Challenge: GPS Stops Working !

[Pagan]

Originally Posted by boatman61

LOL..... no engine... just 6 of us rowing..

Rowing up and down the Tamar in January 1964, freezing, yet fun. Loved the Montague as well of course. Still loved it then and love it now.

ARE WE MAD?

[obama6493]

Originally Posted by jcapo

Two sextants and chronometer on board from before the days of GPS. I
haven't worked a sight reduction by hand in years and I doubt I could do
it in a reasonable amount of time if I had to. So I opted for the Starpilot
software running on a high end TI calculator for sight reduction. Backup
for that would be by hand on paper.

John

You can get a cheap plastic sextant for less than $ 100. Then you must learn some-
-things. If using one saved your skin ?? Well now, just remember to take many shots at a time and carry an accurate watch. Shoot the sun at 12:00 noon when sun is highest and there's one fix. Then take many for lats.

[boatman61]

LOL..... these debates crack me up sometimes...
if the GPS dies you should have enough education from your geography classes to get you safely to land... its not like 150yrs ago... we know a hell of a lot more of the world now than then.. including ocean currents...
just knowing your last position should be enough to see you safely to a port....
the problem with the modern techs is that the only thought that enters many a persons head when all the toys fail is "PANIC"......
Don't panic... its a piece of cake... if I can do it(and have)anyone can....

[Captain Bill]

Originally Posted by boatman61

LOL..... these debates crack me up sometimes...
if the GPS dies you should have enough education from your geography classes to get you safely to land... its not like 150yrs ago... we know a hell of a lot more of the world now than then.. including ocean currents...
just knowing your last position should be enough to see you safely to a port....
the problem with the modern techs is that the only thought that enters many a persons head when all the toys fail is "PANIC"......
Don't panic... its a piece of cake... if I can do it(and have)anyone can....

I completely agree with you, this is very funny. The problem is you are assuming that just because "we" know more about the world than we did a 150 years ago that modern technology dependent skippers actually know anything. I've seen plenty of evidence that they don't know anything including their current position. Since they have never done anything without their technology they easily panic if it fails. Unfortunately these people can get somewhere and have their tecnology fail and be totally screwed.

[bvimatelot]

Originally Posted by Captain Bill

I completely agree with you, this is very funny. The problem is you are assuming that just because "we" know more about the world than we did a 150 years ago that modern technology dependent skippers actually know anything. I've seen plenty of evidence that they don't know anything including their current position. Since they have never done anything without their technology they easily panic if it fails. Unfortunately these people can get somewhere and have their tecnology fail and be totally screwed.

Agreed. (I sometimes also wonder about small aeroplane pilots as well - I dont think they are even taught the basics nowadays?) On my last submarine my captain would turn off SINS for days on end and we had to DR and EP on using depth contoursl together with an expanding pool of errors.

Much of the "thrill and excitement" or sense of achievement of making a land-fall has been lost with the advent of GPS and there are too many "sailors" who shouldnt be where they actually are but gps has allowed them to get there! T

[lannen]

I purchased an EPIRB in case my autopilot or chartplotter dies.

[David M]

There is not any debate on how to do this because it has been done since the 1800's by naval and merchant ships long before GPS, electronics or yachties.

You do it by running a DR and taking celestial sites. You keep time with three chronometers knowing the error and the rate of that error. You wind these clocks once a day at the same time GMT. You can do your sight reductions the hard way with spherical trig or the easy way with sight reduction tables.

Knowing your DR error between fixes you can start making more accurate DR's.

There is absolutely no electronics needed to get within 3 miles, twice a day, weather provided.

That is how it used to be done.

[Charlie]

Given my skills I would do this. I always carry paper charts. I also write down the lat and long on an hourly basis from the GPS along with the course and heading. Given that the angle between the horizon and the North Star is the same as your latitude. I would figure out the latitude I want by the chart and then follow my compass course using DR to approximate my longitude. I would like to learn celestial Navigation though

[Zednotzee]

Originally Posted by boatman61

the problem with the modern techs is that the only thought that enters many a persons head when all the toys fail is "PANIC"......

I wouldn't panic if my chartplotter/GPS failed. Now, if the depth sounder failed, that's another story!

Originally Posted by lannen

I purchased an EPIRB in case my autopilot or chartplotter dies.

LOL! But, what if it's a satellite/solar flare problem? What's your EPIRB backup?

[lannen]

Originally Posted by Zednotzee

LOL! But, what if it's a satellite/solar flare problem? What's your EPIRB backup?

Homing parrot~

[barnakiel]

Probably just keep on going by the compass and aim for a tall island and far away from any reefs. No big issue.

If there is no such tall island, then just take out the sextant, take some sights and get your fix and that's it.

I think Atlantic is easy but Pacific could be tricky in some locations - all downwind landfalls could be low lying and extremely coral-infested.

b.

[skipmac]

Perhaps I'm just nitpicking but to me the very title of this thread bothers me.

In my opinion, anyone crossing an ocean (or crossing a bay for that matter) that would consider it a "challenge" if the GPS quit has gotten in over his or her head.

[capn_billl]

Originally Posted by Charlie

Given my skills I would do this. I always carry paper charts. I also write down the lat and long on an hourly basis from the GPS along with the course and heading. Given that the angle between the horizon and the North Star is the same as your latitude. I would figure out the latitude I want by the chart and then follow my compass course using DR to approximate my longitude. I would like to learn celestial Navigation though

I like this. Since the entire goal of celestial navigation is to find out approximately where you are, why not make it simple?? North star or equivalent for lat, then waterproof digital watch with the sun, or rise time of a common constellation for long. Remember all I have to do is get with VHF range of a coast. I would like to learn how to use sight reduction table, (spherical trig gives me a headache).

My main goals are in any cercumstance I may find myself adrift at sea, How with the materials I'm likely to have at hand, A. find out where I am ? B. Find nearest landmass? C. Get there.

In the above example of losing nav equipment on the way to Bermuda, I would have probably turned around and aimed for the USA, I don't think I would miss the entire North American continent. Finding an island in the middle of the Atlantic is pretty darned good shooting.

[barnakiel]

Originally Posted by capn_billl

In the above example of losing nav equipment on the way to Bermuda, I would have probably turned around and aimed for the USA, I don't think I would miss the entire North American continent. Finding an island in the middle of the Atlantic is pretty darned good shooting.

You could also do the following:

- continue by DR to the place where the island 'should be', then sail N-S the distance you think you might have erred, if the island is still not there, go back to the continent.

Not applicable with every island but can be done if the island is high enough and not surrounded by some sort of horrrrrible reefs.

b.

[barnakiel]

Taking down coordinates (from the GPS):

Our way: every time I mark the chart I put the coordinates at the point. Now between the points (on a passage I only mark the chart once a day) I will mark a WPT everytime I turn on the GPS (which can be dozens, few, or nill times a day). Should the satellites or the receiver refuse to co-op, I still have my WPTs (unless the unit pack up).

Yes, I know it is a compromise. But a safe one - as we approach the landfall or any 'obstacle' I will mark the chart / note courses / drift / etc.. accordingly.

b.