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  #16  
Old 04-20-2017, 02:39 AM
bhnautika bhnautika is offline
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Q1 all three
Q2 Yes I am making some assumptions but light displacement boats tend to have flattish bottoms coupled with the flared sides would generally mean the CB would move out significantly making them stiff but you can get considerable rolling accelerations.
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  #17  
Old 04-20-2017, 01:16 PM
mcm mcm is offline
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Quote:
Originally Posted by bhnautica
light displacement boats tend to have flattish bottoms coupled with the flared sides would generally mean the CB would move out significantly making them stiff
@25deg angle of heel the designer calculated that the transverse shift of the center of buoyancy will only be 0.79'(0.24m). Hull bottom is 2'(0.61m) bellow the waterline creating a 21deg. dead rise angle to the waterline.

Still, my main concern is whether that much (flare) in the top-side will kill the boats momentum as it heaves in a seaway.


Quote:
Originally Posted by Mr Efficiency View Post
name the boat supply some pix/lines
The designer is still making adjustments to the lines of the boat which is not yet named, and I don't have permission to reproduce the designer's work. As a consumer I am looking for second opinions before I spend too much money.
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  #18  
Old 04-20-2017, 06:56 PM
bhnautika bhnautika is offline
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It seems my assumptions about the mid section shape are wrong as more information comes to hand (21 degree dead rise). So is this close to the shape.
I may be slow coming back.
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Is this too much flam??-section.jpg  
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  #19  
Old 04-20-2017, 07:46 PM
Mr Efficiency Mr Efficiency is offline
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Quote:
Originally Posted by mcm View Post
The designer is still making adjustments to the lines of the boat which is not yet named, and I don't have permission to reproduce the designer's work. As a consumer I am looking for second opinions before I spend too much money.
So it is a new design with no examples in use ? Is there some reason to fixate on this boat in preference to existing, proven designs ?
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  #20  
Old 04-20-2017, 09:08 PM
mcm mcm is offline
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Quote:
Originally Posted by bhnautika View Post
So is this close to the shape.
Thank's bhnautika, that's close, but I made a mistake.
The dead rise angle from the bottom of the center-line to the waterline is 31deg. not 21deg.
21Deg. is the dead rise angle from the bottom to 1' (0.3048m) bellow the waterline.
And at 1' (0.3048m) below the waterline the the mid-ship beam is 5.13' (1.56m) overall or 2.57' (0.78m) from the center-line, while your mid-ship beam at 1' (0.3048m) below the waterline looks to be 4.55' (1.39m) overall, or 2.28' (0.69m) from the center-line.

Quote:
Originally Posted by Mr Efficiency
So it is a new design with no examples in use ? Is there some reason to fixate on this boat in preference to existing, proven designs ?
Yes, it's a new design, and my fixation is to be more involved in the process.
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  #21  
Old 04-22-2017, 05:04 AM
Mr Efficiency Mr Efficiency is offline
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Originally Posted by mcm View Post
Yes, it's a new design, and my fixation is to be more involved in the process.
Maybe best to wait and see, rather than be the guinea pig.
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  #22  
Old Today, 12:42 AM
bhnautika bhnautika is offline
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Mcm how about this shape. Heave can be influenced by more than just mid section shape , L/B ratio, L/disp, radius of gyration and wave spectrum. Then there is heave and stabilty. Top side flair may add resistance to heeled waterlines if they are to asymmetric, if you have concerns talk it over with the designer.
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Is this too much flam??-section2.jpg  
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  #23  
Old Today, 03:12 AM
nzboy nzboy is offline
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My take on this design is its very similar to racing designs of late 70s and 80s
before canting keels and all the volvo stuff. You actually need a wide shear beam .As the boat heels the waterline beam increases and increases stability but draught decreases hence less resistance in theory
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