Deadrise as measured at the transom is a very important factor in how a hull
will handle the water - more deadrise equals less efficient planing but
better rough water handling - but there are other factors, such as fineness
of entry at the bow, how quickly the deadrise changes as it goes astern,
whether there are "pads," "lifting strakes," and "spray rails" built into
the hull or not, and on really high performance hulls, things like "steps."

Also, I would add, I have a 1978 Trojan 26, so much like the Chris Craft you
mention, and it handles rough water like a dream. I don't know the deadrise
number, but it isn't much. Why is it so good? I'm not sure, but I think it's
because it's a semi-planing hull, not full-planing, at least as powered by
its probably original 225 hp Chrylser 318, and so it never ends up planing
on just the aft fraction of the hull. In other words, you don't have to
worry about slamming down onto the water from waves if most of the hull
never leaves the water.

Last year in short 6 footers, I had it slowed down probably to about 12
knots, but not for slamming - it was just too rough to hold on, otherwise.
The boat itself handled it all with great poise - although admittedly not at
very high speed - although observers on land later told me we were throwing
a great deal of spray!

There are lots of design complexities, and the deadrise number, although
important, isn't the entire story.

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Charles T. Low
- remove "UN"
www.boatdocking.com/BDPhoto.html - Photo Contest
www.boatdocking.com
www.ctlow.ca/Trojan26 - my boat

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"C. J. Klingman" wrote in message
...
Deadrise is measured at the transom.

Your numbers are logical to me. Larger boats would be more likely to be
offshore boats, needing more 'V' for comfort in the normal choppy seas.
Deckboats are heavy damn things for their length and need all the help
they
can get to plane, and would almost never be used offshore. Lots of older
boats, Crist Craft runabouts, etc. have almost no deadrise, better to
plane
with the lower power of the time, comfort be damned.