# Risk of GPS loss



## Pamlicotraveler (Aug 13, 2006)

The Chinese government confirmed today that it had conducted a successful test of a new anti-satellite weapon by shooting down one of their own satellites. It should serve as an alert to navigators that a functioning GPS system can't be assumed. 

It made me move "learn celestial navigation" higher up my to do list.


----------



## capt.stu (Oct 5, 2004)

If it gets to the point that the Chinese are shooting down our satalites, I don't think it will matter much where you are going. Best to just stay at sea.

Stu


----------



## JagsBch (Jan 19, 2007)

WOW~!! I guess we can thank Bill Clinton for that.


----------



## sailingdog (Mar 19, 2006)

If the Chinese start shooting down GPS satellites, then small islands in the south Pacific might be the best place to head to...and having your sextant along is probably a good idea.


----------



## Giulietta (Nov 14, 2006)

oh my God...the russians are coming...the russians are coming....

Chil out.....we still have to wait for the US to Invade France...


----------



## TSOJOURNER (Dec 16, 1999)

JagsBch said:


> WOW~!! I guess we can thank Bill Clinton for that.


Nixon is more like it. But if GPS satellites start being shot down, there will be more to worry about than your chart plotter.


----------



## hcooper (Feb 24, 2000)

*GPS loss*

Nixon was not the one, it was WJ Clinton that also invited them aboard our boomers and fast attack subs. Nevertheless, that is past history. There is always basic old charting and even the old compass. Not all bad. Just had a friend that was sailing from Port Aransas, Texas to Isla Mujeres, when his whole system went down about 200 nm out. He actually made it using the compass and some good chart work. The Chinese had nothing to do with it.


----------



## T34C (Sep 14, 2006)

JouvertSpirit said:


> Nixon is more like it. But if GPS satellites start being shot down, there will be more to worry about than your chart plotter.


You have got to be kidding. We didn't even have GPS then. Or the guided missles to shoot down a satelite.


----------



## Fstbttms (Feb 25, 2003)

JagsBch said:


> WOW~!! I guess we can thank Bill Clinton for that.










There's one in every bunch.


----------



## sailingfool (Apr 17, 2000)

As the PO of my current boat completed their shakedown cruise from New England to Bermuda, they arrived in the nieghborhood of the island with no engine and not a drop of battery power, due to a series of little surprises that compounded to produce four dead batteries. They did have a sextant and knew how to use it, so they sailed without too much excitement directly into St. George.

I think anyone going offshore relying on GPS is asking for trouble...


----------



## TSOJOURNER (Dec 16, 1999)

If you get lost, just pull in somewheres and ask directions!
Sorry, had to.
Loran is still up too, for near shore stuff.


----------



## tigerregis (Nov 24, 2006)

Indicating that one has the ability to do something might ruffle a few feathers, but it is not as intimidating as IEDs or suicide bombers that one can't see until it is too late. Brinkmanship wasn't invented in Peking.


----------



## TSOJOURNER (Dec 16, 1999)

T34C said:


> You have got to be kidding. We didn't even have GPS then. Or the guided missles [sic] to shoot down a satelite [sic].


Perhaps you would like to back up your statement with some references as to the GPS time line.


----------



## tdw (Oct 2, 2006)

Giulietta said:


> oh my God...the russians are coming...the russians are coming....
> 
> Chil out.....we still have to wait for the US to Invade France...


Russians, aren't they good guys now ? You know, like Tony Blair's newest bestest friend Muamar Gadaffi. The Chinese, on the other hand are vicious commo dictators .......Yeah, yeah, I know G, "chill out TD". You'd be right and my hearts just not in it today. I'm going back to sleep.


----------



## poopdeckpappy (Jul 25, 2006)

Giulietta said:


> Chil out.....we still have to wait for the US to Invade France...


Then where are we gonna get our fries ??


----------



## Valiente (Jun 16, 2006)

sailingdog said:


> If the Chinese start shooting down GPS satellites, then small islands in the south Pacific might be the best place to head to...and having your sextant along is probably a good idea.


Astra IIIB, Freiberger Drum Sextant, an NC-77 celestial calculator, everything Bowditch and Mary Blewett ever wrote and lots and lots of plotting sheets live aboard.

Let's face it, unless you like to pretend you're in a private episode of "Star Trek", once offshore, you can get in valuable mental time plotting and fixing via sextant and DR. By all means *confirm* if you want via GPS (unless the BBC tells you some ******* war has broken out), but the pleasure of navigating to a distant port via celestial is not to be sneered at. I personally quite enjoy using even a simple hand-held compass to take bearings and to determine my speed without reference to the knotmeter (the impeller is often fouled) or the GPS. Keeps my mind alert.


----------



## JagsBch (Jan 19, 2007)

I just watched a special on Nova, Norwegian Ronald Amundson 1903 journey in the arctic. His compass was useless at the poles, with only his sextant, Amundson was the first explorer to cross the Northwest Passage. Amundson was also the first explorer to reach south pole. 

Between the Chiness shooting down satelites and impending polar shift on the horizon thrashing our GPS and compasses, how on earth can anyone find comfort sailing off into the blue without a sextant?


----------



## seabreeze_97 (Apr 30, 2006)

Isn't GPS used by everyone, worldwide? If anyone wants it down, they have much worse in mind (but I imagine they'd rather use own own system against us) and I'd have to agree being at sea might be safer in general. Working the mind with older methods is a great way to stave off cruisheimers, and keeps one sharp in the event of systems failure. Doesn't make sense to down GPS anyway. Our armed forces would simply revert to the previous methods using laser guidance and continuous calculating impact computers, as used in the first Gulf War....plenty accuracy there. If nothing, GPS could be the space-based "Twin Towers" symbolically speaking, so I'm glad the gov't opted to beef up Loran, instead of shutting it down.


