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  #1  
Old 04-06-2008, 10:05 AM
SSEleanor SSEleanor is offline
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Cathedral Hulls??

Has anyone ever owened one, or been on one, how do they preform? how do they handle, weather, turns etc? horespower to weight speed etc? how do they pair up with surface drives? aerodynamics? hydro dynamics?
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Old 04-06-2008, 03:06 PM
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What are they? Never heard of them
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Old 04-06-2008, 06:47 PM
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Cathedral Hulls

A modification of the "V"-bottom hull concept are tri-hulls or cathedral hulls. The tri-hull boat is the traditional "V" hull with additional outside hulls. This design offers somewhat more stability than the traditional "V"-bottom at rest, but it gives a rougher ride in heavier waters due to an increased surface area fore.

The tri-hull design features a central deep vee section with smaller side sponsons. Under way the central section of the hull makes initial contact with oncoming waves while the side sponsons are riding high and dry to a point about half way back along the hull. Once the hull is at rest the deeply vee'd side sections of the hull then come into full water contact to provide additional stability.

Dick Cole has been credited with the first commercial "Cathedral" tri-hull (Thunderbird boats) in 1958. Cole designed boats in South Africa, Canada, US. He once raced a Hickman Sea Sled, a twin hull configuration which was the stimulus when originating the Cathedral Hull. The hull design was also called "Gull Wing" by OMC.

The true "tunnel hull" or "catamaran" is quite different from the tri-hull or cathedral hulls, even though the "modified" version of tunnel hulls features a centerpod hull - thus three hulls. Aerodynamic forces generate a more important portion of Lift/Drag with tunnel hulls.
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Old 04-06-2008, 09:32 PM
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There is a notable difference between a cathedral and a tri hull.

The cathedral hull is usually heavier then a more conventional shape, turns at slower rate, slower to climb up on plane, usually consume more fuel then a more conventional hull, isn't as well suited for rough water work, though it does take to slight and moderate chop well.

Their advantages are a full deck line, which is why the currently popular "deck boats" use this hull form. High initial stability and high speed stability are also hallmarks of this shape.

They tend to be dry running boats, because of the square deck line. They also are pretty comfortable in a moderate chop.

Like all choices in yacht design this shape is an example of the compromise necessary to get an end product.
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Old 04-07-2008, 01:30 PM
SSEleanor SSEleanor is offline
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Cathedral hull / Vee hull / tunnel hull all combined?

I'm working on a design of the above, it starts at the bow like a traditional Vee shaped hull then the vee subsides up into the hull where the deck curls down to reach below the wate line, creating 2 tunnels. Im all most finished the 3D model which I hope to show on the Boat design gallery for yer opinion. In the mean time, can you imagine whats going on and know if there is anything out there simular?
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Old 04-07-2008, 02:43 PM
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SSEleanor - Sounds like you are working on a new concept. Look forward to your pictures.

As PAR says, all designs turn out to be a compromise, like any engineering!
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Old 04-08-2008, 02:54 AM
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Austal Fast ferry

Quote:
Originally Posted by SSEleanor View Post
I'm working on a design of the above, it starts at the bow like a traditional Vee shaped hull then the vee subsides up into the hull where the deck curls down to reach below the wate line, creating 2 tunnels. Im all most finished the 3D model which I hope to show on the Boat design gallery for yer opinion. In the mean time, can you imagine whats going on and know if there is anything out there similar?
I underlined similar because this Austal ship at 127m is much bigger, see the size of the car in the foreground .
However these vessel performed exceptionally well, I often watched them doing sea trials at 40+Kn.

This from their site: "With the handover completed on April 13, the new 127 metre, Auto Express 127 trimaran built by the West Australian shipyard, Austal, for Fred. Olsen, S.A. is quite simply the most significant vessel to arrive on the fast ferry stage and is set to allow fast sea transportation to improve and open up new markets beyond the ability of existing fast ferry design for both commercial and military operators." and ""The characteristics of this new vessel, with a length of 126.7 metres and beam of 30.4 metres, will improve overall efficiency in terms of passenger capacity, deadweight and freight lane metres by more than 35%. At the same time passenger comfort will increase by 25% to 40% depending on the routes we operate".
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Cathedral Hulls??-benchijigua_2.jpg  Cathedral Hulls??-benchijigua_3.jpg  Cathedral Hulls??-benchijigua_1.jpg  

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