I am not sure if the barometer on my boat is functioning properly, as the needle never seems to move more than 2 or three tenths of an inch. It always says "fair" no matter what the weather is actually doing. It is a Seth Thomas brand. I bought the boat at sea level and moved up to 5000 ft. Is there some adjustment that I need to make on the instrument, or is the range of this Barometer wrong for inland sailing? It goes from 28 to 31 inches.
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Not really
Baro pressure is the total weight of the air above the instrument. Since you are about 1/4 of the way to space atmosphere wise your readings are going to be only 3/4 of what every body else's at sea level are. You would have to change the mechanism to get it to read correctly. I personally have never heard of a baro that was designed to operate at anything other than sea level but there may be some way to adjust yours. Take off the back cover and look for markings along the bar that connects the bellows to the needle.
Baro pressure is the total weight of the air above the instrument. Since you are about 1/4 of the way to space atmosphere wise your readings are going to be only 3/4 of what every body else's at sea level are. You would have to change the mechanism to get it to read correctly. I personally have never heard of a baro that was designed to operate at anything other than sea level but there may be some way to adjust yours. Take off the back cover and look for markings along the bar that connects the bellows to the needle.
Your air pressure is much less than sea level
The air pressure at 5000 feet is 5 inches of mercury less than at sea level. Your barometer must be adjusted or it will be nothing more than a non-functional decoration. The site below shows you the necessary data.
The air pressure at 5000 feet is 5 inches of mercury less than at sea level. Your barometer must be adjusted or it will be nothing more than a non-functional decoration. The site below shows you the necessary data.
On mine there is a small adjusting screw
accessable through a hole in the back. If you tap the local tv weather station they will report the barometric pressure corrected to sea level. 3 tenths of an inch is close to normal change if there are no major storms. The web site "weather underground" is also a good source for these details.
accessable through a hole in the back. If you tap the local tv weather station they will report the barometric pressure corrected to sea level. 3 tenths of an inch is close to normal change if there are no major storms. The web site "weather underground" is also a good source for these details.
Great link, David
I have been wondering where to get accurate readings to calibrate my barometer. This gives all the weather info updated every few seconds at many local stations. It shows you how the pressure varies from place to place along with wind etc updated every few seconds. It also shows why Blake in Montana should probably not use California Ted's number. You were kidding weren't you Ted? I was not certain because I did not see any of these
.
I have been wondering where to get accurate readings to calibrate my barometer. This gives all the weather info updated every few seconds at many local stations. It shows you how the pressure varies from place to place along with wind etc updated every few seconds. It also shows why Blake in Montana should probably not use California Ted's number. You were kidding weren't you Ted? I was not certain because I did not see any of these
.What am I missing Bob ? I thought the link showed
barometric pressure of 30.09 at Tipi Village Sub-Division, Red Lodge, Montana,Elevation: 5960 ft updated every 15 minutes or so ? Isn't that the pressure being read by a barometer at the site ?
barometric pressure of 30.09 at Tipi Village Sub-Division, Red Lodge, Montana,Elevation: 5960 ft updated every 15 minutes or so ? Isn't that the pressure being read by a barometer at the site ?
BobV Go to this link for Red lodge ,Mt
weather underground. http://www.wunderground.com/cgi-bin/findweather/getForecast?query=red+lodge%2Cmt You must ues it all including that which is not blue. Sorry that link won't copy and paste here .
weather underground. http://www.wunderground.com/cgi-bin/findweather/getForecast?query=red+lodge%2Cmt You must ues it all including that which is not blue. Sorry that link won't copy and paste here .
My mistake Ted
I thought you were giving him local California. I do see that the pressure changes over small areas in short time however so if anyone wants to acurrately calibrate they should probably do it in real time. I see that there is a station in Port Townsend where I stop frequently so next time I'm there I plan to bring up the site and set my barometer.
I thought you were giving him local California. I do see that the pressure changes over small areas in short time however so if anyone wants to acurrately calibrate they should probably do it in real time. I see that there is a station in Port Townsend where I stop frequently so next time I'm there I plan to bring up the site and set my barometer.
Long links fix
If long links don't work, in the text of a message, just paste 'em in the "Want to add a link..." box below the text input box. Simpler, too. It comes out as "Related Link" below your text message.
If long links don't work, in the text of a message, just paste 'em in the "Want to add a link..." box below the text input box. Simpler, too. It comes out as "Related Link" below your text message.
Whew !, Thought I'd had another of those
"moments" and done something like used sea level 'cause 30 inchs did seem high for almost 6000'.
"moments" and done something like used sea level 'cause 30 inchs did seem high for almost 6000'.