----------



## cardiacpaul (Jun 20, 2006)

Jovert...
" beginning with the Transit system in 1965, which was developed to meet the navigational needs of submarines carrying Polaris nuclear missiles. These submarines needed to remain hidden and submerged for months at a time, but gyroscope-based navigation, known as inertial navigation, could not sustain its accuracy over such long periods. The Transit system comprised a half-dozen satellites that would circle the earth continuously in polar orbits. By analyzing the radio signals transmitted by the satellites--in essence, measuring the Doppler shifts of the signals--a submarine could accurately determine its location in 10 or 15 minutes. *In 1973, the Department of Defense was looking for a foolproof method of satellite navigation. A brainstorming session at the Pentagon over the Labor Day weekend produced the concept of GPS on the basis of the department's experience with all its satellite predecessors. The essential components of GPS are the 24 Navstar satellites built by Rockwell International, *each the size of a large automobile and weighing some 1,900 pounds. Each satellite orbits the earth every 12 hours in a formation that ensures that every point on the planet will always be in radio contact with at least four satellites. The first operational GPS satellite was launched in 1978, and the system reached full 24-satellite capability in 1993."


----------



## JagsBch (Jan 19, 2007)

There are only 24 to shoot down? Size of a large automobile? Talk about a nice target. If you can plot within 1 to 2 miles with a sextant, why on earth would every blue water sailor NOT have a Sextant on board. I am wondering what do you suppose the percentae of cruisers who don't have or know how to use a sextant 25, 50, 75% or greater? To me it has got to be one of the ultimate instruments for peace of mind.


----------



## Goodnewsboy (Nov 4, 2006)

Just an opinion, but anyone preparing for an ocean cruise ought to be equipped for and capable of at least local apparent noon and latitude by Polaris sights. It isn't rocket science and it really does work. No batteries, electronics, or satellites required.


----------



## Giulietta (Nov 14, 2006)

tdw said:


> Russians, aren't they good guys now ? You know, like Tony Blair's newest bestest friend Muamar Gadaffi. The Chinese, on the other hand are vicious commo dictators .......Yeah, yeah, I know G, "chill out TD". You'd be right and my hearts just not in it today. I'm going back to sleep.


TD this was a joke where I was remembering a movie that was made many years ago, where a russian sub beached in the US and all town went crazy.....over nothing

It was a way to say...you guys worry with things that need nothing to worry about..

and from there this discussion went on to sextants, and now its almost a given that most ocean goes don't use one...and...well forget it..


----------



## camaraderie (May 22, 2002)

Ha...going to meet Armageddon with a sextant! I think I'll dig a fallout shelter in my backyard as those islands in the south pacific will be under water with the icecap melt!....then frozen over with nuclear winter and you won't be able to take any sunshots for a few decades either! <g>


----------



## T34C (Sep 14, 2006)

Cam- So chuck the sextant for a pair of ice skates!!!


----------



## Giulietta (Nov 14, 2006)

Hey, according to some SOFA SAILORS here, he doesn't even have one....


----------



## camaraderie (May 22, 2002)

Giu...You're right...I wouldn't be caught DEAD with one!! <g>


----------



## Giulietta (Nov 14, 2006)

camaraderie said:


> Giu...You're right...I wouldn't be caught DEAD with one!! <g>


Cam, please what is a Sextant??? Do I need one??? Is it heavy???  

Also, a friend of mine has these papers with my country drawn on them, a lot of numbers and such, do we need those too??? I have a very good road map, will that do???


----------



## PBzeer (Nov 11, 2002)

De Gama didn't have charts, why do you need 'em Giu?


----------



## Giulietta (Nov 14, 2006)

PBzeer said:


> De Gama didn't have charts, why do you need 'em Giu?


Absolutely right!!! Well they did have some and drew as they went....

However, he had a Sextant and an Astrolabio!!!

I bet he did'nt know how to use them...Columbus didn't!!!


----------



## Johnrb (Sep 21, 2002)

"De Gama didn't have charts, why do you need 'em Giu?"

LOL for the day.


----------



## pigslo (Nov 22, 2004)

please remember that Columbus also thought he was in India and so named the natives of North America Indians.
pigslo


----------



## JimHawkins (Aug 25, 2006)

Giulietta said:


> TD this was a joke where I was remembering a movie that was made many years ago, where a russian sub beached in the US and all town went crazy.....


What do you mean that was a movie? Wasn't it on CNN? I thought it was a terrorist attack.


----------



## Zanshin (Aug 27, 2006)

Luckily the sub didn't beach on a French shore, otherwise the country might have capitulated.


----------



## Giulietta (Nov 14, 2006)

JimHawkins said:


> What do you mean that was a movie? Wasn't it on CNN? I thought it was a terrorist attack.


   Yes a movie, and a very funny one...If I remember it was called "the Russians are coming""..... can't remember...anyone??


----------



## Pamlicotraveler (Aug 13, 2006)

Columbus did use celestial navigation (a quadrant)...but he wasn't too good at it. He landed in Cuba and thought it was Virginia (been there, done that)


----------



## Giulietta (Nov 14, 2006)

Zanshin said:


> Luckily the sub didn't beach on a French shore, otherwise the country might have capitulated.


I knew trhat this thread, like most I have been, end up in France  

Look my good American friends, just come over and invade them, please, please???

Then you can have their French wine and fries and kisses for free!!! Sorry but you also get their women


----------



## xort (Aug 4, 2006)

The Chinese Are Coming! The Chinese Are Coming!


----------



## Giulietta (Nov 14, 2006)

xort said:


> The Chinese Are Coming! The Chinese Are Coming!


are you in the US???? because froim what I see when I travel there is:

THEY'RE ALREADY HERE, THEY'RE ALREADY HERE!!!!


----------



## Idiens (Jan 9, 2007)

Well done the Chinese, they joined the we-can-do-it-too club, to the dismay of existing members. I wonder when they will seriously get into yachting? - now that's a club that I am in....


