Navigation Style for Day Skipper - Advice from Instructors?

[alant]

I agree, I remember the same old **** being spouted when pocket calculators became available. My mum had similar views when the type writer was being replaced with word processors and my architect friend stating you will never replace a drawing board with a PC....
The whole single point of failure thing is just stupid, what happens if the ludite navigator falls overboard - oh wait I know we will have two, oh and incase the boat sinks we can get another one to follow us....

Do you have all those on board as well?
Its a wonder you can see the horizon, if you keep looking at all those things.

 

[Babylon]

I agree, I remember the same old **** being spouted when pocket calculators became available. My mum had similar views when the type writer was being replaced with word processors and my architect friend stating you will never replace a drawing board with a PC....
The whole single point of failure thing is just stupid...

Architects and designers don't design buildings and things on either a drawing-board or on a computer - they first explore the design by way of freehand concept sketches. Then - once they've understood the idea they're dealing with, they'll use the convenience of the drawing-board or CAD programme to resolve the design to scale and detail. CAD is very useful in then dealing with change, or adding complexity, etc - but any creative person worth their salt is a draughtsman first and foremost and a computer-operator afterwards.

As to 'single-point of failure', it's not "just stupid" as you suggest. By way of example: a colleague of mine in his 40s was driving me from Cirencester to Wantage via Swindon. I know the route well, so I suggested he switch off the (irritating) SatNav on his mobile phone. Notwithstanding the occasional direction I gave him (eg "go straight over the next roundabout" or "follow the signs to Swindon") he became totally flummoxed. He also fessed up to the fact that his smart-phone battery was low and that the 12v charger didn't work, but that he no longer bothered to keep an atlas in the car!! Now that is not only stupid, it also demonstrates the speed with which the average Joe loses skills he no longer has to practice.

Beyond all that, for me and I'm sure many others on here, a great deal of the joy of sailing is in navigating a passage well and piloting my way into/out of harbour using traditional methods. I prefer to do it manually, even though I have both a ship's GPS and a handheld plotter. I'd hate to become as 'stupid' as the checkout kid at Tesco's who doesn't know how to double £1.99 on paper let alone in their heads.

 

[Mark-1]

also demonstrates the speed with which the average Joe loses skills he no longer has to practice.

Nobody is going to forget how to calculate two simple vectors where the inputs required are self evident there's plenty of thinking time because the vessel is travelling at a fast walking pace. And I'm speaking as someone who is helpless without in car sat nav.

 

[roblpm]

Yes, but they didnt really mention sailing straight in to the wind!!

 

[Deleted member 36384]

To be honest, I've never drawn a circle of error or seen one drawn but I bet whatever values are chosen they are more than 5m .

They can easily be 5 - 10 km after 60 miles. However, by using stuff like the scent of bark, or type of bird one can .......... okay, I am not serious, but using information such as soundings and single bearings one can reduce the error as appropriate. However, that is not the point. Being comfortable with all the principles (process as AntarcticPilot says) of coastal navigation or Plane Sailing Navigation allows one to use electronic aids without 5 back ups. There is a further point to be made here - one doesn't really need the precision and certainty that modern aids to navigation give, it leads can and has lead to a false sense of security or insecurity. Having said that, I will always have a plotter on a boat now and I always take my small GPS with me; it's just so convenient.

 

[RupertW]

I still prefer to sail without a chartplotter, but have had a basic GPS of one sort or another for the last twenty years. Generally I don't use it. I still prefer to plan on paper then sail by eye. As long as I can see landmarks going by I can concentrate on the sailing and occasional hazard avoidance. I very rarely need to know exactly where I am or when I might theoretically get somewhere, and if I do then rough calculations do the job. An open sea passage needed them even less, as noting the GPS position every few hours gives a really good rolling start to any potential need to use dead reckoning.

So by all means use only electronics - you will probably build up the same competence to ignore them and concentrate on boating, except for a few rare occasions. Just make sure tide tables are included for planning.

 

[AntarcticPilot]

This may be worth a mention: http://www.dft.gov.uk/mca/mcga07-ho...s/mcga-mnotice.htm?textobjid=13F6FC6E98771089

That is a very useful and timely link. GPS CAN fail, and may do so especially this year.

