I know the most legit way to do this is to go someplace where they have the machinery to do the underwater hydrostatic weighing but is there any other way I can do a rough estimate of how much fat % my body is? I heard there is a skinfold caliber method- something similar to a hip to waist ratio calculator? Also, I am going on a cruise that claims to offer a BCA "class" for $30. Has anyone done this before? What do they do there?