[PSUBS-MAILIST] Re: Positive bouyancy

[Michael B Holt <tlohm@juno.com>]

On Mon, 3 Mar 2003 16:21:02 -0500 "Alec Smyth" writes:
>

>In general, the force on a hydroplane can approximately be calculated 
>from the following equation:
>
>F =3D C A sin(a) 0.5 r v2	 F : Force on hydroplane (kg)=20
>C : Friction coefficient (C =3D 0.1)=20
>A : Area of hydroplane (m2)=20
>v : Velocity of boat (m/s)=20
>r : density of water ( r =3D 1000 kg/m3)=20
>a : angle of hydroplane (deg)=09


This is similar to the formula for rudder effect.   It's called
Joessel's formula.

P = KAU^2 sin (a ) / 0.195+0.035 sin (a)

P = pressure in pounds
K = 0.787 (when the units are English)
A = area of rudder, sq. ft.
U = speed of the ship in knots
a = rudder angle

Turning moment can also be calculated, from this.

M = KLAU^2 sin(a) cos (a) / 2[(0.195+0.305 sin(a)]

M = turning moment (ft. lbs.)
L = length of the ship (ft.)
 



Mike H.


________________________________________________________________
Sign Up for Juno Platinum Internet Access Today
Only $9.95 per month!
Visit www.juno.com