Why a barometer is a good thing on a boat

[Mark Mc]

Barometers are good for more than the clocks you see in the Westmarine Xmas catalog.

Look at the plot for wave height for last few days at 46050, then look at the plot for atmospheric pressure for the same time period.

[Phil Layer]

Good one, Mark. Thanks for the demo.

[Sea Jypzee]

Wow, impressive. Very good demo Mark.
[img]graemlins/applause.gif[/img]

[edsr]

Mark - A few questons please about your barametic observations.

How do you keep a record while on your boat? My understanding is that a number of recordings are needed to plot how the barometer is changing so that you can develop a graph as you illustrated, is that correct?

What intrument can take the salty environment and the pounding a small boat gets?

edsr

[Bait O' Eggs]

Ed I know you have the same Garmin 76Smap GPS I have. It tracks the barometer and plots the points on a graph continously for 8 hours, even with the unit turned off. :shocked: The unit is suppose to be both waterproof and float. (can you tell I like it :tongue: )

Just turn it on, hit page a few times until you have the right page and you can see what the barometer is and has been doing. You can even set it to a couple different units

[Mark Mc]

Hi Ed,

My personal experience is only with the good old-fashioned type like this:



You set the little arrow at the present pressure, and you check once in a while to see if it changes. Significant change (usually falling) is what you keep your eye out for.

While getting this image from a marine catalog, by searching on "barometer", several electronic gadgets came up too, such as the one mentioned by BOE. I still think there's merit to the old-fashioned kind that doesn't need batteries, and it's easy to look at it often when located near the helm.

edit / p.s. - yes, I suppose a graphing function would be nice for multi-day trips, to track gradual changes. But for a day trip, you're really interested in a rapid change over just a few hours, which tells you that something is going to happen real soon and you'd better get off the water.

[ 10-10-2003, 01:35 PM: Message edited by: Mark Mc ]

[edsr]

Once, some years ago I actually witnessed the barometer needle fall as I was watching. My memory fails me as to how much it fell but an inch or an inch and a half is what I remember. What a roller coaster ride the weather was that day. Fortunately we were inside and not on the water with the rain, wind, and lightning! We thought the barometer was broken and then slowly it began to stabilize and it returned to a more normal position. That all happened in about an hour or less. I haven't ever seen anything quite like that since.

Hey - BOE - Yeah, I knew the 76s has a barometer but with my warped thinking I just figured it would be useful if I was mountain climbing. Duh!

edsr