----------



## TSOJOURNER (Dec 16, 1999)

Giulietta said:


> Cam, please what is a Sextant??? Do I need one??? Is it heavy???
> 
> Also, a friend of mine has these papers with my country drawn on them, a lot of numbers and such, do we need those too??? I have a very good road map, will that do???


After loosing my chart plotter and having no paper charts, I used a road atlas to cross the gulf of Alaska. Ended up right where I wanted to be.
I always carry paper now thou. Lesson learned.


----------



## Giulietta (Nov 14, 2006)

wildcard said:


> After loosing my chart plotter and having no paper charts, I used a road atlas to cross the gulf of Alaska. Ended up right where I wanted to be.
> I always carry paper now thou. Lesson learned.


Listen, I kid you not, I have a very very good friend that has a little racing boat called a Grand Surprise (French  ), and he cruised for 4 months with his wife, and 2 daughters all over Portugal, and Spain and Med, with just that.....I does not have a sea chart, GPS anything......helps he knows where he is, but that's it...Last year, he got one of those bycicle GPS's and that was it, he said he never used it!!! He still goes and returns in his litle 26' sled. Inside this boat is samller than a 2 person tent.

He has been sailing for a while also, and get this he is the manager for Jaguar Portugal... he is just a simple guy.....with a simple life...


----------



## wind_magic (Jun 6, 2006)

I think the biggest threats w/ GPS in sort of descending order are ...

Main threats ...


Over dependence - thinking GPS IS navigation, it isn't. It is just a really precise fix. Not cultivating alternative means of getting a fix because "GPS is so reliable".
Electrical - total dependence on wired GPS chart plotters that need a complex functioning electrical system to support them.
Battery - lack of batteries for the hand held GPS.
Mis-identification - blindly doing what the GPS says against common sense, spelling the name of the landmark wrong, fat fingering the coordinates when you type them in, etc, and ending up in trouble.
Losing handheld - over the side, buried in dirty laundry, forgotten on shore, etc.
Breaking plotter - screen stops working, corrosion, etc.
Wrong charts - having the wrong charts for the area, or fat finger the setup of the plotter, screwing up the plotter configuration, etc.
Fatigue - try making sense of a GPS when you haven't slept for 48 hours, then try paper charts, much easier.
General user errors - random acts of stupidity, using GPS headings as compass headings, etc.
Zoom errors - Having the chart zoomed in or out to a point where it looks like what you are seeing but is actually zoomed wrong so all the hazards are on the wrong scale and you are actually looking at the chart completely wrong.
Swirling - looking at a chart plotter instead of looking at your destination and feeling the wind on your face, can lead to "swirling" in a spiral around your target as the wind acts against your heading instead of standing in the cockpit and feeling the wind and seeing the obvious.
Theft - ooh, pretty gadget, think I will take it home with me ...
Crapware - increasing reliance on less rigorously tested and developed software, poorly written chart plotter software, software development by technology companies that don't actually know anything about how the device gets used on a boat, etc.
Sizzle - buying the prettiest thing instead of the best thing, or buying the "very best top of the line" and setting out to sea under the assumption that it is going to do everything you need because "it's the best".
Expense - spending so much on one gadget that you can't afford to have backup plans, can't afford paper charts to fall back on, etc.
Discontinued - having older (even just 3 years old) plotter that you can no longer get charts for because the company stopped supporting it, what if that happens at an inconvienent time for you ?
Inexperience - buying the latest gee-whiz but not having any idea how to actually use it, or having to go to the manual during a critical time to figure something out, relying on statistics and important facts that were calculated using math and methods that you do not understand or have the background for, etc.

Secondary threats ...


Wrong datum
Overly precise - just because your GPS is correct within 10 feet doesn't mean your chart is.
Nothern exposure - high latitudes increase error.
Manufacturing/design problems - a few GPS devices have simply been wrong.
Exotic errors - electrical mischief, software glitches, acts of God, etc.
Localized GPS blackouts - off the coast of Yemen for example, jamming ?
Sensitivity - it used to be that all GPS units had big antennas and picked up a good signal, but many now have such small antennas that there are conditions under which you cannot get a fix even standing out under a full sky.

Never gonna happen threats ...


U.S. Military turning the system off, introducing error, etc.
Chinese people blowing up GPS satellites
Tooth faerie cooking the satellites and enjoying them with soy sauce, etc.


----------



## pigslo (Nov 22, 2004)

We were on our way from Port Arransas Texas to Houston in the ICW when we ran aground. My navigator ran to the laptop hooked into the gps to figure out what happened. The gps showed us 1/2 mile away from where we were because the batteries were coincidentally sputtering out just then. It took a minute of study to figure out the gps was wrong during which time the misinformation helped to put us further aground. By the way, you can pry a 36 foot 17,500 lb boat out of the mud with a whisker pole if you have to. Gps is just one tool in the arsenal and common sense and a backup should always prevail on any boat system.
pigslo


----------



## Tartan34C (Nov 21, 2006)

Wind Magic said, “Nothern exposure - high latitudes increase error.”
Why is that? I thought the system used satellites in polar orbits so that the whole world was covered to the same degree.
Thanks,
Robert Gainer


----------



## TSOJOURNER (Dec 16, 1999)

PARANOYA STRIKES DEEP---INTO YOUR MIND IT WILL CREEP--if you rely on gps, my advice,stay safe at home and watch national geographic on tv....jt


----------



## KeelHaulin (Mar 7, 2006)

Idiens said:


> Well done the Chinese, they joined the we-can-do-it-too club, to the dismay of existing members. *I wonder when they will seriously get into yachting? - now that's a club that I am in....*


In case you have not heard... 
http://www.americascup.com/en/americascup/teams/index.php?idIndex=&idContent=1876


