This is a illustration of application for Froude Number in ship, Froude Number is important for designer of ship. In Naval Architecture this is as reference to know and choice their design. Fn or Froude Number can image from speed, gravity, and length. The color of blue is meant as ideal between speed and resistance, Cw is coefficient of water line, Cw is gated from wide of water line with wide from B and L, Cw usually in draft. Why this is ideal? Because in Fn that blue color usually length and speed make coefficient water line is small, so the resistance of ship small too, as we know the resistance in ship have friction, wave, eddy making, and air resistance.
- Friction is impact from move of ship, move ship make flow, and this flow collision whit the flow in water, whit different word friction isn’t from surface with flow water
- Wave is certain in sea, and the shape can image with wave of sound
- Eddy making this is in surface of plat ship, make wave that this is like tornado but very small and this tornado pull the ship to back
- Air is collision with super structure of ship ( the building in above water)
But in fact, the friction resistance is very big value compare with anythink. The ideal is 0 – 0.18 , 0.2 – 0.23 , 0.3 – 0.35 , > 0.5 and more big Fn have more big speed. And the gray is inverse from blue.