In reading some specs for a Hunter 22 I ran across a term that I am not familiar with. The term is capsize screen. For this boat it was listed as 2.15. I tried to look up the meaning in several reference works, but to no avail. I would appreciate hearing a definition. thanx in advance, gary guisinger
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H
Henry Scurlock
from right here at HOW
From this site http://www.c-2.com/boats/ratiosall.tpl?wc=23&site=HOW&fno=0 *Capsize screen The Capsize Screening Formula was developed by the U.S. Sailing Association as a rough rule of thumb, helpful in comparing the initial resistance to capsize of various boats. Boats with a Capsize Screen factor of 2 or less will have a normal initial resistance to capsize and will in general be safer offshore boats than boats which exceed this value. The lower the value, the better, all other things being equal.
From this site http://www.c-2.com/boats/ratiosall.tpl?wc=23&site=HOW&fno=0 *Capsize screen The Capsize Screening Formula was developed by the U.S. Sailing Association as a rough rule of thumb, helpful in comparing the initial resistance to capsize of various boats. Boats with a Capsize Screen factor of 2 or less will have a normal initial resistance to capsize and will in general be safer offshore boats than boats which exceed this value. The lower the value, the better, all other things being equal.
G
Gary Guisinger
A
Adrian Iapalucci
Hello
Gary, I just bought a Hunter 22'. How long have you had your's? Are you pleased with it. My email is: iapalucci@bcinet.net.
Gary, I just bought a Hunter 22'. How long have you had your's? Are you pleased with it. My email is: iapalucci@bcinet.net.
C
Chuck
H22
I've had SHANNON, my 1981 H22 for 2 seasons now. She's a great boat. I can keep up sail in weather/winds that on my beloved old Cat22 I had to motor through. I will be adding a storm jib this year to make life a lot easier though. According to my inclinometer, Shannon has gone over to a 45+ degree heel and we have so far never had water over the coaming, never did dare it with my Cat. As a general rule if she heels over 30 degrees she'll try to head into the wind, when it happens twice I switch to a smaller jib and reef the main. I've gotten caught in 40k winds with this boat and while it wasn't for the faint of heart, she took us home quite handily. (thankfully my wife wasn't there). ENJOY
I've had SHANNON, my 1981 H22 for 2 seasons now. She's a great boat. I can keep up sail in weather/winds that on my beloved old Cat22 I had to motor through. I will be adding a storm jib this year to make life a lot easier though. According to my inclinometer, Shannon has gone over to a 45+ degree heel and we have so far never had water over the coaming, never did dare it with my Cat. As a general rule if she heels over 30 degrees she'll try to head into the wind, when it happens twice I switch to a smaller jib and reef the main. I've gotten caught in 40k winds with this boat and while it wasn't for the faint of heart, she took us home quite handily. (thankfully my wife wasn't there). ENJOY
D
Doug King
Capsize Screen Ratio meaningless for small boats
I saw a post which said it represented initial resistance to capsize, which is not quite right. It is a rough measure of the boats tendency to STAY capsized if rolled over. This is a substitute for the "Limit of Positive Stability" which is difficult to calculate and requires lots of measurements not normally given. The Capsize Screening Ratio is a measure of displacement to beam, and says nothing about the boat's stability under normal sailing conditions. The Capsize Screen is meaningless for small boats which will not be encountering large breaking waves. By "large waves" I mean waves that are taller than your boat is long, at which point anybody with a lick of sense has gone in. Fresh Breezes- Doug King
I saw a post which said it represented initial resistance to capsize, which is not quite right. It is a rough measure of the boats tendency to STAY capsized if rolled over. This is a substitute for the "Limit of Positive Stability" which is difficult to calculate and requires lots of measurements not normally given. The Capsize Screening Ratio is a measure of displacement to beam, and says nothing about the boat's stability under normal sailing conditions. The Capsize Screen is meaningless for small boats which will not be encountering large breaking waves. By "large waves" I mean waves that are taller than your boat is long, at which point anybody with a lick of sense has gone in. Fresh Breezes- Doug King
S
Steve Adores
CSR does include resistance to capsize too
Doug, From what I have read, the Capsize Screen Ratio has two major parts. The first is the risk of being unduly easy to capsize, the second being the risk of being stuck in the inverted position for an extended period. This comes from the 1985 Final Report to the Directors - results of the SNAME & USYRA studies into yacht design triggered by the 1979 Fastnet. I agree that it has little to do with small boat sailing, as most any boat with a waterline of less than 30' is at great risk of capsize in breaking ocean waves. Length over this does not guarantee safety from capsize either, but generally speaking, boats over this size criteria can begin to develop values under 2.0., unless they are very wide in beam and/or light in displacement. The beamy-light combination gives a shorter "capsize length" than the actual measured waterline. Small boats inherently cannot produce the stability to score well on the screen formula Maximum Beam / Cube root of Displaced Volume. That is one more reason to pay attention to Small Craft Advisories. Steve
Doug, From what I have read, the Capsize Screen Ratio has two major parts. The first is the risk of being unduly easy to capsize, the second being the risk of being stuck in the inverted position for an extended period. This comes from the 1985 Final Report to the Directors - results of the SNAME & USYRA studies into yacht design triggered by the 1979 Fastnet. I agree that it has little to do with small boat sailing, as most any boat with a waterline of less than 30' is at great risk of capsize in breaking ocean waves. Length over this does not guarantee safety from capsize either, but generally speaking, boats over this size criteria can begin to develop values under 2.0., unless they are very wide in beam and/or light in displacement. The beamy-light combination gives a shorter "capsize length" than the actual measured waterline. Small boats inherently cannot produce the stability to score well on the screen formula Maximum Beam / Cube root of Displaced Volume. That is one more reason to pay attention to Small Craft Advisories. Steve
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