----------



## camaraderie (May 22, 2002)

I absolutely rely on GPS. And I always have TWO on. 
What I don't rely on is *chart plotters* even though I have one. Wind seems to link the two. They are not the same.
GPS tells me my Lat and LONG more precisely and accurately than anything else ever invented and in all kinds of weather and day or night. If my 2 active GPS's agree.... I am exactly where they say I am on my paper charts. If they ever decide not to agree (hasn't happened in many years of cruising) I will stop the boat and take stock and probably break out one or more of my reserve units. The only thing I rely on more is my EYES. The combination of the two is unbeatable. 
Example: Sailing past St. Vincent...the GPS plot on my paper chart AND my chartplotter had me well offshore in deep water. Everything agreed but the depthsounder which said 20 feet of water where there should have been hundreds of feet. All stop! Looked around... land was where it was supposed to be...both GPS's agreed. Broke out a third and it agreed. Shortly thereafter the depth sounder went off soundings. Guess it was a whale or something. Point is...you sometimes need a combination of things to figure out a situation but it is tough to beat the combination of a GPS position, a good chart and your eyes paying attention to all they should.


----------



## sailaway21 (Sep 4, 2006)

The transit system utilizes satellites in polar orbit and so, in addition to rising and setting, their declination varies. The system employs the doppler shift principle, as does radar, and requires a reasonably accurate course and speed input. Well into the eighties it was all there was-and most ships did not carry it. It was not a "demand" system and one could go half a day without a fix, especially near the equator. Fixes in high latitudes were much more frequent due to the sats polar orbits.

GPS was started under the auspices of the Air Force and originally envisioned to have only 18 sats. The satellites are in geosychncronous orbit, at over 20,000 miles, and as such appear fixed in the sky.

My thoughts on the sextant wars have been amply aired elsewhere; I own one and am quite accomplished in it's use-20 years of use will do that for you. The Chinese missile was nowhere near capable of reaching GPS satellites. It is also unlikely for the US gov. to shut down the GPS system on an other than temporary basis. Anyone who relies on one solo system, of any type, for navigation has a fool for a navigator. If all electronic devices had to be shut down, as in a major world war, sea-going traffic would be about the last form of transportation affected. It's not like we're engaged in space travel and we actually need these little gizmos.

I continue to be amazed at the number of, otherwise intelligent, individuals who perceive a great and eminent military threat from the Chicoms. Afterall, we've got sixty year old ships laying in mothballs that are superior to what they have today. The Russian Navy, for all the hype, was crude compared to the US Navy. Our only serious technological concern with the Chinese is the fact they are a nuclear power. In the rest of the techno-wars we are way ahead and should remain so not withstanding the possiblity of some liberal pol declaring 'the end of war' and disbanding the DoD. It is instructive to recall all of the hype, in the Persian Gulf War, about Saddam's army, the fifth largest in the world, comprised of the finest Soviet tanks and technology. General Schwartzkopf and a modest force rolled through them in short order and probably could have been in Oslo in a couple of months if they so desired. If SDI funding continues apace I fully expect the US to be able to face any future Chinese threat. (barring something stupid; on the par of Clinton selling N. Korea nuclear power plants)


----------



## PBzeer (Nov 11, 2002)

Good post Sailaway, though I think one has to be cognizant of the difference in Chinese thinking versus Western. They have much less regard for their civilan population, and are not overly concerned about losing a billion or two of them. Much as with the jihadists, it's a totally different culture than most here can visulize.


----------



## sailaway21 (Sep 4, 2006)

No arguments there Beezer-that's the political end of things and neither the Chicoms nor the jihadists will beat us unless we first "surrender" in the political arena.

Militarily speaking, I'll take the US and/or Israelis and "give the points" to whomever wants the other side. Accepting bets now, escrow account required for wagering.


----------



## seabreeze_97 (Apr 30, 2006)

Astrolabio.................smirk.......blink, blink.............bigger smirk........Umm, that's not what it sounds like, is it?


----------



## sailaway21 (Sep 4, 2006)

Answer: actor in "Deep Inside Space", the 1974 XXX feature based on "The Jetson's". limited availability


----------



## PBzeer (Nov 11, 2002)

Yeah sail.....it's that political arena that worries me, not the military one. They did it once in Nam, now they're trying to again. (Which is the only real similarity between Iraq and Vietnam)


----------



## Idiens (Jan 9, 2007)

*Not really*



KeelHaulin said:


> In case you have not heard...
> http://www.americascup.com/en/americascup/teams/index.php?idIndex=&idContent=1876


Yup! but that is not serious yet, wait till they win!


----------



## Idiens (Jan 9, 2007)

Wind_Magic:- I think the biggest threats w/ GPS in sort of descending order are ...

Nice list, most of them also apply, with a little rewording, to the sextant. It can also be lost, stolen, not see the sky, have its almanac drowned, suffer human error in calculating and interpreting the fix. Chart datum issues apply etc.. So the message is: don't rely on any single devise. There's something in ColRegs that says a master must use all means available to avoid collision. So running aground by ignoring GPS and believing sextant is just as bad as the reverse.


----------



## sailingdog (Mar 19, 2006)

Idiens-

There's a difference between collision, which is hitting another vessel and grounding, which is hitting the land. You rarely use GPS to avoid collision. Mark I Eyeballs and Radar are far more useful for that... You do use GPS, Mark I Eyeballs and Radar or avoiding groundings. Sextants are rarely used to avoid groundings...as if you're in risk of grounding, generally you're in sight of shore and should be using coastal pilotage skills rather than celestial navigation. Celestial navigation is only for use when making long open water passages as a general rule, and not so useful once land is in sight.


----------



## Tartan34C (Nov 21, 2006)

sailingdog said:


> Sextants are rarely used to avoid groundings...as if you're in risk of grounding, generally you're in sight of shore and should be using coastal pilotage skills rather than celestial navigation. Celestial navigation is only for use when making long open water passages as a general rule, and not so useful once land is in sight.


