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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Sun Jan 02, 2011 11:04 am Post subject: Trying something new |
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Hope to have it on the water in a month!
gregoryboice@yahoo.com
23 foot Air Entrapment Mono-hull
Some history and Design Goals-
Having some experience in Marathon River Jet Boat Racing I am of the opinion that Eagle Racing in Canada has for years built by far the
best hull ever built for this purpose, this includes the step-tec hull in the SBFX class and the tunnels in all upper classes. Therefore my goal is to use the Eagle hull as a measuring stick, make significant changes and improve upon it's performance. Any and all design differences should be compared to the Eagle hull as a baseline and I will attempt to explain the reasoning behind the differences.
Weight- This is kind of where it all started for me, I am a big person and my weight is always a disadvantage especially in the lower HP classes I raced in. Generally, reduce the weight and you will go faster! My problem was Eagle, using a great design and fabrication techniques had already built lite weight models to the very edge of adequate structural integrity. In fact with some models the hull skin/plates were so thin/lite wt. That impact with nothing but water, big waves would result in pressure dents and some times major hull damage. So it would be impossible to simply take this same design and use lighter thinner metal. No solution here but start with a blank page and come up with a design that could do this.
I believe I have accomplished this goal, this hull is 23 feet long and weighs 380 pounds. This was accomplished primarily through reducing metal thickness and internal members and made possible by complete reorientation of the hull side and bottom plates, both in there shape and there orientation to the forces that act on and impact them. For example, in the new hull, the side plates are pretty much totally parallel to the direction the the boat is traveling, unlike the Eagle where in the bow area the sides wrap around to the forward most point of the bow and are exposed to fairly direct impact with waves/water. Like the side plates, the tunnels on this hull, are a constant radius without need of support except in the keel and chine. The more heavily reinforced center keel area will see the greatest exposure. A major difference here as compared to the Eagle, this hull has much less surface area both in size and orientation to react to impact with waves/water. The goal is to have just enough surface to provide adequate hydrodynamic lift/flotation to insure the bow does not “dive in” , not a good thing! But yet not have so much surface area that it “over reacts” as in, hit a wave and the bow goes flying! This is especially a problem with the Eagle where the center of gravity in the hull is so far back, lift in the bow, weight in the transom equals no longitudinal stability and a wild ride.
Design a boat that handled “big water” better-
It was also a goal to not only pack my butt faster but to also pack it further forward in the hull. A longer boat is more stable, no question and that's why this thing is 23' but more important to longitudinal stability is the relationship of Center of Lift (C.L.) and Center of Gravity (C.G.). In the Eagle hull the C.L is very far forward, even further now with the use of the new canard wings and the C.G. Is very far back, like less than 5 feet forward of the transom. This is of course all aimed at getting the boat out of the water and a necessary goal, after all water drag is 800 times more than air drag, if you want to go fast you have to get it out of the water, simple as that!
Ideally for the best longitudinal stability the C.G. Would be forward of the C.L. Just like in an airplane where the tail wing is actually producing a down force pivoting on the forward C.G. And holding the nose UP. We can't achieve that in a boat we want to “fly” but I have moved the C.L. much, much further back and the C.G. Much further forward and this hull will be much more stable and run rough water faster!
The new hull is most accurately described as a “Air Entrapment Mono-hull”. It is not a pickle fork or a tunnel hull or a tri hull or a conventional mono-hull. The design is intended to “operate in ground effect” by trapping and compressing air very close to the surface of the water substantial lift will be generated (nearly 40% more) yet at the same time, unlike the Eagle hulls the lift is very close to the transom and the hull has very little wetted surface. Overall this hull will have substantially more aerodynamic lift. Unlike the Eagle the sponsoms will not be wet except in hard turns. Since we rarely race in a straight line it is important to hold speed in a turn, this hull will do this because wetted surface will only increase significantly in very hard turns, even then much less than the Eagle. Also much effort has gone into orienting hull surfaces to deflect water not carry it across additional surface as does a conventional bow and chine design. This will be a very dry hull!
Air drag- Since we are mostly out of the water air drag becomes an important factor. It is truly amazing the speeds of the Eagle boats today and the many refinements over the years netting unbelievable speeds for a given horse power. Since air drag increases at the square of speed the new hull design will be much more aerodynamically efficient and will have a fraction of the overall air drag compared to the Eagle hull. Unlike the Eagle, where air is deflected in many directions or moved out of the way and a hole is bored, the new hull will move almost no air that is not creating lift exactly where it is needed. On the balance a huge plus.
