# Calculating load for tidal movement

1. Jun 23, 2009

### jamesd442001

Calculating wind load is wind speed squared x .00431 x area in sq. ft. A 5 mph wind with a vertical 100 sq. ft. wing is 10.77 lbs. The mass of salt water is around 854 times greater than the mass of air. Can you use the wind formula and multiply by 854? Does the weight of water at different atmospheres change this?

2. Jun 29, 2009

### stewartcs

What is the context of this question? Various standards would apply and have things such as shape coefficients that will change the resultant force from environmental loadings.

The type of hull (presumably this is for an ocean vessel) may also introduce other factors to consider.

That being said, the final calculation will be some derivative of the basic equation:

F = PA

API 2SK is a good reference for this. For a ship hull the current force on the bow or stern (in lbf) is:

$$F_{cy} = C_{cy}SV_c^2$$

where,

S = wetted surface area of hull including appendages (ft^2)
V_c = current speed (knots)
C_cy = current force coefficient = 0.40 lbf/(ft^2 - knots)

Hope this helps.

CS