Nobody really needs to know how to navigate anymore, do they?

[Mike OReilly]

Fun old thread. I appear to experiencing a bit of cognitive dissonance with this one. While I think want paper charts, the fact is, I've been cruising in a relatively challenging area (Newfoundland) for a few seasons now with ZERO paper charts.

I keep meaning to pick some up, and have half-heartedly tried a couple of times, but I continue to rely on pure-digital. So far, have not had a problem. And yes, I carry multiple GPS units with four (soon to be five) independent chart sets.

I still think paper is a good idea, and I'll get around to picking some up ... eventually .

[Adelie]

Originally Posted by donradcliffe

If the gps system is turned off, it will be the least of your problems. My son tells me the world money transfer system is tied to gps time.

If I am in the middle of the ocean, when the GPS system goes down, I will be much more concerned about getting to shore without hitting anything hard than whether or not my ATM card works.

[newhaul]

Originally Posted by Mike OReilly

Fun old thread. I appear to experiencing a bit of cognitive dissonance with this one. While I think want paper charts, the fact is, I've been cruising in a relatively challenging area (Newfoundland) for a few seasons now with ZERO paper charts.

I keep meaning to pick some up, and have half-heartedly tried a couple of times, but I continue to rely on pure-digital. So far, have not had a problem. And yes, I carry multiple GPS units with four (soon to be five) independent chart sets.

I still think paper is a good idea, and I'll get around to picking some up ... eventually .

I bet you have one of those new fangled composting heads to.

[Jammer]

There are three things that can go wrong that require navigation skills to fix:

1) Loss of chartplotting capability
2) Loss of onboard GNSS capability
3) Loss of GNSS signals, whether locally or worldwide.

I think it is important to recognize that getting an accurate lat/long from a GNSS is not sufficient to provide navigation without applying different skills than using a chartplotter or an app on the phone. These systems are more fragile and have less redundancy than onboard GNSS capability -- they require more power, much more in the case of dedicated chartplotters, and they require data, applications, have to be unlocked, etc. It takes charts and skill to navigate any meaningful distance, safely, using only electronics that provide lat and long.

I had a Garmin Montana for a while. Waterproof, good battery life, can run on AA batteries, can be loaded with marine charts. It's at the bottom of a river now (long story) but it was expensive for what it was ($1000 including charts and battery tray) and required a certain amount of practice and ongoing maintenance. I don't plan to replace it.

I don't think wrapping an old phone in tinfoil and putting it in a drawer provides a meaningful level of redundancy.

Local/regional disruptions of GNSS due to jamming or interference are common and don't necessarily require a war. All GNSS systems operate in a fairly small set of channels around 1100 MHz and 1700 MHz and can be jammed using well-known techniques. A couple years ago some guy put a GPS jammer in his pickup truck so his boss couldn't track him and ended up disrupting aviation uses in the vicinity of a major airport. All major militaries have GNSS jamming capabilities and many use them routinely around certain assets.

Re constellations, I checked several chartplotters on the market today, none support Beidou, one supported Galileo, two others apparently support GPS only but can use GLONASS as a means of improving accuracy but apparently not as the only means of position determination (though this was unclear from the literature). Older chartplotters are less likely to have support for anything but GPS.

Most chartplotters are not usable for navigation without GNSS data. You cannot, for example, set up a track, and input the lat and long and see how far off your track you are or how long it will be until you reach the next waypoint.

I think the constellations are more vulnerable than is generally believed although obviously they enjoy powerful state sponsorship.


I always carry a few paper charts that are sufficient to complete a voyage.

[Jdege]

Originally Posted by donradcliffe

If the gps system is turned off, it will be the least of your problems. My son tells me the world money transfer system is tied to gps time.

My guess is that they're using the Network Time Protocol, which relies on multiple servers, some of which are syncing to the GPS satellite signals, which are synced to a number of atomic clocks. Other NTP servers sync to the atomic clocks directly. Most NTP servers sync to multiple other NTP servers.

It's all designed with typical Internet redundancy. If GPS goes out, the system will still work. Even if all of the atomic clocks go offline, the system will still work, though it will drift slowly, then resync when they come back up.

Even if the Internet shatters, breaking into multiple fragments, each fragment will maintain time, and will resync when communication is restored.

[El Pinguino]

You can have as many GPS units as you like. But Lat/long is of limited use unless you know the Lat/long of the land and stuff. So how many chart plotters do you carry to provide redundancy? I carry 4, fixed PC driven display, Macbook, iphone, ipad but I can imagine events where all four could be toast. Unlikely events but events nevertheless.

[Anders]

Originally Posted by Bulawayo

I’ll not forget people that were caught out during the first Gulf War when USA turned off the GPS. That is always a possibility and could recur.

USA did not turn off the GPS during the first gulf war. They did turn off selective availability so that everyone could get the same precision as the military GPS units.

