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Trimarans and the BladeRunner...

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

  1. KCook

    KCook Senior Member

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    I suspect putting rocker in the keel of the sponsons makes them less resistant to steering forces. The boat's gotta turn someday!

    Kelly
  2. Brian

    Brian Senior Member

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  3. Lorne Campbell

    Lorne Campbell New Member

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    True about the rocker but I wasn't suggesting taking the sponsons all the way back - even the Bladerunner's sponsons stop forward of the transom these days. A compromise between turning and directional stability.

    What a labour of love Kenau seems to have been - wonderful sequence of pictures. I wish I was as good at the CAD, too! What is your opinion on the efficiency of the pod drive?
  4. brian eiland

    brian eiland Senior Member

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    Yes the std gearbox would be used this case, as you also need the gear reductions. The chain/belt unit is there just to transmit the power in a vertical manner from engine to prop, and could have the provision to do it in a duo-prop form, as well as a single prop arrangement, and as a pusher or puller form.


    I have presented the possiblity of building such a unit to several different clients who have yet to take me up on the idea. They like it but are still considering the vessel as a whole. I have an outfit in Thailand that could likely build it.
  5. alexmeldrummr4

    alexmeldrummr4 New Member

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    Regarding the Sea Knife

    I was privy to the Navy plans and special R&D with the original secret KNIFE BOAT PROJECT in 1981. It was a fast attack PT style boat that could be lauched rapidly to persue enemy subs. The design called for two deck mounted torpedoes, a 50 cal gun, and room for three men. Design specs also outlined top speed to be no less than 100 knots in a sea state five. It's a appears the that the Sea Knife project was swallowed up by the stealth boat's design team. Too bad, they were onto something with that boat.

    Peter Payne's work is genius. He and Bill Lear must be related, their styles are so very similar.
  6. brian eiland

    brian eiland Senior Member

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    Seeing as how Alexmeldrummer revived this subject thread from 2007 to 2009, I guess it can't hurt to revise my last posting on chain/belt drives.

    Brian had replied:
    Yes the std gearbox would be used this case, as you also need the gear reductions. The chain/belt unit is there just to transmit the power in a vertical manner from engine to prop, and could have the provision to do it in a duo-prop form, as well as a single prop arrangement, and as a pusher or puller form.


    Brian had replied Dec 2007:
    I have presented the possiblity of building such a unit to several different clients who have yet to take me up on the idea. They like it but are still considering the vessel as a whole. I have an outfit in Thailand that could likely build it.
    _____________________________________________________
    I'm looking at this possiblity again. Just this week began corresponding with a Gates belt designer on a carbon fiber idea in the 150 HP range.
  7. brian eiland

    brian eiland Senior Member

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    SeaKnife, double play

    How strange...within a period of a week here we got messages from two fellows involved with the SeaKnife project. The second message came to my private email, and I inquired as to whether the two were the same person...no was the answer. So I'll post his message here as he may not be interested in participating in the forum, but his comments are worth repeating


    I thought that last sentence was interesting
  8. brian eiland

    brian eiland Senior Member

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  9. brian eiland

    brian eiland Senior Member

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    Littoral Combat Ship #2

    Here are some recent photos of the LCS 2 (to be USS) Independence . She’s at 43 knots here running at half power. NOTE the absence of a bow wave.

    Turns tightly, also; allegedly this also was done at 43 knots...and from the look of the small bow wave, she’s still in the turn.

    And then we have the massive helo deck big enough for a CH-53. Last time I talked with the SURFPAC guys years ago.THIS was the LCS they liked because of the huge storage capacity under that flight deck and the size of the flight deck.

    Note that there is very little spreading wake. In fact, it does not look like a wake at all, just foamy water from the water jets. Somehow, at 40 knots,you’d think there'd be more wake

    But she has one drawback, she’s strange looking but aerodynamically designed, is this beginning of a new design in ships?

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  10. KCook

    KCook Senior Member

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    Ok, I'm amazed such fine hulls would turn well ....
  11. brian eiland

    brian eiland Senior Member

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    Iran to produce armed copies of Bladerunner 51

    By IBI Magazine

    The Iranian Navy has produced a replica of the British-built Bladerunner 51 speedboat and is intending to mass-produce and arm them with missiles and torpedoes as it builds its military presence in the Strait of Hormuz.

