ASPECT RATIO-  Span²/ Planform Area

BEAM TO LENGTH  RATIO- Craft width/ Craft length.

DENSITY -AIR TO WATER- Air x 12.5 ˜ water.
So if you are going 10 knots in the water it is approximately equal to 125 knots in the air.

DRAG=½p U²S CD
      Where  p is the density of the fluid
              U is the speed of the foil
              S is its plan area
                  CD is the drag coefficient


HPCFLE %- Distance of highest point of camber from the leading edge/Chord length

LBS FLOATATION = (volume) Liters X 2.25984.   2% less for fresh water.

LIFT=½p U²S CL
Where  p is the density of the fluid
            U is the speed of the foil
            S is its plan area
            CL is the lift coefficient



'REYNOLDS NUMBER'- Re = p l U/u
Where U is the fluid or craft speed and l is a typical length (e.g. chord in the case of a foil).
If l is in ft. and U ft./sec. The value of p / u for water at 15°C is 7.7x104 and for air 6.3x103.

SURFACE ROUGHNESS-

THICKNESS TO CHORD RATIO-
Section thickness/ Chord length