How does SACS compute the default drag coefficients for wind load computation?

Hi all,

With reference to section 3.3.1 of the Seastate manual in SACS, I would like to inquire how SACS computes the default drag coefficients for tubular and non-tubular members (example for I beams, plates, etc.)? Is it based on empirical values or a formula?

Furthermore, the Seastate manual states a drag coefficient of 1.5 for non-tubular members and 0.5 for tubular members (see screenshot below), may I ask if these are 'rule-of-thumb' values or based on some design code?

Finally, how is the wind load being computed with these parameters (wind velocity, drag coefficient, etc.) - what is the formula being used?

Thank you for taking the time to consider my query! Slight smile