I agree to a point and the use of sextants for piloting has falling out of favor but they are useful for rounding headland and dangers if two convenient objects on the shore are available and of course vertical angles of landmarks are sometimes useful for distance off. I have also taken a sight when going coastwise to see if I was north or south of my destination because a single LOP is fast to get and does intersect the shore at some point if the body is selected carefully.

Like almost any tool if you are familiar with it you can find a lot of ways to use that tool but like the antique tools we use to teach boatbuilding just being skilled with a tool doesn't mean it's the best choice for a given job.

The only down side I can see to increasing technology is that it reduces the overall skills needed and distances you from the history and traditions in sailing. This is OK if all you want are unskilled people sailing around with no regard to maintaining the traditions. Personally I would prefer a middle ground where people had some background in the old arts just so they didn't step on someone's toes when others wanted to sail in an old fastened way. Some people like biplanes and others like jets, both works just fine. I enjoy sailing with a minimum intrusion from technology and still use only a taffrail log, sextant and sometimes a hand lead to get from place to place and the places I am interested in are frequently on opposite sides of oceans.
All the best,
Robert Gainer


----------



## PBzeer (Nov 11, 2002)

Robert - in this era of increasingly "me first, instant gratification", consideration of others seems to be falling by the wayside. That's a skill we all need to practice.


----------



## sailingdog (Mar 19, 2006)

Well said Robert. I would agree that a sextant does have some very good uses for coastal pilotage, but it isn't a necessity for coastal pilotage. 

I generally plan landfalls so that I am clearly to a given side of my destination rather than have to check which way along the coast I need to go once I'm there. 

Consideration for others is definitely falling by the wayside with what John refers to as the "me-first" crowd. Unfortunately, today's technology, including GPS, high-speed internet, cellular phones, all make it far too easy to expect and want things right away. 

Technology does have its place, but so do traditional methods. In certain situations, each has its advantages... if you're boat has suffered an electrical problem, the sextant is probably going to be far more useful than the GPS... if it is heavily overcast, the GPS is going to be far easier to use than the sextant, and so on.


----------



## Giulietta (Nov 14, 2006)

One field where I see a reasonable comaparison between using sextants and "manual" navigating procedures, and using electronics is in schools today..

I remember when we had to learn how to do math "by hand and brain"...then calculators came along...you ask a college student now to do a square root calculation and he can't...too dependent on the calculator.

I believe that calculators are good, but people still need to know how toi do it manually..

Here, from the coastal skipper license upwards the "manual" navigation is obligatory in the school course...In fact, GPS and Chartplotter Navigation were not part of the program until 2 years ago...and still is not a subject that requires examination, as the other subjects do. They still require people that sail unrestricted coastal to know how to navigate with a sextant, and show they own one...
I don't know how it is in the US...

Just one question to Wind...are you sure you want to go to sea?? You don't seem conforatble at all..just my opinion


----------



## Idiens (Jan 9, 2007)

sailingdog said:


> Idiens-
> 
> There's a difference between collision, which is hitting another vessel and grounding, which is hitting the land. You rarely use GPS to avoid collision. Mark I Eyeballs and Radar are far more useful for that... You do use GPS, Mark I Eyeballs and Radar or avoiding groundings. Sextants are rarely used to avoid groundings...as if you're in risk of grounding, generally you're in sight of shore and should be using coastal pilotage skills rather than celestial navigation. Celestial navigation is only for use when making long open water passages as a general rule, and not so useful once land is in sight.


You miss my point, but never mind. Have you heard of AIS? That could be used for avoiding collisions and of course it does use GPS, (rather than a sextant). 
On your point: When you are not in sight of the shore, maybe due to poor visibility, and find yourself amongst the occasionally marked sand banks of the North Sea, say, radar does not help, no bouys for convenient warnings, eyes can't see them the bottom, the depth sounder provides a warning, but maybe too late... So a good chart and some cautious navigation are handy capabilities. GPS helps too.


----------



## sailingdog (Mar 19, 2006)

Idiens-

*GPS does nothing to help you avoid collisions... * I can't see how you are using GPS to avoid a collision... Boats don't show up on GPS... *I think you are confusing groundings, which is hitting shore, with collisions, which is hitting another boat.* _AIS is very useful for avoiding collisions, if your AIS will show up on your radar or chartplotter....which isn't the case with most of the ones out right now. _


----------



## Giulietta (Nov 14, 2006)

OHHHH My!!!! Jaysus, Mary, and Joseph, the Saints and Our Lady Of Fatima!!!!!!!! (All together at least 4 times)........

That's all I have to say at this point....


----------



## Idiens (Jan 9, 2007)

*Does AIS need GPS?*



sailingdog said:


> _AIS is very useful for avoiding collisions, if your AIS will show up on your radar or chartplotter....which isn't the case with most of the ones out right now. _


Odd, the IMO mandates AIS on SOLAS ships, one reason being to reduce risk of collisions. Granted they messed up the spec so that the minimum display is pretty useless. Snag is also that half the SOLAS ships don't carry ECDIS and their radars don't accept an AIS feed. However, all the kit I've seen for the less mandated of us either has a fairly adequate display of its own, or interfaces with both radar, chartplotter or PC.

For those interested in the effect, see www.aislive.com , there are more details on the European side of the Atlantic.


----------



## Giulietta (Nov 14, 2006)

Hey...that's me there!!!!!!!! Look its my house!!!!! yooooohooooo


----------



## Idiens (Jan 9, 2007)

Yes, I know the feeling. Even better, after some one kindly pointed us to marinas.com, I looked up Granton habour, which I only visited for a week last summer, and loh! J-L is in the picture.


----------



## Idiens (Jan 9, 2007)

Sorry, I don't visit often enough. J-L is the one on the very end of the pontoon away from the pier.


----------



## Giulietta (Nov 14, 2006)

Is it the blue cat??


