GPS anxiety

[AntarcticPilot]

I err to the age old system ...

If I have to dead reckon ... then I purposely run upwind of destination to be sure I can then coast hug down to it ...

I have paper charts ... I also have PC based that can auto DR / EP to give me an idea of where I may be ...

I always aim to know which way to safe water. Same strategy as "We Didn't Mean To Go To Sea"! But I dislike being in confined waters where no direction is safe for long.

 

[Refueler]

Surely any sailor has in mind where he is where is going and how fast he is going. Yes GPS gives precision and yes it would be difficult without GPS but surely not a reason to worry unnecessarily. Much more to worry about when sailing than GPS failure. ol'will

As an ex Ships Officer - working in pre Sat nav and then in Sat nav eras ... plus own boats etc. - the amount of error in DR and 'calculated' EP can be huge at times ....
Yes we have Ocean / Current Charts to use to 'guesstimate' drift / leeway / effects - but conditions 'on the day' can be vastly different ...

20,000 ton ship West Africa heading west .... we should have been over 50nm off coast ... but no sights / no position for serious period .... on watch and saw Gas Flares ... switched on Ech-sounder ... we were skirting edge of oil fields far closer inshore than EP said ...

70,000 ton ship Indonesia to Arabian Gulf ..... no sights for days due bad weather .... ended up over 200nm south of EP said ..

S**t happens.

 

[blush2]

In the days of Decca they always seemed to turn off the beacon chain in the Channel Islands over the May bank holiday

Seriously, I would be more concerned about a power failure on board. Apart from no plotters, no GPS etc, if you don't have a traditional compass you could have a problem.

 

[Refueler]

In the days of Decca they always seemed to turn off the beacon chain in the Channel Islands over the May bank holiday

Seriously, I would be more concerned about a power failure on board. Apart from no plotters, no GPS etc, if you don't have a traditional compass you could have a problem.

What was that old Scouts trick with the wristwatch ?? Hour hand >>>> etc ?

 

[B27]

I could do 98% of my sailing without GPS and it wouldn't worry me at all.

I have been caught out in fog a few times, had GPS chosen those points to go AWOL, it would have been annoyance and hassle.
This includes on other people's boats with radar, I've been concerned that radar images can be interpreted to show you what you expect to see!

I've played the RYA blind nav games, done DR and all that, but would not choose to rely on such stuff in a crisis.

 

[RupertW]

In the days of Decca they always seemed to turn off the beacon chain in the Channel Islands over the May bank holiday

Seriously, I would be more concerned about a power failure on board. Apart from no plotters, no GPS etc, if you don't have a traditional compass you could have a problem.

A power failure wouldnt be a big deal for us with the inability to start the engine being the worst part, as well as lights for visibility, but we have battery lights thst would last a few hours and B&Q solar lights that last almost til dawn. Hard to see how all that might happen and not be jump-lead fixable without major flooding.

Navigation-wise we navigate on tablets so essentially have two ipads and two phones with GPS and Navionics, so could probably manage 48-72 hours with full normal nav by powering then on one at a time. Enormously longer if we just powered them on once every 24 hours in an ocean crossing.

 

[14K478]

Every half hour is a bit keen. Every hour or two.

 

[Baggywrinkle]

What was that old Scouts trick with the wristwatch ?? Hour hand >>>> etc ?

How to Use an Analog Watch as a Compass: 8 Steps (with Pictures)

 

[billyfish]

What's a watch ? I think what Tom Cunliffe has developed is a great idea , angel something, Might stop me buying paper charts.

 

[Baggywrinkle]

What's a watch ? I think what Tom Cunliffe has developed is a great idea , angel something, Might stop me buying paper charts.

AngelNav

 

[john_morris_uk]

I don’t lose any sleep worrying about GPS outages (whether external loss/jamming or internal power failure/lightening strike etc)

We do carry paper charts, compass, log (plus mechanical backup log), sextant, tables, nautical almanac and plotting sheets.

No paranoia, just good seamanship IMHO.

 

[Chiara’s slave]

Ha Ha Ha ... AIS ???? That uses GPS to sort position of WHERE that AIS target is ... so you can fiddler as much as you like with plotter / screen - but AIS is no use to you if GPS is 'out' ....

But don't forget that US GPS is not only system and many sat gear today can pick up more than just US sats ...

Does AIS just use GPS? My plotter is trilingual, I believe. To think that all 3 would go down at once is beyond thinking about. But, there's always a paper chart, and old fashioned chart gear on board. I’d worry far more about electrical failure than GPS failure.

 

[Refueler]

I could do 98% of my sailing without GPS and it wouldn't worry me at all.

I have been caught out in fog a few times, had GPS chosen those points to go AWOL, it would have been annoyance and hassle.
This includes on other people's boats with radar, I've been concerned that radar images can be interpreted to show you what you expect to see!

I've played the RYA blind nav games, done DR and all that, but would not choose to rely on such stuff in a crisis.

300,000 ton ship bound for OFfshore Louisiana Terminal ..... I took over watch and checked position ... previous OOW had been using radar pos'ns from Jamaica coastline displayed .... he was two ... yes 2 headlands out !! Lucky that dist off was enough to keep us safe ...

Its easily mistaken ....

 

[Refueler]

I could do 98% of my sailing without GPS and it wouldn't worry me at all.

I have been caught out in fog a few times, had GPS chosen those points to go AWOL, it would have been annoyance and hassle.
This includes on other people's boats with radar, I've been concerned that radar images can be interpreted to show you what you expect to see!

