obvert
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ORIGINAL: AW1Steve
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ORIGINAL: geofflambert
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ORIGINAL: Symon
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ORIGINAL: pws1225
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ORIGINAL: Symon
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ORIGINAL: pws1225
And just what the frig is a Froude limit? I'd check Wikipedia but that source seems discredited now. 
It's the area just past the second gator outside the city limits of Tate's Hell  J
Well frig me! I shoulda knowed that. 
It’s kinda funny because I’m visiting my sister, who’s a designer at GD Electric Boat in Groton. I asked her the question .. “so .. just what the frik is a Froude limit?” You would not believe the “look” I got. Anyway, this is our collective take.
Froude number is ‘jargon’ that’s used as a way of talking about hull speed and wave resistance (drag). The energy to propel a hull through water is transferred to the water, creating standing waves (bow and stern waves). As speed varies, these waves change shape, magnitude and angle (wavelength, phase speed, etc. for the tech heads); they constructively and destructively interfere with one another. Points of interference have a pronounced effect on drag. Drag is relatively proportionally linear to power (speed) up to a first interaction point where it increases dramatically because of a shift in the wave train characteristic.
A simplistic way of looking at it, but one suitable for game terms, is this is the ‘economic’ cruise speed point. A second interaction point is where the ship kinda, sorta, ‘outruns’ the bow wave, thereby effectively constructively converging it with the stern wave, causing a huge shift in the wave train characteristic. Simplistically, this is the vessel’s effective hull speed, because power to make another half knot would be prohibitive (if it even exists) against the added drag.
The Froude number is the characteristic hydrodynamic flow velocity divided by the square root of a characteristic length. Because all vessels have different lengths, hull forms, etc., the Froude number permits comparison between heterogeneous vessels, because standing wave pattern generation is similar at similar Froude numbers for dissimilar vessels.
The Froude limits are (very simplistically) those points where the wavelength of the characteristic standing wave pattern is approximately ½ and 1 of the characteristic length of the vessel (tech heads can think of pi and 2pi superposition). It wouldn’t be too far off to think of Froude numbers (limits) as the hydrodynamic equivalent of Mach numbers.
Hope this helps. JWE
JWE, this is probably not your best post, but I'm thinking it's the best I've seen, at least for a while. Thank you for this instructive post. Let me digress. It's likely not the best I've seen from you, in part because I've noticed you craft excellent posts frequently. You also know a lot of stuff most of the rest of us don't know. I don't know what the WITPAE gamers would do without your input. You are a more important asset to this forum than me, without question. That's all.
+1.
+1
This stuff is amazing. Thanks for taking the time JWE
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"Success is the ability to go from one failure to another with no loss of enthusiasm." - Winston Churchill
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RE: SOT: Naval Architects of Lore May Have Been Right A... - 
Ciao. JWE
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