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[PSUBS-MAILIST] Re: Working on a spreadsheet again



Charles Samardza wrote:
> 
> Hi,  there is a formula for what you want, I got it out of a 'Handbook
> of Ocean Engineering' that I found in the library.
> The formula is   "shaft horsepower) equals "displacement in tons to the
> 2/3 power" times "speed in knots cubed" times "0.005" times "efficiency
> factor"

It's in Busby, page 397.

> Displacement can be approximated with "(height x width x length) / 60"
> The efficiency factor is a combination of hydrodynamic efficiency,
> propeller efficiency, and efficiency of power transfer.

But there's no explanation of any of it.  Thanks.

> Technically the efficiencies will vary depending on speed, however for
> general comparison at max speed, it give a number for comparison.  The
> lower the number the better, both the Nautilus and the ww2 German type
> 21 submarines have an efficiency of about 1.

How does one calculate the efficiency?
  


Mike