Hydrostatic Weighting

Hydrostatic weighting, abbreviated as \(\rho_b\), also called underwater weight, is how you can determine the average density of any object without nead for volume or measuring the mass per unit volume.

 

Hydrostatic weighting formula
\(\large{ \rho_b = \rho_w  \;  \frac { W_b } { W_b \;-\; W_{im} } }\)
Symbol	English	Metric
\(\large{ \rho_b }\)  (Greek symbol rho) = density of body	\(\large{\frac{lbm}{ft^3}}\)	\(\large{\frac{kg}{m^3}}\)
\(\large{ \rho_w }\)  (Greek symbol rho) = density of water	\(\large{\frac{lbm}{ft^3}}\)	\(\large{\frac{kg}{m^3}}\)
\(\large{ W_b }\) = weight of body	\(\large{lbf}\)	\(\large{N}\)
\(\large{ W_{im} }\) = weight of immersed body	\(\large{lbf}\)	\(\large{N}\)