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Trimarans and the BladeRunner...

Discussion in 'General Catamaran Discussion' started by catmando, Mar 3, 2005.

  1. YachtForums

    YachtForums Administrator

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    In water cornering at speed...

    In this photo, they appear to be exiting a turn. No way to determine what speed they are running, but the tunnels are fully saturated. In my mind, this begs the question of bow wave interaction with the sponsons and the turbulence created by the same. Water is being displaced upwards into the tunnels, which is then forced around and down the inside edges of the sponsons. This is mixed with a lot of air passing through the tunnels. My point is… considerable turbulence. Turbulence can (and does) induce drag.

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  2. YachtForums

    YachtForums Administrator

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    Side Profile Rendering…

    In the side profile rendering, the outriggers (the appropriate verbiage is “sponsons”), would not offer any buoyancy to the forward section of the hull. Given their narrow cross section, they would induce minimal drag and therefore may not offer a sufficient surface area to compensate for a hard oscillation that could result in a hook. (this is just theoretical conjecture).

    I can tell you this much… this hull configuration will turn very flat. This is one of the reasons I would expect it to be prone to “swapping-ends”. If 180-degree pivots are not a phenomenon this hull induces, than I expect it would make high speed turns like it’s on a rail… because these “sponsons” would create a longitudinal slot in the water that would become a leverage point from which the drives could pivot against. This is not likely to happen because the BladeRunner is using surface drives. These typically don’t offer the deflection (or turning radius) of conventional outboards and stern drives.

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  3. YachtForums

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  4. Codger

    Codger YF Wisdom Dept.

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    YachtForums
    Your point is well made.
    Here's the "But" :D
    1) I think that we'll have a solid answer one way or the other within 5 hours as to the design being correct or not.
    2) When I was young, and speed was more important than survival, we built all manner of craft that defied the "rules". Some worked, others didn't.

    Since you've already made the admission that you have a warped mind you should appreciate that sometimes what all the rules state won't work, indeed does.


    I wish I could see some visuals of what they are going through right now.
  5. AMG

    AMG YF Moderator

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    You are right, a couple of days ago I was following another trimaran Garbo III, sailing the Around Gotland Race. It was very calm conditions but still in the early morning tacking at about 15 knots, the centreboard broke and they had to go in to Gotland. All of this I was following from the GSM-transmitters plotting on the web.

    The funny thing was that after a couple of hours I could see my friends boat leaving the port at a speed of 132 knots!! After arriving at Sandhamn in record time I suspected and later got confirmed that he (and his GSM transponder) had been flying there with a Seaplane... :)

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  6. YachtForums

    YachtForums Administrator

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    So true! :)

    Yes, we will have an answer soon. I hope they do well, return home safe... and make my ramblings sound like the futile conjecture of a delirious administrator.

    Just trying to stir-up things up around here. ;)
  7. Codger

    Codger YF Wisdom Dept.

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    On the site; "The Royal Navy will be providing logistical and filming support throughout the record attempt and using this as an exercise in their "counter terrorism fast waterborne attack" programme!"

    I wonder if much of the video will be available? Seeing how the craft performs in the various conditions would be most interesting. 80mph in to 6 foot waves and the wave period varies quite a bit.
  8. Codger

    Codger YF Wisdom Dept.

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    It seems that when they hit stretches of open water the telemetry fails. Looking at the buoy information they are having quite a ride.
    Making 75mph on the water when it's dark for the length of time that they are doing it must be inducing major pucker factor.
  9. AMG

    AMG YF Moderator

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    "Update Sun 10th July - Round Britain Attempt Halted

    The attempt on the Round Britain Powerboat World Record halted at 01.03 hours today. The position of the boat was 50 miles south of Cape Wrath.

    Early on Saturday afternoon the boat hit an unknown object in the water during the second leg in the Irish Sea.

    The team made the first of a number of emergency repairs in Northern Ireland which enabled them to continue their progress around Britain. They made further efforts to repair the damage sustained during the fuel stop in the Kyle of Lochalsh.

    At this stage the team were on schedule to beat the existing world record of 31 hours by five hours 43 minutes.

    Unfortunately the damage proved more extensive than first thought and a reluctant decision was made to call off the attempt.

    The crew are all safe and well"
  10. Codger

    Codger YF Wisdom Dept.

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    What a shame. I was thinking of that as a possibility last night but didn't want to say it in case it might jinx things. With the nav capabilities they shouldn't have hit anything fixed but there is all kinds of crud floating around just about anywhere that you go these days.
  11. catmando

    catmando Senior Member

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    **** container ships. :mad: :mad: I'm going to call Ice Marine's American builder tomorrow to get an update.
  12. catmando

    catmando Senior Member

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    My boat does indeed turn very flat. I like it better than heeling over like V bottoms do. Some cats, like Skater, MTI, Jaguar and Nor-Tech, do lean inward in turns but not as severely as Vs. I trim in to slow the boat for turns. The boat only runs 70mph now, so I turn at all speeds up to that with no problems, even in 2-3' chop. I have flown the boat several times the last two weeks of testing and it flies very straight and true, much like the batboats. I haven't stuffed it yet(hope I never do).