----------



## Idiens (Jan 9, 2007)

No, its got a bit of green on it. A Coronet Elvstrom 38. A rare beast, not often seen outside the Baltic.


----------



## Giulietta (Nov 14, 2006)

Idiens said:


> No, its got a bit of green on it. A Coronet Elvstrom 38. A rare beast, not often seen outside the Baltic.


Can't tell from here, but I think there is one in the Algarve in Vilamoura, that belongs to a Dutch guy, or maybe a Belgium guy, as he spoke flameng.

Nice guy he was. That wasn't you was it??


----------



## Idiens (Jan 9, 2007)

Not me, but maybe J-L. I'm her forth slave.


----------



## Giulietta (Nov 14, 2006)

It was in 1996. I had an X then.....huuuuu fast.......


----------



## xort (Aug 4, 2006)

I rate my depth sounder as more important than my GPS.


----------



## Idiens (Jan 9, 2007)

It could be, J-L's lover then was a Dutchman.


----------



## wind_magic (Jun 6, 2006)

Giulietta said:


> Just one question to Wind...are you sure you want to go to sea?? You don't seem conforatble at all..just my opinion


Yes, I am comfortable. 

I like to talk about threats because I feel it helps me to mitigate risk.


----------



## Idiens (Jan 9, 2007)

Any votes for returning to the plumbline? I still carry one (a plumbline)-


----------



## sailingdog (Mar 19, 2006)

Idiens-

Are you talking about a lead line??? A lead line is a device used by sailors in past centuries to determine depth; a rope fixed with a lead weight was lowered overboard and then measured in fathoms (1 fathom=6 feet, or the distance of a man's armspan). Sometimes tar or wax was smeared on the end of the lead weight in order to obtain a sediment sample.

A plumb line is a reference line guided by a string or cord weighted at the end with a large weight known as a plumb bob. It is used to create a reference line to create vertical lines, where a spirit level may be impractical or difficult to use.


----------



## Giulietta (Nov 14, 2006)

We have a PLUMB line...our aunt Mathilda!!!   Will that qualify???


----------



## T34C (Sep 14, 2006)

G- Tell Auntie hello for me. She is obviously from your side of the family, same forehead. Perhaps she would make a better anchor than plumb line. However, if you dipped her bottom in tar I'm sure you could get a good sediment sample.


----------



## TSOJOURNER (Dec 16, 1999)

I knew from the start that this thread would get out of hand. T34C cracked me up on that last entry.


----------



## Idiens (Jan 9, 2007)

Sailingdog

I stand corrected. Always did confuse Latin with English. Or am I just swinging my plumb?


----------



## Giulietta (Nov 14, 2006)

I allways wonder....what went wrong with Columbus GPS.....did he use one of those chinese made ones????


----------



## sailingdog (Mar 19, 2006)

Nah, he probably had a Portugese navigator...


----------



## Giulietta (Nov 14, 2006)

SD, you may say a lot of good usefull things, but this post above is really bad....the Portuguese were the best navigators in the World, so if he ended up in the Caribbean, thinking he was in India, maybe he did not have a Portuguese navigator...or maybe he had, and the objective of columbus mission was to keep the Spanish away from the Portuguese routes to India...makes you think about it??? then check this out...

http://en.wikipedia.org/wiki/Salvador_Fernandes_Zarco

and find out how a Portuguese bastard cousin of King John of Portugal, named Salvador Zarco, born in CUBA, Portugal, jewish descendent, signed his name with a / means Zarco in hebrew, that was by coincidence the same signature that Columbus used...

This to say that now...this is coming out as the first big political conspiracy, made by Poprtugal to keep the Spanish away form going to India for commerce....


----------



## cockeyedbob (Dec 6, 2006)

WHO CARES! Get back to that incredible piece of Portugese deck fluff, Mathilda.


----------



## Giulietta (Nov 14, 2006)

cockeyedbob said:


> WHO CARES! Get back to that incredible piece of Portugese deck fluff, Mathilda.


Here ya go!!!!! Please be warned....after buying...our policy is NO RETURNS

Sorry T will you lend her to CEB??


----------



## PBzeer (Nov 11, 2002)

Actually Giu, that makes it easy to see which side of the family you take after. <G> And on the topic, you don't need a GPS cause all you do is go in circles. Probaly just have somebody on the bow pointing.....there's the next bouy!


----------



## cockeyedbob (Dec 6, 2006)

Yes sir, that's the one. Gonna screw in me squinky eye, the one with the red LED, and head on over to Port You Gal. The mate sez she doesn't look like an aunt, more like a mistress ... waddaya say?


----------



## pigslo (Nov 22, 2004)

She looks like Giu with hair by god!!
pigslo


----------



## Giulietta (Nov 14, 2006)

Pig, I resent that "Giu has no hair" thing...

By the way, Aunt Jamila, just found out that Aunt Mathilda is being so sucessfull in the US that she packed up and is moving to meet you after knowing you're so "popular" with women...

Here she is Pigs...enjoy Aunt Jamila!! She can cook a very good cus-cus!! 










She just nees a sink in the morning, so she can shave.....


----------



## cockeyedbob (Dec 6, 2006)

Sorry Pamlico, back to GPS.

Asked the mate, english major and professional student, what was the plural of GPS 'cause I have three GPSs, GPSes, GPSii or whatever?
Dumbfounded, she replied, GPS, satellite being either singular or plural, and then informed me I had none. What I have are GPS signal receivers and data processors, and why in heavens name did I need three of them to sail around the stock tank?

So, the most important piece of navigational equipment for me would be a sextant or perhape three sextants ... easier that way.

Redheads!


----------



## sailingdog (Mar 19, 2006)

Well, the photos of your aunts tends to explain your looks...


----------



## pigslo (Nov 22, 2004)

Too bad for Aunt Matilda that Aunt Jamalia got all the looks (or what was left). I would hate to be at your family reunion. Giu's aunt is so ugly that they used to tie a pork chop around her neck so the dog would play with her. 
pigslo


----------



## T34C (Sep 14, 2006)

Kinda makes you think they are coming from the shallow end of the gene pool.