One group of scientists I used to work with were concerned with Solar - Terrestrial links, and it has been a routine part of my mental equipment for many years that satellite based systems rely on a quiescent sun. When GPS was a bright new toy in the early 1990s, there wasn't a full constellation, nor were receivers as sophisticated as now. So, to get geodetic accuracies, you had to plan to record several hours worth of signal at a time coinciding with when satellites were above your horizon and the horizon of a base station. Several times such observations were found to be useless because of ionospheric disturbances.

GPS, while a wonderful system and remarkably reliable is actually also very fragile, and can be knocked off its perch quite easily.

 

[AntarcticPilot]

Nobody is going to forget how to calculate two simple vectors where the inputs required are self evident there's plenty of thinking time because the vessel is travelling at a fast walking pace. And I'm speaking as someone who is helpless without in car sat nav.

They only have the luxury of forgetting if they knew it in the first place. I don't know if it comes in today's A-level syllabus, but vector maths certainly isn't covered below that level. Even if you've got A-levels, maths doesn't have to be one of them, so I'd guess a lot of people have never learnt how to do it at school. Even amongst those who have done A-level maths, how many people who don't use vector maths professionally can remember it?

 

[jrc1983]

That is a very useful and timely link. GPS CAN fail, and may do so especially this year.

One group of scientists I used to work with were concerned with Solar - Terrestrial links, and it has been a routine part of my mental equipment for many years that satellite based systems rely on a quiescent sun. When GPS was a bright new toy in the early 1990s, there wasn't a full constellation, nor were receivers as sophisticated as now. So, to get geodetic accuracies, you had to plan to record several hours worth of signal at a time coinciding with when satellites were above your horizon and the horizon of a base station. Several times such observations were found to be useless because of ionospheric disturbances.

GPS, while a wonderful system and remarkably reliable is actually also very fragile, and can be knocked off its perch quite easily.

Quite so. It's also worth mentioning that many of the GPS satellites in use are approaching 'retirement' age, and the Yanks are a bit unsure as to how they'll fund the replacement. People will often say "ah, but what of Galileo and GLONASS", forgetting that solar activity which causes bother to GPS will do the same to other satellite systems.
Was it 2003 when we had serious solar flare problems which had a very real affect on GPS reliability? If I wasn't such of an emotional cripple I'd be seriously worried as to just how much faith and reliance the world places on GPS.
Of course, any navigator (amateur or professional) worth their salt will never rely on a single position fixing system, it's poor seamanship.

 

[jbweston]

I'm an old guy who uses both GPS chartplotter and paper charts at the same time. I agree with most of what has been said here.

Another factor is the potentially hypnotising power of electronics. Someone said above (more-or-less) 'who nowadays adds up without a calculator'. Well, to use a calculator properly, it's helpful to be able to know whether the answer it's giving you is in the right ball park. I'm not claiming we need to check that the electrons are working, simply that we've keyed in the sums right.

Two true experiences which I found salutary.

1. Many years ago in the 1970s my mum sent me out to buy 10 avocados from Sainsburys. They were something like 40 pence each (the exact figure doesn't matter). At the checkout the assistant rang them through and the total came to £3.60. In those days you didn't get bogoffs, so I said 'I think it's £4.00 - ten at 40p'. The answer was if I wanted to query the price I'd have to talk to the manager. I backed down and accepted that 10 x 40p is £3.60. I have no doubt whatever that a checkout assistant (or any of us in our work) can do a better job if we can manage some basic arithmetic. It's what pilots call a 'gross error check'. Only an idjut with time on his hands does long division and manual calculation of square roots on paper if he has a calculator available. But only another sort of idjut punches the keys and accepts whatever the calculator says without a rough check on the answer, in case he punched the wrong keys.

2. When I learned to fly (1990s) we did the manual chart computer thing. Then we got a great GPS for the aircraft - brilliant new technology, complete with database of useful waypoints, but no moving map. To learn to use it, I practised on the ground. Near us one of the radio beacons is 'Trent' and then had (perhaps still has ) an ID of 'TNT'. I punched in TNT as my destination (expecting it to say 30 miles 300 degrees magnetic, or some such). What it said was 700 miles 135 degrees - and it was absolutely right. It was giving me the course to the beacon at Trentino in Italy, also 'TNT'. That was my error, not that of the system. Happily (a) I wasn't flying an aircraft and (b) I knew enough of the art of coarse navigation not to fly where it told me.