    And yes Carl it is a "reverse three-point air-entrapment" hull. That's what Art Carlson calls them. He built all three of his 24' models with flat bottoms, but his 33' boats, of which five were built, had bottoms very similar to the Bladerunners. I have no idea what his deadrise is on those boats though.

    My boat has no compression in the tunnels like true cats do. The tunnels are the same height front to rear. It's just straight-through with the air.
  13. brian eiland

    brian eiland Senior Member

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    Sea Knife

    Very similar to this same description, does anybody remember a hull form termed "Sea Knife" by Peter Payne?? and subsequent larger versions proposed for the Navy. Several different full size prototypes were built and tested. One version was raced once I believe.

    Original patent #3,763,810
    Last edited: Aug 18, 2005
  14. catmando

    catmando Senior Member

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    Couple years ago I saw something like that in Washington, DC. Huge ship in a narrow channel so I assume it's a very deft handler. Looked similar to The Cat car ferry in Nova Stotia.
  15. brian eiland

    brian eiland Senior Member

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    I don't think that's what I had in mind. Would you be thinking of another RV Triton prototype warship??
    http://www.naval-technology.com/projects/trimaran/trimaran7.html

    Peter Payne was a very learned mathmatican who had a very real interest in boats as well as other subjects. His attempts to define planing and other hydrodynamic phenomena mathmatically is difficult reading for most of us, but he made very real test on actual prototype vessels to confirm some of his theory.

    To quote a web reference,"Another type of Payne high speed boat achieves results in a different way. The SeaKnife hull form is a supercritical planing hull that cuts through waves instead of riding over them. This reduces the vertical pounding accelerations typical of conventional planing hulls by a factor of more than ten. There are a number of SeaKnife boats in operation and on the drawing boards. Designs include sport and racing boats, and military patrol boats. Another planing hull form is the WaveStrider, which has been produced as a 24-foot boat for the Navy, and is in production as a high speed ferry. (The stealth boat that appears in the new James Bond movie "Tomorrow Never Dies" is a WaveStrider.) He also developed the Air Lubricated Planing Hull (ALPH). A boat of this type is the Hydrotrac, noted as being the world's fastest production boat for a given power. All of his boat designs were tested in the Chesapeake Bay, near Annapolis, and the nearby Severn and Magothy Rivers. High speed planing hull theory receives a detailed presentation in Peter's book, Design of High Speed Boats, Volume 1: Planing. His computer program, BOAT3D, is used by many to model and design high speed boats."


    I will post some pictures sometime near future when I receive something presentable. I happen to have been in the Chesapeake area when he was conducting some of his early test on SeaKnife and I was also working with the Navy at the time. I didn't pay much attention to his 'far out' hull designs at the time, but I recently sought to go back and look at his concepts again as a result of both Bladerunner's work and Payne's concept. Mr Payne passed away a few years ago and I am talking with his widow and his son.

    I think a few on this forum subject will find the material interesting. I'm on holiday away from my computer so I can't access the few photos and the patent reference at this time. I'll find some photos eventually. I hope to see yours Catmando
  16. brian eiland

    brian eiland Senior Member

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  17. JonS

    JonS Senior Member

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    :eek: Wo! Could that image be any bigger!?! A little resizing needed me thinks! :rolleyes:

    Edit: and just as i was typing that msg, it was done! It was like magic!
  18. brian eiland

    brian eiland Senior Member

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    I'm still a bit 'computer challenged' at times, and particularly while working on a stranger's computer here in Nova Scotia on holiday.
  19. catmando

    catmando Senior Member

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    Yes, too much going on with that bottom. :rolleyes: No air pack or very little in those "tunnels". Deadrise must be close to 0*. :D That would do more than jar teeth fo shizzle. :D
  20. catmando

    catmando Senior Member

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    This is from the website. These men have spent thousands of man-hours designing and testing this hullform.

    Bladerunner – a unique philosophy.

    Bladerunner is an ‘Air entrapment monohull’ or AEM

    Pioneered by ICE Marine the AEM is radically different to a conventional monohull, with dramatic twin tunnels that flare out either side of the extremely slender twin stepped hull finishing with sharp knife like sponsons at the sides.

    This unique combination gives a Bladerunner phenomenal aerodynamic lift, which improves performance and significantly softens the ride over conventional monohulls by compressing the air inside the tunnels adding a cushioning effect. A further advantage is that the centre of lift is located much further aft than a comparative high performance catamaran, providing a safer and more level ride in rough seas. The sharp keels of a Bladerunner’s sponsons cut effortlessly through the waves, which is a stark contrast to the wide flat chines of a conventional monohull that impact hard on the surface of the water. They also form the outer walls of the tunnels, which is essential for air compression and the resulting aerodynamic lift.

    The Bladerunner is kept stable and level in a straight line and when turning by a combination of the sharp keels and the pressurised air in the tunnels. These same sharp keels also provide superior directional stability to avoid any unforeseen sudden changes in direction (hooking) to the left or right that high-speed monohulls and catamarans are prone to. The net result of all this is a quicker, safer and more efficient hull that has superb rough water capabilities with inherent soft riding characteristics.

    If this leading-edge design technology sounds amazing on paper, you only have to experience a Bladerunner for a short time to understand what it means in reality.