    General Ali Fadavi of the Iranian Revolutionary Guards (IRG) told global news agency AFP: "The Bladerunner is a British ship that holds the world speed record. We got a copy [on which] we made some changes so it can launch missiles and torpedoes." Fadavi was speaking during a recent ceremony that marked the delivery to the IRG of 12 other speedboats equipped with missiles and torpedoes.

    Built by Britain's ICE Marine, the 15.5m Bladerunner 51 is one of the fastest high-performance sportsboats in production in the world today. The BR-51 Bradstone Challenger smashed the Round Britain World Record in 1995 when it completed the 1,691-mile circumnavigation in just 27 hours and 10 minutes at an average speed of 53.5kt (61.5mph).

    Jeremy Watts, ICE Marine founder and company director, told IBI today: "We are very concerned and disappointed to learn of the Iranian plans to copy our Bladerunner 51 design and to potentially use it for military gain. This news confirms our initial fears when first hearing they managed to acquire the 2005 Round Britain Record breaking Bladerunner 51 called 'Bradstone Challenger' early in 2009.

    "Following the successful record bid, Bradstone Challenger had been sold on and converted to leisure use, spending two seasons cruising the Mediterranean under private ownership. Bradstone was then put up for sale by the owner in 2008 where it was purchased by a South African dealer, who was later found to be acting on behalf of the Iranians and who used a variety of smoke screen tactics to cover up the eventual destination and Iranian ownership, claiming the boat was intended for a wealthy South African businessman. The boat was reportedly shipped to South Africa but was then reloaded onto a transporter and shipped onto Iran.

    "Although Bladerunner development has progressed significantly since the design of the Bradstone Challenger, it is nonetheless galling to hear it may be copied and used in this way and without our consent following many years of hard work, cost and development. It is relatively easy to make a copy of a hull when you have a boat to mould from, however, to engineer and set up the boats correctly without prior experience of this type of craft is certainly more difficult."
  12. brian eiland

    brian eiland Senior Member

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  13. brian eiland

    brian eiland Senior Member

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    Still unanswered...the considerable difference in the length of those outer sponsons (hulls). I imagine the longer ones are better in terms of speed, but I wonder how they might contribute to a diagonal stability problem in a heavy following sea (running down big ocean waves)??

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  14. brian eiland

    brian eiland Senior Member

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    Trimaran Hull Design for Combat Ships

    I ran across this site, and excerpted this portion of the discussion. This might account for a rejection of the tri-hull concept, even while it looks so advantageous in its operational goals.

    LOTS of illustrations also!
    http://navy-matters.beedall.com/fsc-pre2005.htm

    Future Surface Combatant (FSC) - until late 2004

    One design option for the FSC is a revolutionary trimaran hull concept with a slender main hull and two outriggers. There are numerous theoretical advantages of a trimaran hull form with a slender central hull with outriggers over conventional mono-hulls:

    •Reduced hull resistance at higher speeds resulting in typically 18-20% less installed power for an escort sized vessel required to achieve 28 knots
    •Wide range of propulsion options
    •Greater fuel economy
    •Improved stability and reduced motion.
    •Increased directional stability.
    •Top weight growth margins are greater. There are significant additional stability benefits in the area of growth margins. This will allow equipment upgrades during the life of the ship to be easily accommodated .
    •Increased deck area (up to 40 per cent) on 1 and 2 decks for a given tonnage, offering more space for hangars, helicopter operation and weapons. Some of the greatest advantages for the trimaran comes from the improved effectiveness of the whole ship design afforded by this very large deck area.
    •Improved sea keeping performance at higher speeds, operational in higher sea states.
    •Increased stealth - potential for reductions in radar cross section and infrared signatures. A reduction in heat signature could be gained be exhausting between the side hulls rather than conventional main structure funnelling.
    •The side hulls can be utilised for configuring a multiline towed array sonar.
    The Ministry of Defence has been sponsoring research in to triple hulled ships since the late 1980's. Importantly, work by QinetiQ (formerly DERA), UCL and Vosper Thornycroft has now confirmed that a trimaran hull form does indeed reduce drag by about 20 percent at high speeds compared to a single hull. The lower resistance will permit higher speeds to be achieved, or a reduced machinery fit leading to lower through-life costs.

