The units used are absolutely essential in the formulas for performance and stability. The constant 1.58 in Derek's stability formula only works for displacement
in pounds (2240 pounds per long ton), other dimensions in feet, and an answer in miles per hour. In the Multihull
Dynamics website, we use the constant 13.8578 to get results in knots of windspeed. If you have specifications in metric units, you must convert them to use the formula with these constants. Or you can convert the formulas to use metric units...the constant will be different.
Hope this helps.