GPS may not be reliable.

[Kevin Bladsacker]

A new system

Maybe we should apply some federal money for a system for citizens and ban it from being attacked by our own military. I would think that the benefits to transportation justify the expense. Look at what the Interstate systmen did for trucking and recreation. We didn't get that until they wanted to move tanks around quicker.

 

[abe]

I think if a Koren Nuclear Warhead was heading

towards our family's town, I would't be to upset if our government does something with GPS to either miss the target....or better yet send it back where it came from. Get real people, itsa new world.abe

 

[eds928gt]

During a National emergency - all bets are off.

First, if the government declares a "National Emergency" - ANYTHING (public, private or otherwise) that can be used against this country can be controlled by the government.Second, presently, the government is running a huge deficit. Spending yet more tax payor dollars on a civilian GPS system is not likely to occur anytime soon.~ Happy sails to you ~ _/) ~

 

[Tim C350 April IV]

Could Turn Out the Lights, Too.

I suppose in the right kind of emergency situation, the lights/electricity could be turned out too. Makes it pretty tough to find a target in the dark. Think back to what you've read (or seen in movies) about WW2 - mandatory blackouts, blackout lights on cars and trains, etc.Or turn off the lights at intersections. Did you know that many citys have the capability to manipulate the lights at intersections to facilitate the flow of emergency vehicles? Happens all the time.Bottom line is that those that we elect and empower to provide for the common good and protection of our nation are also to be provided with the means to do it. Even if it means minor (or not so minor) inconviences. Recreational boaters complaining about temporarily losing GPS navigational assistance probably rank near the bottom of the considerations the gov't thinks about when examining a GPS shut-down option. Think commerce, safety (as in airlines), and other things more important to the functioning of our country than recreational boating.Tim "like my GPS, but can live without it" BroganApril IV C350 #68Seattle47 degrees 40' 40" N122 degrees 24' 33" W

 

[Fred Ficarra]

Stu that's 'gov-speak'

Improving performance by turning it off, that is. Remember when the Post Office said they would improve service by slowing delivery?And Patrick, recall that a GPS signal is only 5 watts. Thats easy to jam even for malfunctioning consumer electronics, not to mention one of those Navy E6 jammer Prowlers based in your backyard. Whats cool is when they fly one over cities in Iraq. It triggers some of the garage door activated bombs that the terrorists have built. Many when they are still in the terrorists home, or car, or,,

 

[Kevin Bladsacker]

Sextent accuracy

Good point about the sextant. Which ones are accurate to within 15'?

 

[Stu Jackson]

Merry Holidays to All

Thanks for all the responses. I've learned a lot. Phil, Patrick (thanks for the detailed post), and Rich summarized it best, and the variety of opinions is what this (and this country) are all about.I agree that those in charge are there to defend us and should be able to utilize all means at their disposal to do so.I use paper charts and my eyes and ears. Everything else is backup.I agree with the post about "govt. speak." I abhor lies, especially when they are as twisted and obvious as this one. My initial comment was on the wording of the announcement, and then the futility of having to absorb repeated written and spoken flip flops became apparent.Why spin something from the get-go? Why not just tell the truth and not say black and white in the same sentence?Darn, they've even politicized boating. Some will say I politicized this thread. If you think I did, I apologize.If not, (or even so), I sure enjoyed reading ALL of your thoughts and opinions, in each and every one of your notes.Please remember, it's NOT they (the govt.) and WE (boaters). Please also remember that WE, as citizens, PAID FOR ALL THE STUFF. It's just as much OURS. There's no reason not to have an opinion. And we are able to discuss it with humor, wit and wisdom. That's what it's all about.Thanks again and Happy Holidays,Stu

 

[Ed]

Sextant accuracy

Depends on the user. In calm seas and clear skies, a good sextant with a vernier scale, used by someone who is very careful can be accurate to about 50'. However, on the high seas it is more likely that the accuracy will be about 500' or so. That's usually more than adequate unless you're trying to navigate in a channel. However, there should be channel markers in a channel, and DR becomes far more useful when one can actually see land for use as reference points.~ Happy sails to you ~ _/) ~

 

[Gord May]

Celestial Accuracy ?