    Increases in size and to some degree location of the superstructure can be easily accommodated without affecting the ship's stability. This is because of the de-coupling of the main hull beam from the required stability. The required stability can be obtained by adjusting the size and distance from the main hull to the side hulls with little impact on drag and weight. This will allow heavy equipment such as large radars to be fitted more easily than could be achieved with a monohull.

    The outriggers make the ship more stable and give it a larger flight deck, which can be moved away from the stern and nearer amidships, allowing helicopters to operate under a wider range of sea conditions. It is possible that the wide upper deck will lead to the provision of a second hangar which could be used for other service helicopters such as the Apache for land attack, support or relief operations. Optional side-hull propulsion in the outriggers makes the ship more manoeuvrable. And if the ship does take a hit, the outriggers protect the inner hull, where the main power plant is contained. Survivability in general from weapons strikes will potentially be greatly improved.

    However, the trimaran approach does also have several possible disadvantages when compared with a mono-hull approach for FSC:

    •the very long and wide hull will make a trimaran FSC too large to fit in to existing escort refit facilities and dry docks, necessitating expensive redevelopment of these.
    •worldwide, there is no experience with designing, building and operating large steel trimaran ships (other than the small RV Triton).
    •increased and unusual structural stresses may present significant design challenges and technical risks
    •possibly higher construction costs.
    •reduced stealth - radar, noise and wake signatures may actually increase in practice
    •reduced internal hull volume for a given tonnage, so less room for accommodation, VLS cells, fuel and stores, etc.
    •instability if an outrigger is lost or flooded.
    These disadvantages when combined with the risks and doubts inherent with any major revolution in naval design may yet prove too severe, and a mono hull form adopted for FSC.

    Originally a hull displacement of about 5-6,000 tonnes was expected for a trimaran FSC, but this seems to have crept upwards. Concept studies have apparently considered displacements as high as 14,000 tonnes and a 9000 tonnes design was the baseline configuration in early 2003.


    ...further down in the discussions:
    RV TRITON
    A joint report written by senior USN and RN officers in early 2002 on the Triton trials was positively glowing about the results. Apparently all the hoped for trimaran virtues were confirmed – economy, sea-worthiness and comfort, etc. The only downsides highlighted were the predictable impact on berthing and dry-docking. The results will be included in the Staff Requirement submission for the FSC.
  15. brian eiland

    brian eiland Senior Member

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    Trimaran Warships

    "Catamaran and trimaran hull designs are faster, more stable in high sea states, have similar internal volumes as single-hull ships, and are more fuel-efficient than conventional hull designs. In addition, a trimaran's outriggers add stand-off range to the center hull, where vital equipment (computers, propulsion, living spaces) would be located. This stand-off range would make the ship more resistant to damage from attack."

    http://www.g2mil.com/trimaran.htm

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  16. brian eiland

    brian eiland Senior Member

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    http://www.motorship.com/news101/triton-trials-trimaran-form

    "The result is a main hull having a round bilge shape with underwater sections approaching semi-circular shape amidships. A gentle rise of the bottom lines aft leads to a counter-stern transom with minimal immersion. The side hulls are of multi-chine design on the outboard face with a flat plain inboard face for ease of manufacture.
    The demonstrator was built at two thirds the size of a full-scale warship"


    "The trimaran design is faster and more manoeuvrable than an equivalent sized mono-hulled craft, says QinetiQ. It adds that Triton has proved that the triple-hull design offers a reduction in drag of 20% compared to a conventional mono-hull vessel"


    "The extensive sea trials have been undertaken in a wide range of weather conditions up to a sea state of 7 to 8 with the ship sailing at short notice to stormy sea areas around Ireland, south Iceland and off the Norwegian coast. Using a star trajectory pattern the trimaran was subjected to every conceivable wave pattern. QinetiQ says there were very few instances where it shipped green seas over the bow. Special attention was paid to the slamming effects under the decks linking the hulls. QinetiQ says the vessel?s handling capabilities have validated the designers? claims by confirming the naval architectural performance."


