Design Experts, Rough Water Question.
07-30-2008, 05:02 PM
#31
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Erik:
Compression is a function of tunnel angle fore and aft....not width. Increased width gives increased overall lift.
"Too wide" is a condition that will vary from hull to hull and for a specific application. To me, too wide, is when the width compromises the hull strength and makes the boat overly slippery in turns...... The new Skaters have neither problem it seems.
By the way, my 1968 20' Wing Switzer has a wider tunnel than my 28' Skater....and that is probably where the "new" wide tunnel concept came from.
Vee's in tunnels do a couple of things:
1. provide a natural "wedge" aft to reduce loping
2. In our cats the vee went full length in the tunnels to aid in softening the blow from wave impact in the roughest conditions.
T2x
Compression is a function of tunnel angle fore and aft....not width. Increased width gives increased overall lift.
"Too wide" is a condition that will vary from hull to hull and for a specific application. To me, too wide, is when the width compromises the hull strength and makes the boat overly slippery in turns...... The new Skaters have neither problem it seems.
By the way, my 1968 20' Wing Switzer has a wider tunnel than my 28' Skater....and that is probably where the "new" wide tunnel concept came from.
Vee's in tunnels do a couple of things:
1. provide a natural "wedge" aft to reduce loping
2. In our cats the vee went full length in the tunnels to aid in softening the blow from wave impact in the roughest conditions.
T2x
Thank you!!
By the way, when you speak of great designers you never seem to mention Randy S. of MTI, why is this.....
07-30-2008, 05:20 PM
#32
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Hope you're doing well and planning to shake things up soon. 
Last edited by Miller; 07-30-2008 at 05:38 PM.
07-30-2008, 06:13 PM
#33
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http://www.amalficoastcharter.com/no...barche/?p=1017
Here is a great link I found on Sonny Levis designs.Lot of other stuff in there also --Hickman sea sled etc.Check out the big motor yacht Cat that Levi has on this site.
There is a english translator in the upper right corner.
Here is a great link I found on Sonny Levis designs.Lot of other stuff in there also --Hickman sea sled etc.Check out the big motor yacht Cat that Levi has on this site.
There is a english translator in the upper right corner.
Last edited by tommymonza; 07-30-2008 at 06:16 PM.
07-31-2008, 06:51 AM
#34
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Originally Posted by tommymonza
Why do you think the European Deep V boats of the early years tended to have a short straight keel area with a shallow long forefoot as opposed to the longer keeled deeper forefoot of the American designs.
Why do you think the European Deep V boats of the early years tended to have a short straight keel area with a shallow long forefoot as opposed to the longer keeled deeper forefoot of the American designs.
Originally Posted by 40FlatDeck
By the way, when you speak of great designers you never seem to mention Randy S. of MTI, why is this.....
By the way, when you speak of great designers you never seem to mention Randy S. of MTI, why is this.....
Last edited by mccaffertee; 07-31-2008 at 06:54 AM.
07-31-2008, 07:11 AM
#35
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To Tommy M. Dick Cole invited me to his design studio to draw the Donzi 7 meter. I knew what I wanted, but was not trained in marine architecture. Dick taught me. My name is on the drawing, and it is the shape that I wanted, but Dick is the brains behind it. As far as the psychology, at the time we were on top of the sport boat (read: useless) world, and I wanted something more utilitarian. The model had mild success. When I started Nova, to build v-drive boats, I stretched the design (again with Dick's help) and made a dandy twin inboard. I always hated aluminum stern drives. Still do................
07-31-2008, 07:23 AM
#36
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To T2rex: Speed is a square root function of scale. 16' to 32' is a 2:1 scale. The square root of 2 is 1.41, thus the speed increase is 130mph x 1.41 = 187. The 48' is a scale of 3. Square root is 1.73. 130 x 1.73 = 224mph. Pretty believable stuff when you compare it to the state of th art. 32' Skater, 50' Mystic, all day speeds. Not surprising. I STILL want a 40' Switzer............
07-31-2008, 09:16 AM
#37
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To T2rex: Speed is a square root function of scale. 16' to 32' is a 2:1 scale. The square root of 2 is 1.41, thus the speed increase is 130mph x 1.41 = 187. The 48' is a scale of 3. Square root is 1.73. 130 x 1.73 = 224mph. Pretty believable stuff when you compare it to the state of th art. 32' Skater, 50' Mystic, all day speeds. Not surprising. I STILL want a 40' Switzer............
However, I will acknowledge that my scale may have been exagerated under the "poetic license" laws of OSO.
One other point using your formula.
If Champ boats race at 130 or so on a 1 mile course, then the precise equivalent would be 32 foot offshore cats racing at 187 on a 1.41 mile course, and 48' cats racing at 224 on a 1.73 mile course.
Like I said, nothing really compares to the cojones of a Champ boat driver.
T2x
07-31-2008, 09:20 AM
#38
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Nuff said
T2x
07-31-2008, 09:40 AM
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Basically my original question - but you said it better!
Great designer??? And this may be out of line, but I was under the impression that he was very close to Skater, made some cash in the middle east, came back and started MTI as a direct result of Skater's hard work and years of efforts? Please correct me if I am wrong and I will remove this statement.
Great designer??? And this may be out of line, but I was under the impression that he was very close to Skater, made some cash in the middle east, came back and started MTI as a direct result of Skater's hard work and years of efforts? Please correct me if I am wrong and I will remove this statement.
07-31-2008, 10:18 AM
#40
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I allways heared and thought that a "longer" running surface will give you more lift. thus., more speed. but more friction. less speed. With the steps and cats.. do we have both ?
What about rough water handing and deadrise? Deeper "V"s better in the rough but slower? Wider "cats' stable but now your driving a Cestna.. It's an age old debate... but I wonder is there will be a design that uses a combination of ALL the evolutions and cats and "V" hulls? A hybrid?
I was involved with the testing of the Black Hawks and step in Lake "X" back in eraly 90's.
I am a "step" advicate even tho my current boat don't have one. (my Dad had a 12'l ittle speed boat in the late 60's with a step)
And the big question.. What can I possibly do to a "V" hull. (Avanti = Coyote Beep Beep hull by Arronow.
)
To gain speed and "landing" flatter in lieu of often "stern" landing. Great rough water boat but I thnk it's a bit stearn heavy ..
T2.. I respact your inputs and expertise.
Thanks for your comments.
What about rough water handing and deadrise? Deeper "V"s better in the rough but slower? Wider "cats' stable but now your driving a Cestna.. It's an age old debate... but I wonder is there will be a design that uses a combination of ALL the evolutions and cats and "V" hulls? A hybrid?
I was involved with the testing of the Black Hawks and step in Lake "X" back in eraly 90's.
I am a "step" advicate even tho my current boat don't have one. (my Dad had a 12'l ittle speed boat in the late 60's with a step)
And the big question.. What can I possibly do to a "V" hull. (Avanti = Coyote Beep Beep hull by Arronow.
)To gain speed and "landing" flatter in lieu of often "stern" landing. Great rough water boat but I thnk it's a bit stearn heavy ..
T2.. I respact your inputs and expertise.
Thanks for your comments.