ED says: "In calm seas and clear skies, a good sextant with a vernier scale, used by someone who is very careful can be accurate to about 50'. However, on the high seas it is more likely that the accuracy will be about 500' or so."The importance of multiple navigational methods cannot be overstated. Notwithstanding, Celestial Navigation cannot be used for Coastal Piloting - it’s simply too inaccurate!Practical Manual Celestial Navigation provides an average ERROR in position on the order of 1.5 to 2 nm. Although not very accurate, by comparison with modern Electronic Navigation Equipment (GPS), this is more than adequate for maintaining a Running Fix (on offshore passages), or even for locating an Island or City. There are several factors that introduce errors into a Celestial Fix, including:~ Navigators Skill - ie: manual dexterity, and the moving platform (small boat)~ Sextant error~ Time error... etcSEXTANTS:An error of 1 minute of arc will introduce a navigational error of 1 nautical mile, and an error of 1 second will result in an error of about 100 feet.An excellent sextant will exhibit errors of less than 10 seconds of arc (<1,000 foot error), whereas cheap plastic sextants commonly manifest errors of as much as 5 minutes (resulting in nav’ errors of 5 nm).Even an inexpensive plastic sextant costs almost $200, and a basic aluminum alloy one is about $500. Some of the best sextants are made by C. Plath and their prices range from $1500 to over $3000. Japanese sextants made by Tamaya costing from $1400 to over $2000 are another excellent choice.TIME:Accurate time is also important ,because each second of time error introduces a navigational error of over 1,500 feet (four seconds of watch error can result in navigational errors of about 1 nm). It’s worth noting that the “US Sailing” Certification in Celestial Navigation only requires that the graduate “ will have mastered the techniques of open ocean position fixing using sextant and timepiece - ie: Plot a running fix from two celestial sightings separated by at least one hour, which is accurate within FIVE MILES.”A great article from Bluewater Charts - “GPS is Great, But...” - By Peter F. Prowanthttp://www.bluewaterweb.com/Newsletters/9-01gps.aspFrom Ocean Navigator Online (free) “Confident Celestial” - by Gregory M. Walsh http://www.oceannavigator.com/site/csrv/content.asp?id=1300“Necessary Nav Nnowledge” - by Andrew Howe http://www.oceannavigator.com/site/csrv/content.asp?id=718

 

[Fred Ficarra]

That goes with the reasons we didn't study

celestial. For our travels, we would be within a day or two sail of land, at the furthest. Our buddy boat owners took celestial because they were headed across the Pacific. Good thing too. Their Satnav died mid ocean on the way to the Marquesas. They didn't have GPS back then. Too expensive. I had it but it was $2000. That's two thousand. (Garman GPS 100) It survived a lightening strike. Sorta. We had to bypass the NEMA interface to get a position reading. We also had a Loran backup and Radar too but they were both dead. I'm rambling, sorry. Back to celestial. My buddy and his wife had to go to class twice a week for a couple of months to learn the stuff. Then they had homework too. I felt my time was better spent outfitting our boat.

 

[Tom S.]

Where has everyone been !?!