Still stumped
Thanks to all for the info. I've got Ross's link up, I've got the back off of the barometer and I've attempted to adjust it via a small screw. It is currently reading 30.21 inches, the website says 30.03. The adjusting screw, when turned clockwise, will make the needle move to a higher number. When I back it off, counterclockwise it will return to 30.2 or there abouts. If I keep turning, counterclockwise, the the screw will eventually fall out but the needle will not go lower. Any thoughts? On another issue, how often do you adjust these things? I am a trailer sailor and sail on a variety of lakes and reservoirs. Is it necissary to take the thing off the wall and adjust at each site? It may seem like a little thing but there is already much to do to get the boat from trailer to water, and I doubt that I will be taking the time to unbolt it from the bulkhead to get at the adjusting screw. If so it may indeed end up being a merely decorative item, at least for weekend lake sailing. One more question, I found a similar Barometer listed on ebay, and it was described as "compensated". What does that mean?
Thanks to all for the info. I've got Ross's link up, I've got the back off of the barometer and I've attempted to adjust it via a small screw. It is currently reading 30.21 inches, the website says 30.03. The adjusting screw, when turned clockwise, will make the needle move to a higher number. When I back it off, counterclockwise it will return to 30.2 or there abouts. If I keep turning, counterclockwise, the the screw will eventually fall out but the needle will not go lower. Any thoughts? On another issue, how often do you adjust these things? I am a trailer sailor and sail on a variety of lakes and reservoirs. Is it necissary to take the thing off the wall and adjust at each site? It may seem like a little thing but there is already much to do to get the boat from trailer to water, and I doubt that I will be taking the time to unbolt it from the bulkhead to get at the adjusting screw. If so it may indeed end up being a merely decorative item, at least for weekend lake sailing. One more question, I found a similar Barometer listed on ebay, and it was described as "compensated". What does that mean?
Blake, What you really need to know is the trend.
Is the barometric pressure rising or falling? A falling barometer indicates the approach of a low pressure system and posibly stormy weather. A rising pressure indicate the approach of a high pressure system and the liklyhood of fair weather. Since you trailer sail you generally are concerned with just one day at a time. You may need to take your barometer to an instrument technician and have it reset for your altitude. If you examine the works, you can see that the needle is mounted on a gear shaft and the movement of the bellows pushes a rack that engages a pinion gear that turns a shaft that moves the needle. If you slip the rack one tooth it will change the position of the needle. Pick a barometer up at a yard sale and disect it to see how it works.
Is the barometric pressure rising or falling? A falling barometer indicates the approach of a low pressure system and posibly stormy weather. A rising pressure indicate the approach of a high pressure system and the liklyhood of fair weather. Since you trailer sail you generally are concerned with just one day at a time. You may need to take your barometer to an instrument technician and have it reset for your altitude. If you examine the works, you can see that the needle is mounted on a gear shaft and the movement of the bellows pushes a rack that engages a pinion gear that turns a shaft that moves the needle. If you slip the rack one tooth it will change the position of the needle. Pick a barometer up at a yard sale and disect it to see how it works.
Don’t worry about adjusting it.
Blake, Don’t worry about adjusting it. The rate of change and if its going up or down is how you tell what’s coming as far as weather goes. The absolute pressure isn’t that impotent unless you are comparing readings among other stations or using a barometer to keep a record. If its going up, enjoy the sailing and if it’s going down look out for a change because some bad weather is probably coming your way and the faster it drops the more severe the wind will be when it gets to you. Compensated just means the works are automatically adjusted for temperature changes. All the best, Robert Gainer
Blake, Don’t worry about adjusting it. The rate of change and if its going up or down is how you tell what’s coming as far as weather goes. The absolute pressure isn’t that impotent unless you are comparing readings among other stations or using a barometer to keep a record. If its going up, enjoy the sailing and if it’s going down look out for a change because some bad weather is probably coming your way and the faster it drops the more severe the wind will be when it gets to you. Compensated just means the works are automatically adjusted for temperature changes. All the best, Robert Gainer
Great info
Thanks to all. I'm going to take Ross's advice and just worry about one day at a time!
Thanks to all. I'm going to take Ross's advice and just worry about one day at a time!
handheld weather instruments
speedtech skymaster, $171 ambientweather.com, floats. Has a barometer and wet bulb. Also measures humidity, dew point, and heat stress index. The barometer and temperature screens also show graphs of past trends. The kestrel 4000 for $329 comes with a docking station that can be hooked up to a laptop and has graphic records for barometer, temperature, etc. There is also a skywatch explorer for $52/ambientweather.com. If you want to take the guesswork out of weather indicators, temp, barometric pressure, wind speed and memory of past trends, handhelds may be very useful. Practical Sailor may 2007 has a good article with pros and cons of several units. Most have 1 year warranty and some are warranted for 2 years.
speedtech skymaster, $171 ambientweather.com, floats. Has a barometer and wet bulb. Also measures humidity, dew point, and heat stress index. The barometer and temperature screens also show graphs of past trends. The kestrel 4000 for $329 comes with a docking station that can be hooked up to a laptop and has graphic records for barometer, temperature, etc. There is also a skywatch explorer for $52/ambientweather.com. If you want to take the guesswork out of weather indicators, temp, barometric pressure, wind speed and memory of past trends, handhelds may be very useful. Practical Sailor may 2007 has a good article with pros and cons of several units. Most have 1 year warranty and some are warranted for 2 years.
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