to be extended for and at what angle...and then retract...it would be moving up and down...in a race to help balance out the running attitude as the boat moved through the air..preventing excessive vertical movement of the bow..beyond the ability of the drives and trim tabs to compensate for..
    It should run as flat and true as a cruise missile no matter the sea state.
    Of course you should be able to disable the system if you want to also..
    In my minds eye I see a wing that is capable of vertical extension from the deck and in an emergency situation capable of extending horizontally providing a wide wing to provide maximum surface area and down force .
    All I want the wing to do..is stop the Boat from Blowing over...keep it running in a level attitude...no matter what the sea state..and how long of a jump its taking over the waves.
    As soon as the bow rotates up to a certain point...you have no aerodynamic control anyway...the goal is to keep things below that using the wing in conjunction with drive trim and trim tabs etc..
  10. YachtForums

    YachtForums Administrator

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    A canard on a boat? What a cunning idea! Good for you for thinking outside the flight envelope. ;)

    Attached Files:

  11. sunray09

    sunray09 New Member

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    Wow

    That looks so real, but its a mono hull...with wings!!
    Who did it...which racing team? That looks really neat...no retraction mechanism
    so you have the wing in play all the time...that is the most amazing image.
    Thanks!
  12. YachtForums

    YachtForums Administrator

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    This wasn't a race boat. It was designed by one of my colleagues as a POC boat for a defense contract in the late 1980's. The canard is active.
  13. sunray09

    sunray09 New Member

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    The Whole Story Please

    POC? and you don't get off that easy..show me an amazing image...and then say nothing about it!! What is a P O C and what was this called...are there any video's of this boat running.? I want to know as much as you can tell me about this...an active canard on a mono hull! You can not tease me like that with no name I can't google anything !! So take some time sit right down and spill the beans....I doubt there is anyone else who can tell me the story of that picture and how it came to be....So in your own time....give me the 5Ws
    Who What When Where Why and How did this thing work out?
    Thanks in advance...and oh...great job on the website...I love it...
    If I had the money I would have the Hatteras people build me a hull for a Leonardo 98....yes it would be heavy....but it would still look goooood!!
  14. YachtForums

    YachtForums Administrator

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    Proof Of Concept.