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Old 04-05-2019, 15:05   #136
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Re: Calculator_pi New Finished Plugin for OpenCPN

S P M 1984 Volume 1-1.pdf
Page 3-55 (Equations 3-40 and 3-39) and 3-66 (Example)

Have the equation needed for wind and fetch conditions to solve wave height.


Woods Hole calculator uses this formula


https://woodshole.er.usgs.gov/projec...h_limited.html




Also in Guide to Wave Analysis and Forecasting page 85 and 86 Wave Growth in shallow waters.
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Old 28-12-2022, 08:19   #137
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Re: Calculator_pi New Finished Plugin for OpenCPN

calculator_pi has been updated for OpenCPN 5.7.1-beta/5.8.

Now in the master catalog.

Please test and post comments here.

Still needs work. Basic functions seem ok.

Mike
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Old 25-09-2024, 07:12   #138
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Re: Calculator_pi New Finished Plugin for OpenCPN

Bonjour,
Je ne plus mettre à jour le plugin calculator
"Download error: The requested URL returned error: 404"
Que faut-il faire?
Bien cordialement
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Old 25-09-2024, 07:25   #139
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Re: Calculator_pi New Finished Plugin for OpenCPN

bernard ...

Which OS please. And which version OpenCPN?

Mike
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Old 25-09-2024, 07:33   #140
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Re: Calculator_pi New Finished Plugin for OpenCPN

The last Version 5.10.2 and PC Ubuntu 24.04.1 LTs


Bernard
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Old 25-09-2024, 07:52   #141
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Re: Calculator_pi New Finished Plugin for OpenCPN

Bernard ...

I need to make an update. Will let you know when this has been done. Windows was/is ok.

Mike
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Old 26-09-2024, 07:28   #142
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Re: Calculator_pi New Finished Plugin for OpenCPN

I found another very useful formula for Calculating Torque (KgM or Nm) on your rudder. This is very useful for determining the effectiveness of an autopilot driver or for figuring out the blade size for a second wind-vane steering rudder, or servo-pendulum.


To calculate the torque on a rudder, you can use the following formula:
C=S×[(0.4×Lg)−Lc]×V2×K
Where:
  • C is the torque in kgm
  • S is the total surface area of the rudder (height (H) x width (Lg)) in square meters
  • H is the height of the rudder in meters
  • Lg is the width of the rudder in meters
  • Lc is the compensation width in meters
  • V is the maximum speed of the boat in knots
  • K is a coefficient based on the total rudder angle (e.g., 70°: K = 15.89, 80°: K = 17.80, 90°: K = 19.52)
Additionally, you may need to apply correction factors based on the type of boat:
If you have any specific details about your boat or rudder, feel free to share, and I can help you further refine the calculation!


https://www.peachment.co.uk/torque-calculation/


Also this can be used JavaFoil (mh-aerotools.de)


I also have a spreadsheet for this calc.
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Old 26-09-2024, 07:57   #143
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Re: Calculator_pi New Finished Plugin for OpenCPN

Bernard ...

Please update the catalog. Could you try another install? A version for your OS should now be available.

Mike
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Old 26-09-2024, 13:00   #144
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Re: Calculator_pi New Finished Plugin for OpenCPN

Bonsoir,
Merci Mike ça fonctionne.


Cordialement


Bernard
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Old 27-09-2024, 06:38   #145
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Re: Calculator_pi New Finished Plugin for OpenCPN

Brewer’s comfort ratio, you need to run the following formula: Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam↑1.33), where displacement is expressed in pounds, and length is expressed in feet.


You can use the following guidelines to interpret comfort ratio results: numbers below 20 indicate a lightweight racing boat; 20 to 30 indicates a coastal cruiser; 30 to 40 indicates a moderate bluewater cruising boat; 50 to 60 indicates a heavy bluewater boat; and over 60 indicates an extremely heavy bluewater boat. If evaluating a larger boat, say 45 feet or longer, expect your results to be skewed a bit higher on this scale; if the boat is quite small, say 25 feet or less, they will be skewed slightly downwards.
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