The hull has a single 65 Gal. fuel tank mounted on center line just behind the driver and navigator seated in tandem not side by side. With all weight on center line the hull roll response will be much quicker and without resistance. This hull also has a water/vapor tight bulkhead just behind the cockpit completely separating the fuel/ engine compartment from the forward hull. An automatic fire suppression system will be installed in the engine compartment as well as passive and electric ventilation.
Greg Boice
gregoryboice@yahoo.com
(702)378-4208
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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Sun Jan 02, 2011 11:16 am Post subject: more pics |
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trying to add more pics
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Arthur Outlaw Eagle Admin
Joined: 28 Oct 2006 Posts: 1654 Location: On the rocks
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Posted: Sun Jan 02, 2011 11:19 am Post subject: |
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Holy chit BATMAN!
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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Sun Jan 02, 2011 11:23 am Post subject: more |
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more
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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Sun Jan 02, 2011 11:31 am Post subject: more |
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more
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rlnah2285
Joined: 20 Mar 2009 Posts: 12
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Posted: Sun Jan 02, 2011 11:53 am Post subject: |
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That thing looks fast! Definetly some great talent and time taken to create that work of art. I like how everything is hand fabbed and engineered!
My guess is that your going to be hitting closer to 100 mph or so? You will have to post some speed results once your done.
Great Job!
_________________ Hmmm.... well that was fun, lets try to see if that goes any faster yet! |
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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Sun Jan 02, 2011 12:25 pm Post subject: intake |
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Also built our own intake we feel will have some advantages!
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RPM
Joined: 17 Dec 2006 Posts: 189 Location: Nechako
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Posted: Sun Jan 02, 2011 1:06 pm Post subject: |
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to just call that something new is an understatement ! that's a freakin radical display of your obvious talents and imagination good luck with your project
_________________ Rick's Precision Machine
Prince George B.C.
Machining - Welding - Repairs |
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RChadwick
Joined: 04 Sep 2005 Posts: 21
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Posted: Sun Jan 02, 2011 2:08 pm Post subject: |
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innovative design but will be judged by results,really thinking outside the box.
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hellsgate
Joined: 07 Oct 2009 Posts: 26 Location: Clarkston, WA
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Posted: Sun Jan 02, 2011 7:00 pm Post subject: |
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Congrats on your hard work, Greg! Looking forward to live-action videos. What engine/class? BTW, you're not alone in making a bold design statement... your gullwing, my radical new Falcon hull, and JL's 'project' should turn a few heads in the upcoming seasons. Nice job!
_________________ Roads? Where we're going, we don't need roads. |
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DIGGINSWEATINSWEARIN
Joined: 02 Nov 2010 Posts: 47 Location: Deroche B.C.
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Posted: Sun Jan 02, 2011 7:50 pm Post subject: |
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Wow, that is freakin insane, love the oldworld craftsmanship, Dude you gots skills!!!
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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Sun Jan 02, 2011 8:58 pm Post subject: THX |
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Thanks for the comments, the boat has a CT525 and will be running in the CX class for the 2011 Canadian Worlds!
I have confiedence in the design and think it will do as expected, but until it's on the water and proves itself it's just a new idea!
_________________ Hasta La Vista Baby |
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DOC
Joined: 17 Jun 2005 Posts: 329 Location: Whitecourt
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Posted: Sun Jan 02, 2011 11:14 pm Post subject: |
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Thats quite a lookin unit, look forward to seein it in whitecourt. Good luck.
_________________ HANG ON NUTLICKER !! |
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Dale
Joined: 10 Oct 2005 Posts: 173
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Posted: Mon Jan 03, 2011 10:48 am Post subject: |
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looks good Greg. very nice craftsmanship. can't wait to see it in the worlds. are you going to Riggings??
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greg b
Joined: 15 Apr 2007 Posts: 75 Location: Clarkston Wa.
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Posted: Mon Jan 03, 2011 11:00 am Post subject: Riggins |
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Thanks Dale! My two all time favorites are the circuit course in Whitcourt and Riggins so yes I would love to run Riggins in this hull but haven't decided yet, one step at a time, we'll see?
_________________ Hasta La Vista Baby |
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