I've played the RYA blind nav games, done DR and all that, but would not choose to rely on such stuff in a crisis.

If you want harrowing .....

I was working for a Shipping Co that had vessels sailing blacked out and silent carrying Crude from (Iran) Kharg Island down to Siri and Lavan Islands .. we basically slept on deck away from 'heat sources'. Accommodation was directly over engine rooms and missiles from Iraqi used to hit there ... aided by our cousins across the water of course who had a Command Control Frigate (Perry I think) stationed right in middle of the Gulf.
Nav Aids were ?????? Radar was ???? We tried in convoys ... odd ships got hit ....

My Wife at that time (UK) suggested life was better than the money for sailing such .... so I accepted Company's offer to transfer to non combat zone ..

Ha Ha ... transferred to Miami and then found we were Gun Running for CIA to Central America ... YES - that scandal !

I hated that ship ... and then I was offered place with an American Oil Co's ships - manned out of Copenhagen ... FoC of course ...

Off I go ... happy to be back on tankers .... guess what ...

Hey Nigel - you were on Gulf Shuttle before ??

Yes I was ..

We have you assigned to MT xxxxxxx - you join offshore Mississippi ....

I find myself back in Gulf - now running Crude Shuttle for Iraqi's ... with Iranians now targeting us ....

You can't make this s**t up ... its just one of those things ...

Oh forgot to mention - the one trip we made from Miami to Port au Prince Haiti .... when Papa Doc jr was being thrown out and full scale riots going on !!

I'll leave out stuck in Crimea for 4.5 months when it changed to Russian ... looking after Libyan Oil supplied to Nato once fighting reduced ...

 

[Refueler]

Does AIS just use GPS? My plotter is trilingual, I believe. To think that all 3 would go down at once is beyond thinking about. But, there's always a paper chart, and old fashioned chart gear on board. I’d worry far more about electrical failure than GPS failure.

Its not only the AIS transmitting -= but also your reception ... if either only uses US GPS - then say goodbye to AIS targets on your screen.

But if both have multi input .. ie Galileo (UGH!) .. Beidou (actually good) ... Glonass (better than some realise) (I forget name for the Indian system) etc. then fine .. except >

EU agreed with USA that Galileo would be allied to US GPS - such that it would be switched off if US deemed conflict and they were switching of US GPS (commercial) ... Military have own channel.

 

[Chiara’s slave]

Thats what I thought. I can remember SA being used in the first Gulf war, accuracy down to a mile or so IIRC. So far it has never been switched off. The chances of electrical failure on board are far higher. That is what we should be worrying about. Back to the 1930s in one swift moment.

 

[RupertW]

Thats what I thought. I can remember SA being used in the first Gulf war, accuracy down to a mile or so IIRC. So far it has never been switched off. The chances of electrical failure on board are far higher. That is what we should be worrying about. Back to the 1930s in one swift moment.

As per my earlier post on this, why? What sort of electrical failure might have an immediate effect on navigation? If it’s within a day of land then individual batteries will work fine and if it’s weeks away then you only need to switch things on to check for a few minutes every couple of days. And that’s lots of time to fix the power problem.

 

[Chiara’s slave]

As per my earlier post on this, why? What sort of electrical failure might have an immediate effect on navigation? If it’s within a day of land then individual batteries will work fine and if it’s weeks away then you only need to switch things on to check for a few minutes every couple of days. And that’s lots of time to fix the power problem.

A short? Something chafing though a wire? 24 hours and every battery on my boat would be flat, except that, unlike most of you, I can hand start my engine, and have supplies and spares to enable me to run stuff as long as I have fuel. And I’d run out of water before that happened. It requires a change of strategy, that’s all. What would you do?

 

[RupertW]

A short? Something chafing though a wire? 24 hours and every battery on my boat would be flat, except that, unlike most of you, I can hand start my engine, and have supplies and spares to enable me to run stuff as long as I have fuel. And I’d run out of water before that happened. It requires a change of strategy, that’s all. What would you do?

I get that lots of things could cause domestic batts to fail but if we assumed total electrical failure that somehow couldn't be sorted at sea then it wouldn’t cause any navigational problems as we have Navionics as well as normal GPS position on our two phones and iPads, so would start being strict about one on at a time and no more movie watching. That would give us maybe 72 hours of continuous chartplotter lite, plus of line of sight snd DR if needed.

If it was an ocean crossing then even easier - switch one of the 4 devices on for 5 minutes each day or even every few days and we’d probably get across the pacific before all 4 ran out.

I would hope that there would be plenty of ways of fixing the original problem, though, in that time.

 

[Chiara’s slave]

I get that lots of things could cause domestic batts to fail but if we assumed total electrical failure that somehow couldn't be sorted at sea then it wouldn’t cause any navigational problems as we have Navionics as well as normal GPS position on our two phones and iPads, so would start being strict about one on at a time and no more movie watching. That would give us maybe 72 hours of continuous chartplotter lite, plus of line of sight snd DR if needed.

If it was an ocean crossing then even easier - switch one of the 4 devices on for 5 minutes each day or even every few days and we’d probably get across the pacific before all 4 ran out.

I would hope that there would be plenty of ways of fixing the original problem, though, in that time.

And the chances of TPTB switching off GPS for longer than a few hours are vanishingly small too. Everyone knows how dependent many aspects of modern life are on sat nav. So really, my paper charts, bearing compass, Breton plotter and dividers are just dead weight.