I've no doubt that the OP is well capable of some basic common sense checking - if his various plotters all tell him his next waypoint is 300 miles east of the Clyde, he has the gumption not to tell the helmsman to quit arguing and just steer straight for it. The point I'm making is that in training, a really useful thing for the instructor (and any RYA examiner) to do is to help the student hone his common sense navigation and pilotage skills, and sometimes to do that it's necessary to reduce reliance on the seemingly-infallible e-gizmo. Then when there's no instructor and he uses the e-gizmo (as many of us do) he'll get it to touch its forelock to him, rather than the other way round.

 

[AntarcticPilot]

2. When I learned to fly (1990s) we did the manual chart computer thing. Then we got a great GPS for the aircraft - brilliant new technology, complete with database of useful waypoints, but no moving map. To learn to use it, I practised on the ground. Near us one of the radio beacons is 'Trent' and then had (perhaps still has ) an ID of 'TNT'. I punched in TNT as my destination (expecting it to say 30 miles 300 degrees magnetic, or some such). What it said was 700 miles 135 degrees - and it was absolutely right. It was giving me the course to the beacon at Trentino in Italy, also 'TNT'. That was my error, not that of the system. Happily (a) I wasn't flying an aircraft and (b) I knew enough of the art of coarse navigation not to fly where it told me.

That's a very good point. I have had a similar thing happen on my boat! I was sailing single-handed and went below (yes, my chart-plotter is at the chart-table; we've had that discussion) to tell it to take me to a waypoint on the track. I was heading in roughly the right direction, and expected a gentle turn of maybe 10 degrees or less. Put it in and got a violent turn through about 90 degrees! Fortunately plenty of sea-room, and of course nothing near me - I wouldn't have gone below otherwise. I put the tiller-pilot on standby and steered by hand for the rest of the day! But I had selected the adjacent waypoint from a menu (I wanted "Toward Point" and GOT "Tarbert"!) - and it happened to be the other side of the Cowal Peninsula . Of course, I realized something was wrong immediately, and I'm sure everyone else would have too. But if I HAD been trusting the electronics, I might not have realized immediately that something was wrong, and in thick weather maybe I would not have realized until the rocks were a bit too close for comfort.

 

[AntarcticPilot]

Quite so. It's also worth mentioning that many of the GPS satellites in use are approaching 'retirement' age, and the Yanks are a bit unsure as to how they'll fund the replacement. People will often say "ah, but what of Galileo and GLONASS", forgetting that solar activity which causes bother to GPS will do the same to other satellite systems.
Was it 2003 when we had serious solar flare problems which had a very real affect on GPS reliability? If I wasn't such of an emotional cripple I'd be seriously worried as to just how much faith and reliance the world places on GPS.
Of course, any navigator (amateur or professional) worth their salt will never rely on a single position fixing system, it's poor seamanship.

And indeed, WHAT about Galileo and GLONASS? Most of our receivers can't use them anyway; the systems aren't compatible at that level.

 

[PhillM]

Found it:

http://www.professordavidlast.co.uk/cms_items/f20130501100051.pdf

2nd page.....


At present the primary electronic position input for maritime navigation is GPS and GPS is known to be vulnerable to intentional and unintentional interference......

... So it can be seen that maritime navigation is heavily dependent on GPS now and this produces a single point of failure – the very opposite of resilience.


CONCLUSIONS
 Maritime navigation is heavily dependent on GPS at present.
 e-Navigation is the future digital concept for the maritime sector, but must be supported by resilient systems
 GNSS has vulnerabilities and a complementary system is needed for resiliency. eLoran is the only proven system that can provide that resiliency. A business case has shown that eLoran could produce substantial cost savings through rationalisation of physical infrastructure.
 The GLA have demonstrated the perfromance of eLoran in UK waters and have begun to implement it on the East coast with Initial Operational Capability.
 eLoran has applications across many sectors, in support of critical infrastructure and the cost does not need to fall on the maritime sector alone.

 

[Deleted member 36384]

I never said I didnt calculate the course first!! I did it all properly! Just really discussing how to carry it out!

Okay, cool man!

 

[Seatrout]

On a wild and windy night one November around 0200hrs while sitting in a car on the seafront, I heard the unmistakable noise of a Chinook helo. It came closer and closer and bizarrely landed on an open piece of land nearby. Even more bizarrely, one of the crew got out and walked towards me.