    " Bob Short, QinetiQ?s RV Triton programme manager, says that Triton has already gone a long way to validating earlier research and has demonstrated the considerable benefits associated with triple-hulled vessels. He is also quietly confident that trimarans have a huge potential commercial application worldwide and the agreement with Vosper Thornycroft strengthens the UK?s position as a world leader in trimaran technology.
    Ultimately, however, one has to recognise that a fundamentally conservative industry such as shipping will take some convincing before it will commit hard cash to a new hull type"
  17. brian eiland

    brian eiland Senior Member

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  18. brian eiland

    brian eiland Senior Member

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    ‘Disappearing’ Warship

    Austal, America’s newest warship-builder, is still scrambling to recover from the late-June revelation that the USS Independence, the Littoral Combat Ship it just built for the U.S. Navy, is “aggressively” disintegrating.


    The 418-foot-long Independence (pictured) is slowly disappearing due to a process known as “galvanic corrosion,” where electrical current passes through a join between two different metals — in this case aluminum and steel — causing one of them to break down at the molecular level. Independence will be spending some time in San Diego for repairs.

    The Navy has systems for dealing with galvanic corrosion, but did not include them in Independence’s design. And early on neither Austal nor General Dynamics seemed terribly alarmed at the omission. It’s possible they planned to control corrosion with rigorous, post-delivery maintenance procedures.

    ...more here:
    http://www.wired.com/dangerroom/2011/07/plenty-of-blame-to-go-around-for-disappearing-warship/

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  19. BMcF

    BMcF Senior Member

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    Ironic..isn't it? The USN/ONR Sea Fighter catamaran was designed and built by experienced aluminum high-speed ship folks from US and UK and was launched in '03 with an extensive active coorosion protection system installed. OK..it was not perfect right out of the box and its total capacity had to be upgraded within a year after launch. But still....give me a break on the "we're not stupid on purpose..really" factor, Navy people.
  20. brian eiland

    brian eiland Senior Member

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    I was looking back thru some more recent articles, pics, etc that have become available about Payne's Sea Knife vessel,....

    ...and I ran across this posting on WarBoats.org "The Sad Saga of the Sea Brick". Looking at the photo that appeared with the article I was once again reminded of the "M Ship" that I had also made a posting about.
    Sea Brick,ps.jpg
    Sea Brick

    ...excerpts
    .......number of files spread out on Mr. Mac’s desk in the back of the OP’s office. There were four designs, but the one which caught my eye was the Sea Knife.

    The other contenders for what we in Special Boat Squadron termed the “PBM” contract were far less dramatic, a rather blocky semi-surface effect boats..

    I asked Mr. Mac and Keith which design they thought was the front runner, hoping that they would say that spectacular Sea Knife, but I was shocked when Mr. Mac replied, “Probably one of the two conventional hulls.” Hey we were in Spec War (Naval Special Warfare), surely we would be getting the latest and greatest, most futuristic design. Little did I realize what the true situation with respect to procurement in Spec War was at the time and where we sat in the Naval hierarchy of the day

    Needless to say, we all were very surprised months later, when we learned through the grapevine at Special Boat Squadron that the semi-surface effect craft design was chosen for the PBM contract. It not only flew in the face of my Sea Knife daydreams, but of the more sage and sound predictions of Mr. Mac and Keith Johnson as well as my many other shipmates who were putting their money on the conventional deep V’s. Another fact at the time which did not register then was Rohr Marine Industries (RMI) of National City, California, a local company with no experience in patrol boat design and construction, was awarded the contract.

    ....more on this story in the weblinked story from Warboats.org (interesting site)

    This new vessel was eventually nick named the 'Sea Brick" in stark contrast to her semi-offical name of "Sea Viking"

    Why is it I get this same feeling of 'who is making these decisions', and 'what lobbyist/money are driving these decisions when I review the Navy's M-ship project, and the Navy's apparent choice of the more conventional monohull Littorial ship design over the tri-hull design.

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