----------



## TSOJOURNER (Dec 16, 1999)

I'm very concerned with all this anti-sino rhetoric. If this hysteria continues to accelerate, we may become very hard pressed to stock the shelves in Walmart! 
Regards,
Red


----------



## Giulietta (Nov 14, 2006)

pigslo said:


> Too bad for Aunt Matilda that Aunt Jamalia got all the looks (or what was left). I would hate to be at your family reunion. Giu's aunt is so ugly that they used to tie a pork chop around her neck so the dog would play with her.
> pigslo


Pigs,

And we used to do it....but the dog lost interest.....that's why she's commin' your way...she need a new husband....


----------



## PBzeer (Nov 11, 2002)

Guilietta said:


> ...she need a new husband...


That raises the question of where she found the first one.


----------



## sailingdog (Mar 19, 2006)

PBzeer said:


> That raises the question of where she found the first one.


Russian Mail Order Husbands right after the Iron Curtain fell.


----------



## Giulietta (Nov 14, 2006)

Nahhh...she was married to one of our dogs....but he developped some taste and left her....


----------



## HIPAR (Sep 8, 2006)

Lots of romantics here .. Give me a ship with sails and a star to navigate her by .. you know what I mean.

Just checked here:

http://earth-info.nima.mil/GandG/sathtml/satinfo.html

Yep, all the satellites are still there; All thirty of them. I'm receiving eight of them now from inside my living room! Need only three for a 2D on the water fix.

Takes about 24 of them for design goal performance. The system still works with less than 24 of them. Lots of launch rockets are required to shoot down the system. Use lasers or microwaves to burn them up? Not so easy.. they're hardened (like nobody ever thought about that)

Ever hear a call for assistance on your radio. What are your GPS coordinates?
No, I'm not too proud to use my GPS when I'm confused about where I am.

--- CHAS


----------



## Cruisingdad (Jul 21, 2006)

I AM SOOO MAD AT MYSELF. I missed all the fun on this thread.


----------



## camaraderie (May 22, 2002)

HiPar...welcome to the dark side where techno geeks carry 5 GPS's on board instead of buying one sextant for more money! They chant about acuracy while the luddites scream redundancy and pose doomsday scenarios for the failure of the GPS sytem. Little do the know that I have it in my power to push one button and......poof! <g>
Good to have a like minded spirit on board!


----------



## rtbates (Jan 30, 2007)

xort said:


> The Chinese Are Coming! The Chinese Are Coming!


They're already here. "MADE IN CHINA" is printed on lots of stuff on America's store shelves. It's as close as they want to get.

randy


----------



## wind_magic (Jun 6, 2006)

Was reading the log entries of the s/v FLYING PIG captained by Skip Gundlach (a contributor here) and it reminded me of this GPS thread here on Sailnet, so I thought I would stir the pot a little. Following is his recent entry into the log, a reflection on the recent grounding of the s/v FLYING PIG in the Keys of Florida.

http://groups.yahoo.com/group/TheFlyingPigLog/message/145



Skip Gundlach said:


> So, having discarded the Key West option, Lydia wanted me to get some sleep, as the boat was sailing along at a comfortable (for me) 5.6 under triple reef, again still far from anything. So, she took over and I went to the aft berth where the motion, while substantial, was easy and thus was of no issue, and I slept soundly. What I couldn't have known was that she was very uncomfortable, nearly seasick, and rather than standing watch, was on the saloon sole, popping up every few minutes, looking around, trying to make sense of the chartplotter which - since she'd not been monitoring it, and making range adjustments to look ahead and also in detail at where we were headed by zooming in along the intended route - she really couldn't comprehend, worsened by her physical state.
> 
> Looking back, she should have gotten me, despite how tired I was, or how much she wanted me to get some rest. My practice with the chartplotter would have revealed our course taking us dangerously close to the reefs on which we eventually came to grief, and we could have pinched up, rather than doing our broad reach, or, even, simply tacked off in the opposite direction, to take us away from where we were.


This all reminded me of the list of GPS threats I had written earlier in this thread. Always on the look out for opportunities to look brilliant even at the risk of seeming like a jackass I just had to dredge it back up. I've highlighted the things in the list below that I think were related to this incident. I think this incident perfectly highlights the kinds of "problems" with GPS that get people and their boats into serious trouble. This problem of zooming the chart in and not being able to judge the distance to hazards is I think one of the biggest problems with chart plotter use. That kind of thing doesn't happen with paper charts because the scale is always much more obvious because you simply can't zoom a paper chart unless you have a magnifying glass in your hand. Of course I'm not saying we should always use paper charts (an absurd thought), I'm just saying it is something to pay close attention to when using these gee whiz chart plotters.



wind_magic said:


> I think the biggest threats w/ GPS in sort of descending order are ...
> 
> Main threats ...
> 
> ...


----------



## Goodnewsboy (Nov 4, 2006)

A competent navigator is capable of using all available means to fix position. It is the use of two or more unrelated methods that often reveals an error derived from one or the other.


----------



## camaraderie (May 22, 2002)

Wind...you keep giving Chartplotter errors and calling them GPS errors. The GPS was not the problem. (Nor does it seem the chartplotter was wrong in this case.) What was wrong was the crew was either not capable of operating the chartplotter or was not plotting on paper charts from her GPS or simply was unable to navigate due to illness and made a grave error. (Or all three). 
It is a shame but Celestial wouldn't have helped her here...and even if she had piloting skills the keys are rather featureless and she was in no condition to figure anything out anyway. 
The real error here is an error of judgement and not one of navigational discrepancies. We all make errors of judgement...thankfully no lives were lost. 
We all hope Skip and Lydia come out of this OK.