[Anders]

Originally Posted by donradcliffe

If the gps system is turned off, it will be the least of your problems. My son tells me the world money transfer system is tied to gps time.

I don't know anything about money transfers but lots of datacommunication equipment has a GPS antenna to provide an accurate time.

[Mike OReilly]

Originally Posted by newhaul

I bet you have one of those new fangled composting heads to.

And a portabote, and a manual windlass, and a windvane … clearly, I’m not to be trusted [emoji6].

[Bulawayo]

You are plainly having an axe to grind. I suspect it is because the use of traditional navigation is beyond your knowledge. The US most certainly switched out the GPS for a couple of days and then turned off the selective capability for a couple more days at the commencement of the Gulf War. Try Googling it. For some, Ignorance is bliss.
Trying to introduce new arguments? Hmmm - doesn’t work with me. If the US turns off the GPS system, it’s virtually assured that so will all other system operators. That should be blindingly obvious. . Similarly, that risk is increasing with growing tensions in Eastern Europe as well as further East. Notwithstanding, an electrical event on board can also subjugate electric/ electronic devices. This includes a lightning strike or any other electrical catastrophe. You clearly have not understood the points I have repeatedly made and instead attempted to impose a different scenario to try and justify not appreciating the issues. I’m not lowering my intellectual standards any further by communicating with someone that argues pointlessly in an attempt to justify a non- appreciation of the subject and clearly has limited experience off-shore. .

[Jammer]

Originally Posted by Jdege

My guess is that they're using the Network Time Protocol, which relies on multiple servers, some of which are syncing to the GPS satellite signals, which are synced to a number of atomic clocks. Other NTP servers sync to the atomic clocks directly. Most NTP servers sync to multiple other NTP servers.

It's all designed with typical Internet redundancy. If GPS goes out, the system will still work. Even if all of the atomic clocks go offline, the system will still work, though it will drift slowly, then resync when they come back up.

Even if the Internet shatters, breaking into multiple fragments, each fragment will maintain time, and will resync when communication is restored.

There are a number of important systems that require more accurate time synchronization than NTP can provide. Cellular phone systems are one example.


I used to have a TXCO based time source in my lab that incorporated a GPS receiver, and it was far better than NTP. If left unconnected to an antenna, though, it would start to drift after a few days. I think there's greater use of rubidium standards in telecom and other synchronicity dependent industries now that those have come down in price and with greater awareness of GPS's vulnerabilities, but they drift enough to pose a problem for some applications within a matter of days or weeks.

[sepharad]

Given that the Admiralty is discontinuing paper charts in what...4 years? It is slowly being decided for us. I WANT a paper chart. Most people no longer do. Maybe someone else will pick up the slack. I think a back up is always smart. a flotation vest, EPIRB, Radio, Raft, Flares. A chart is another backup at worst. We get to make a personal choice.

[Jammer]

Originally Posted by Mike OReilly

And a portabote, and a manual windlass, and a windvane … clearly, I’m not to be trusted [emoji6].

Careful, you might become a Bull Rail Apologist if you keep this up.

[wholybee]

Last year I ditched all my paper charts. I wasn't using them, and I ran out of space. No reason to keep something you don't and won't need, that is taking space you do need. I *do* have a sextant on board, and a tablet of plotting sheets, and a basic knowledge of celestial navigation. Enough at least to get me to sight of land should everything else be lost. But I don't expect that will ever happen-it was mostly for my own satisfaction to learn it.

It is _possible_ that GNSS will fail/become unavailable or whatever. But the likelihood is (IMHO) approaching zero. With multiple redundant GNSS systems, redundant receivers on my boat, some of those battery operated and protected from lightning etc.

With that said, we have new tools, GPS, chart plotters, etc., but that just means the techniques for navigation are changed, it doesn't mean we no longer navigate. We still watch depths, currents, tides, plot courses to avoid other vessels based on CPA given by our chart plotters, calculate fuel requirements, estimate time of arrivals etc. I draw lines all over the charts in OpenCPN just like I did with paper charts to estimate when and where I will need to tack, mark off safety areas/lines I don't want to cross, etc. just like I did with paper charts. All of those are still skills to be learned, and a competent sailor will learn them, and not just use a GPS and point the boat in some given direction.

Pilotage, I think, is still much the same. While my chartplotter does give me a location and saves me from working a fix, I still compare the chart to my surroundings, identify all the buoys, lights, and other distinguishing features on the chart, and orient myself in space so that I am steering based on what I see, not staring at the chart. A GPS does not replace the necessity of that, although new boaters with less experience might just steer by the chartplotter, it isn't safe.

[Jdege]

Originally Posted by El Pinguino

You can have as many GPS units as you like. But Lat/long is of limited use unless you know the Lat/long of the land and stuff.

Do you know how to convert from the datum of your GPS to the datum of your chart?

Because LatLon in one datum is not the same as LatLon in another.