Displacement (or Sectional Area) Sheet (English
Units)
Description:
This spreadsheet
computes hydrostatic volume characteristics relating to
station cross sectional areas. Basically it sums up the area under a
sectional area curve to obtain the displaced volume and it takes moments
to obtain the longitudinal and vertical centers of buoyancy for an input
waterline.
If the input waterline is level, the data obtained may be used as an
input source for a vessel's "Curves of Form." Inputs are
based on a Lines Drawing with ten stations starting at zero and ending at
Station Ten. This Lines Drawing has customary half stations at each
end to compensate for vessel fineness. The numerical integrations
contained in these calculations are based on Simpson's Rules.
Though optional, this spreadsheet is best utilized in
conjunction with a Waterplane
Sheet (Product WP-e)
and Waterline Input/Output Sheet (Product
WL-IO-e).
A further enhancement is dynamically combining this sheet along with a Waterplane
Sheet and a Waterline Input/Output Sheet. The product that combines
all these sheets together is called a Waterline Hydrostatics Data Sheet
(Product WL-hydro-e). This
later enhanced combination facilitates faster and easier
computation for a given waterline. In the combined case, calculations
are more automated, significantly minimizing the data entry input time.
Electronic
Document Type: Microsoft® Excel®
spreadsheet Cost:
$7.50 US funds
Number of
Pages: Includes an template (or input)
sheet, along with an example sheet, an instructions
sheet and a use terms sheet.
Inputs:
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The following dimensional and property input data are required:
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Clearly document the WL condition being evaluated.
Enter the forward draft (TFWD), midships draft
(TMID), aft draft (TAFT) and
maximum draft (T). |
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Then enter
the
station spacing (s).
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Enter in half the hull's
cross sectional area (SA) for each station.
Note the vessel must be divided into ten
stations (this yields eleven cross sectional areas) with a half
station at each end (this adds two more cross sectional areas).
This means a total of thirteen input cross sectional areas are
required. Bonjean Curves may be used to quickly determine
the cross sectional areas. They also may be determined by
calculation, a CAD program or some other means. |
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For each cross sectional area the vertical
distance from the Baseline to the centroid of each cross
sectional area is required. For the template this value
is called a vca and thirteen of these values are required.
These values may determined using a Lines Drawing, through a CAD
program or through some other acceptable means. |
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For vessel's with overhang; add in the aft
overhang volume as well as the longitudinal (from
Station 5) and vertical centers (from Baseline) of
buoyancy for this volume. This data is often needed
because many vessels that end their LBP (in the Lines Drawing) at
the center of the rudder post. This correction compensates
for the volume that is displaced aft of the rudder post, which may
be substantial. |
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Finally enter
the specific gravity (S) of the water that the vessel is
in. If this is in regard to a stability test enter the average
specific gravity taken at the time of stability test. |
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Optional Input Items:
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Vessel name, project description, client and
calculation date and time. |
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Outputs:
| The
automatic output generated by this spreadsheet are the
displaced volume (V),
displaced weight (W),
longitudinal center of buoyancy (LCB),
and vertical center of buoyancy(VCB).
Note the LCB obtained is the distance from Station 5. |
Suggested
Reading (see
References page for
more detail on these items):
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Microsoft Excel user manuals |
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Principles of Naval Architecture, Edward V. Lewis, SNAME |
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Basic Ship Theory, Rawson & Tupper |
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Applied Naval Architecture, Robert B. Zubaly |
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Introduction to Naval Architecture, E. C. Tupper |
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Introduction to Naval Architecture, Thomas Gillmer and
Bruce Johnson |
Terms:
Prior to purchase, read our
End
User License Terms.
Download
Now:
Click one of the following buttons to pay.
After payment you will be taken directly to the download page.
Minimum
System Requirements: Windows 95/98/NT/2000/XP
Sample:
A sample document is shown below.
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