----------



## wind_magic (Jun 6, 2006)

camaraderie said:


> Wind...you keep giving Chartplotter errors and calling them GPS errors.


Yes I was loose with the words GPS and chart plotter, and yet I imagined everyone would know I was speaking rather casually and not that I didn't know the difference. 



camaraderie said:


> The GPS was not the problem. (Nor does it seem the chartplotter was wrong in this case.) What was wrong was the crew was either not capable of operating the chartplotter or was not plotting on paper charts from her GPS or simply was unable to navigate due to illness and made a grave error. (Or all three).
> It is a shame but Celestial wouldn't have helped her here...and even if she had piloting skills the keys are rather featureless and she was in no condition to figure anything out anyway.
> The real error here is an error of judgement and not one of navigational discrepancies. We all make errors of judgement...thankfully no lives were lost.
> We all hope Skip and Lydia come out of this OK.


I didn't say celestial would have helped, I never even mentioned celestial. I simply said there are risks associated with relying on GPS/chart plotting and listed a bunch of common causes of failure, and then in this previous post said that I thought this incident fit a few of the things I had listed. I never said this incident had anything to do with GPS being inaccurate, that there were any kind of descrepancies, or anything of the sort. This isn't the first time this kind of thing has happened, people end up on the rocks all the time while using a chart plotter, for all kinds of reasons. I don't know why we can't talk about causes of failure while using GPS without everyone assuming you are saying GPS sucks, or that you shouldn't use it, or that you are suggesting people use celestial or whatever ... nobody said that. We should be able to talk about common problems with GPS/chart plotting in the same way we can talk about ways that a diesel engine can fail without everyone jumping to the conclusion that you are suggesting nobody ever rely on a diesel engine. I never suggested anyone not use GPS or chart plotting, I use it too, I have a bunch of receivers, hell I carry a GPS receiver with me everywhere and a compass, and I've written software to decode GPS strings too, I love GPS. But there is a lot of room for failure between a working system of GPS satellites and a total comprehension of context and full situational awareness, a lot of things can go wrong, I just listed some.


----------



## mega98 (Dec 11, 2006)

My instructor for coastal navigation said he couldn't pick up a GPS signal once while in thick fog. Anyone else had this problem?


----------



## sailingdog (Mar 19, 2006)

A problem I've seen is that some people mistake the icon on the chartplotter screen for their position in the real world... it isn't. It is an electronic representation of a location of a physical boat on a probably inaccurate rendition or interpretation of the real world by a cartographer, often using data that is decades old. In many cases, it is good enough to prevent disaster, but there are places where the cartography and the real world don't even come close. 

Mega98-

I've seen few situations where the GPS couldn't keep signal lock in torrential rain, and believe that the GPS signal, which uses just a 50 Watt transmitter IIRC, can be attenuated by water as is the case with most other radio signals. However, I get the feeling that fog would have to be exceptionally dense and high-reaching to attenuate the signal that much. 

Of course, there are other factors involved... was his GPS being used inside the cabin with an integrated antenna? Was it a parallel channel, multiplexed receiver or a single channel receiver? Was it a shipboard unit with an external antenna? Were his batteries fresh? Etc...


----------



## btrayfors (Aug 25, 2006)

mega98,

GPS signals are subject to error from a number of sources, including water vapor, though the error is usually small. However, there's an interesting tale on the DARPA website of a GPS signal apparently being significantly in error due to reflection of the signal off a landmass. 

Here's part of that discussion: "Posted - 17 August 2004 14:15 DaveB - I've seen that satellite alignment problem in real life. My little handheld GPS was telling me that the EPE was 900 ft and the navigation display was pointing in a direction I didn't want to go. There were two satellites on the horizon and four directly overhead in a nice straight line. I found another problem last fall. I was approaching an island in my sailboat in heavy fog and suddenly the GPS was telling me to turn hard to the right. About the same time a cliff loomed out of the fog directly in front of me. I recognized the piece of the cliff I could see and groped my way in from there but the GPS would have lead me on to the beach. I don't know what kind of GPS interference you get off a cliff but I wish DARPA would rely less on GPS and concentrate on the harder problem of intelligent navigation. Rich"

Just goes to underscore the most fundamental rule of navigation: use all available means to fix your position, and don't rely 100% on any one source.

Bill


----------



## camaraderie (May 22, 2002)

Wind...sorry if my verbage wasn't specific enough about what I was complaining about. A large part og this thread has been about GPS and the need for Sextants and Coastal Piloting skills as backup. More recently we have those in favor of keeping Loran as well as a redundant backup on another thread. 
My attitude remains that (in addition to keeping accurate paper charts and plotting as you go) GPS is all you need these days as long as you have multiple GPS's running and plenty of cheap backups w/ batteries. 
This comes in for some criticism by others (damn luddites! <g>) but your posts which LUMP GPS and Chartplotters together (even though I know you know the difference) make it seem like there is DANGER in relying on nothing but GPS and your own eyes. The reality in my opinion is that there is danger in relying on anything ELSE other than GPS and your own eyes (which includes keeping a paper track and comparing reading from 2 GPS's to eliminate error possibility to the vanishing point.) *I agree with you about chartplotters.*..my comments on Celestial were for others on this thread. So if you say chartplotters or CP's instead of using GPS interchageably in you posts...we can talk about them without a problem all you want.


----------



## Pamlicotraveler (Aug 13, 2006)

The problem with Scott and Lydia's grounding seems to have been more fatigue and seasickness than any type of technology failure. And if you feel like you are going to lose your lunch I doubt a sextant would help that problem much. I think the lesson of their story is to keep planning and keeping abreast of your bearings when things seem to be going well. That way you can make decisions without too much required concentration when things aren't going well.

The same concept for me is to pencil in my GPS location on a paper chart at reguLr intervals, even though I have a chartplotter, and if I get sick (or the Chinese shoot down our GPS system  ) I will have course to follow without having to do alot of thinking.


----------

