"Waterplane" and "underwater profile"

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cfwahl
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"Waterplane" and "underwater profile"

Post by cfwahl » 30 Oct 2005, 02:49

Ref: Class Rules D.2.2

Is "waterplane" the section through waterline, or something else?

Is "underwater profile" restricted to that (wet) portion of the hull beneath water when at rest in calm, or to any surface that might become "underwater" -- such as, the deck when the boat dives in a blow?

Is the "underwater profile" any particular one (such as transverse sections perpendicular to the centreplane), or any (sectional is assumed) profile at all?

What's the distinction between "underwater profile" and "undersurface" (which is illustrated at the end of the Rules)? Does the latter include aspects of the former?
Charles Wahl

Lester
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Re: "Waterplane" and "underwater profile"

Post by Lester » 30 Oct 2005, 07:22

cfwahl wrote:Is "waterplane" the section through waterline
Hi Charles

Yes, the way I read it. By "section" I assume you mean "slice" or plane.
Is "underwater profile" restricted to that (wet) portion of the hull beneath water when at rest in calm
Yes, the way I read it.
Is the "underwater profile" any particular one (such as transverse sections perpendicular to the centreplane)
The way I read it, it is the projection of the hull onto a vertical, fore and aft plane. A silhouette if you like of the side of the hull, an outline of the hull seen from the side.
What's the distinction between "underwater profile" and "undersurface"
The profile is a single line, while the undersurface is a surface.
Lester Gilbert
http://www.onemetre.net/

cfwahl
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Joined: 23 Nov 2003, 23:01
Location: CAN 62

Re: "Waterplane" and "underwater profile"

Post by cfwahl » 30 Oct 2005, 18:28

Hullo, Lester,
Lester wrote:By "section" I assume you mean "slice" or plane.
Quite right.
Lester wrote:
cfwahl wrote:Is the "underwater profile" any particular one (such as transverse sections perpendicular to the centreplane)
The way I read it, it is the projection of the hull onto a vertical, fore and aft plane. A silhouette if you like of the side of the hull, an outline of the hull seen from the side.
So that's only a single profile, what's sometimes called the "rocker"? On first reading, I thought that the intention of the rule was to prohibit hollows in any conceivable profile, a section taken on any plane. But the separate paragraph on subsurface, specifying transverse and measured parallel to waterplane, seems to limit consideration of things; so that's why I'm wondering about the extent on limitations WRT underwater profile.

Thanks for the input,
Charles Wahl

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