It's the distance that the outer edges of the bottom hull panels sit above the keel. This decides the relative roundness or flatness of the bottom of the boat, and is very important to stability. When I built my Cormorant, my deck was a little too narrow (pinched) in the midship area. I squeezed the hull to meet the deck, and changed the deadrise from 1.5" to about 2.25". That was all it took to make the boat very unstable in any chop. Oh well, live and learn ;-)

Mark

: I can't find a definition anywhere. What is it ??
: In regards to the Cormmarant 16

: Thanks Terry