Hey Guys,
Mary is right. Prismatic coefficient will not help any of us sail a boat faster. It is already built into our hull shapes and there is nothing we can do about it.
For those who are interested, it is a ratio of two hull volumes below the waterline. It ranges in value from 0.0 to 1.0. The numerator is the actual hull volume below the design waterline. The denominator is an imiginary hull volume equal to the maximum actual hull cross sectional area integrated over the full length of the boat below the same waterline. So, when this number is small, it means the hull max cross sectional area occurrs for a very short length of the hull with almost straight lines connecting the max cross section of the boat to the bow and stern. You would call it a "pointy" hull shape. On the other hand if the prismatic coefficient is large, like near 1.0, then the hull maximum cross sectional area or near maximum cross sectional area is carried well forward and well aft from the point of max cross sectional area and the hull lines appear full with a blunt bow and stern. A barge hull shape has a large prismatic coefficient. A canoe hull shape has a much lower or smaller prismatic coefficient. See, I told you it wouldn't help you make your boat go any faster.
Bill