"Hey mate, is Macrahannish nearby?"
'No it's about 50 miles to the west. This is Helensburgh."
"We just came up from England and landed to look for a road sign. Effing cross wind! Thanks mate."

He returned to the helo and with that they were off.

<This happened! I was sober then and am sober now!>

 

[AndyJ76]

On a wild and windy night one November around 0200hrs while sitting in a car on the seafront, I heard the unmistakable noise of a Chinook helo. It came closer and closer and bizarrely landed on an open piece of land nearby. Even more bizarrely, one of the crew got out and walked towards me.

Bit of a thread drift, but at a talk from a Chinook pilot, they said that for their low-altitude manoeuvres it wasn't so much "How high are those trees?", but "Is that gate open?"

 

[lustyd]

Playing devils advocate here a bit but I've never read about a soggy plotter threatening to sink a vessel by blocking a bilge pump. Paper on the other hand....

 

[Uricanejack]

The reason for NOT relying on electronics is that you have a single point of failure. OK, you've got several GPS capable devices, so you're taking sensible precautions against electrical failure on all of them at once. However, a lightning strike would probably take them all out, unless you are prescient enough to put them in the oven (which would act as a Faraday cage, and protect them). Said lightning strike (or engine failure or major electrical fault) might also kill the electrical system on the boat; no means of recharging notoriously power-hungry devices. On longer passages, electronics are relatively fragile and it is not unknown for multiple GPS systems to break down.

However, a far more likely point of failure is that there are times and places where GPS doesn't work. The armed forces deliberately jam GPS from time to time; this is notified in NOTMs. Mostly in remote places, such as the NW of Scotland, but occasionally Wales or the West Country. In fact, GPS transmissions are so weak that even a noisy bit of electrical gear COULD jam GPS locally. I'd imagine a faulty alternator might well generate enough RF rubbish to effectively jam GPS on the same vessel or nearby vessels. The radio signals from the satellites are incredibly weak.

Finally there are also natural events that would wipe out GPS; major solar storms would do that, and this mode of failure might well give misleading positions, not merely no position. There would also be little notice of an event like that; perhaps half an hour in the worst case (which is enough for aviation to be warned, but not enough for us!).

Even with multiple GPS equipment, you're still relying on something that has single points of failure. Unlikely ones, I will grant, but not impossible. So you ALWAYS need to be able to navigate without it.

The easiest way of both answering your original question and ensuring you can always stay out of trouble is to know where you must not go. So, knowing "I will be in danger if I go north of point X, or I must stay south of the line between P and Q" and similar things will allow you to give directions such as "OK, keep her as high as you can until X is on the beam (or whatever), then we'll need to tack", or "OK, we must tack now, and then keep as high as possible."

Incidentally, unless I have specified otherwise, I would expect the helm of a yacht going close-hauled to windward to be steering as high as they could, not a compass course. You can easily drop back down to leeward; you can't easily regain ground lost to leeward. Downwind is more a matter of the individual yacht and the sails set.

Navigation isn't just about knowing your position. It's about situational awareness. A paper chart is a better tool for that than a chart-plotter; it gives a better overview of the area and allows you to get the context of "where you are" much better than a plotter (with limited or even very small display area) can. The chart-plotter is far better at integrating information from many sources. But the point is that they do different things; one allows you to see the "big picture", and plan things like clearance lines and so on; the other gives you precise information about where you are, how fast and in what direction you're moving and so on. It isn't either/or, it's both. Your comparison with your paperless office isn't valid; it is true that (as long as you don't have a power-cut) you can do everything with an electronic document that you can do with a paper one (except things like signatures for legal purposes, for example). But charts and chart-plotters do different jobs. If I had to choose one or the other, I'd chose the chart over the chart-plotter; you CAN do everything a chart-plotter does on a chart (just not as quickly), but not vice-versa.

+1 some of the best advice so far.

 

[scottie]

But from a local perspective on the Clyde having the chimney knocked down may be of more harm than losing GPS signal!

 

[Deleted member 36384]

Playing devils advocate here a bit but I've never read about a soggy plotter threatening to sink a vessel by blocking a bilge pump. Paper on the other hand....

Surly everyone has a chart room at the back of the bridge which is well clear of bilges?