They've been messing with GPS signals and accuracy in certain areas for year. Even before 9-11. I recall going down towards the East river from LI sound for the July 4th 2000 Op Sail and noticing my GPS was way, way off. Only after I got down to NY Harbor did I start to realize why. There were scores and scores of all types of Naval Vessels in the harbor and dignitaries scheduled to visit.When I went down to "Sail For America" one year after 9-11 they did the same thing. They do it all the time, I'm amazed that everyone is so surprized.Everytime that it has happened to me I recall thinking something wasn't right (I had the autopilot being driven by the GPS -- I single hand often and my helper - Otto the autopilot - helps me steer the longer trips - Ok back to my story) When I was going west towards execution rock I kept thinking "Aren't I supposed to be north of that bouy ?" After a minute or two and checking and rechecking it was a like a lightning bolt hit me in my head ! YIKES *yks I'm on the wrong side of this marker !!!! I spun the boat around real quick !! I calculated that in about 100 yards I was going to run aground on some rocks there. I'm glad my eyes and other senses were backing up my GPS.Lesson is -- GPS is a navigational "AID" Just like all other navigational AIDS, it is not flawless and there are no guarantee's. Even bouys can move due to storms, too many skippers are getting more and more complacent and loosing their natural instincts and skills and expecting the government and electronics to make sailing/boating (Life??) a push button experience with no risks. Hey I am the first person to say that my electronics greatly enhance my sailing experience (it does! - and I have a lot of goodies), but to rely on them too much for sailing is not prudent -- any way you never know when they are going to break down anyway.I guess my last question might be - How often are they screwing with the signals in any given area. Every other day or once a month or so? I can expect it messed up once in a while, but too often would be a pain. Personally when they wanted to mess with GPS, I'd rather they shut off all the signals and my GPS would beep "No Signals Found" and I'd know to take over and keep a closer watch. Its those foogy days when 300 yard errors injected that I don't know are being injected that bother me.

 

[SailorGuy]

GPS - DOD Tool

I rarely contribute here, but I do gain a lot of valuable knowledge reading other's suggestions and ideas. However I do feel compelled to address some of the comments being made on this subject. To say that I know something about GPS and the tools that it provides would be an understatement. However, to assume that this is a "lobbying" situation, or that the discussion should be taking place so that boaters can possibly sway the government on this "tool" is an overstatement so far to the extreme that it is laughable. GPS was not placed into service so that recreational boaters could keep up with their position without proper training and understanding of basic navigational skills. GPS was placed into service in order to provide the Department of Defense a means to defend the United States, plainly and simply. It is just that - a tool - and can be and WILL be disabled when and if a situation arises that warrants the system to be disabled. Therefore, if you don't know your way home using the before-mentioned basic navigational skills, it's probably best that you stay home. It's much safer there. Rich and Phil, I beg to differ with you. You imply that a certain poster's obvious political statement should be allowed because this discussion is one that needs to be taking place since boaters need GPS in order to navigate the world's oceans. You are wrong. GPS is and was a system put into place for the much larger picture. You have been allowed to use it, and will likely continue to be allowed to use it, but if an administration decides that for the safety of our country that it is necessary to make the system unavailable - either temporary or permanent - it will be made unavailable. And it won't matter if there is a republican holding the top office, or a democrat holding the top office.

 

[Fred Ficarra]

Hard to argue with SailorGuy

The trouble with shutting down the system for national security is the collateral damage to the civilian population that had grown to rely on it. It's now sorta like the internet only the loss of GPS will certainly be more dangerous than the loss of the web.The events of 9/11 were carried out by religious zealots looking to score 70 or so virgins in their heaven. Their leaders have raised the reward to 100 virgins in order to get new recruits. And as long as these un-evolved beasts have access to weapons as inexpensive as a box cutter, shutting down GPS is not likely to happen. Besides, the Europeans are building a civilian system. Why? I suspect feelings of self worth. Just like the Chinese going to the moon.

 

[John Baumgartner]

OK, I'll have to add my $.02

I have used GPS or as I knew it back then NAVSAT since 1974, when I was an enlisted Navagator onboard subs. At that time it was Top Secret. Once the cat is out of the bag and many multi-million if not billion of dollars are at stake it would be very very hard for the goverment to retract it. As usual in this country money talks and bull walks. Baums Rush

 

[Bob Todd]

Have we gotten so dependent upon electronics...

...that crap like this is cause for alarm? Perhaps it will encourage the dumb and the lazy to finally learn how to read a chart.Yeah...I have all the toys, but I use them to augment the good old fashioned way. I see too many people relying so heavily on technology that they couldn't find their way off the mooring without it.Just my two-cents.Happy Holidays to all!Cheers,Bob