"Red" wrote in message
...
There was a thread back a ways that was about roll rate and comfort Vs.
safety. Just thought if anyone was interested there are two lists on the
boatdesign.net/forums that show Ted Brewer's " motion comfort ratio" of
quite a few different sailboats. May be useful as a comparison chart for
anyone looking at buying a boat. First list is of boats with a
comparatively high MC ratio, and the second list is of boats with lower
ratios.

http://www.boatdesign.net/forums/showthread.php?t=20655
Scroll down to find the lists in two posts.

Red

There is a degree of subjectivity in that. The two largest factors affecting
comfort are the condition of the person's inner ear and their body
morphology. The inner ear obviously is the source of balance but body
morphology is interesting. These boat studies tend to be old and don't
account for obesity and the roll pitch comfort of the human body itself as a
result of mechanical displacements of large amounts of fat tissue. A thin
person may be quite comfortable in those old fashioned vibrating belt
machines but an obese one would experience extreme discomfort as they fly
about all over the place. An obese person's fat tissues can couple into the
motion of the boat in a positive sympathetic mode, increasing the motion of
the boat and also of the person itself. This mechanical regime would
increase until non linearities in the adipose tissue or transient boat
displacements introduced harmonics and dampened the overall response. The
concepts of comfort with regard to boat motion are indeed true, but the
specifics, namely rates and axis should be reconsidered due to the ever
increasing size and elasticity of boat passengers. This is exceedingly true
in the States, where eating has become full time sport.

Nigel