Careful on those calcs ...flat bottom boats will generally have a higher
righting moment than V-bottom boats. If you are making an assumption about
the waterline being fixed at a particular location on the side of the boat,
then 'moving' the bottom deeper into the water to create the V-hull also
greatly increases the boat's displacement. The displacement is a constant,
or close to it. Since a righting moment is the righting arm times the
boat's displacement, you might find that looking at the righting ARM graphed
against the degrees of heel would be more useful to you ...and industry
standard. I don't know anything about the Hulls program, but if it lets
you, you should use the free-floating (trim and heel) setting so that the
s/w tells you what the hydrostatics and waterline turn out to be.

Brian D



"Lumberjack" wrote in message
news
Okay, I know that this is a stupid newbie question, but I'm planning to
build a partially decked 15' rower / daysailer similar to Devlin's Egret.
I've downloaded the HULL chine design program and played with traditional
dory designs.

I find that if I use a v bottom at 20 degrees heel, the resulting righting
moment goes up 50 percent compared to a traditional flat bottom dory.

1. a v-bottomed dory is really a skiff, right?
2. aside from losing the ability to easily beach the boat, are there any
downsides to building with a v bottom? My goal is to increase ultimate
stability, and I think I can live with a little additional initial
tenderness
3. the primary job of this boat is as a rowboat. Will a v bottom hurt in
this regard?

I have the .hul file, if that would be helpful in providing advice.