Navigation Style for Day Skipper - Advice from Instructors?

[Uricanejack]

I don't know about others, but I have been professionally involved with map-making and geographic information for over 30 years, and have used position fixing of many different kinds. I am long-time user of IT, have been responsible for Geographic Information Systems in a large organization and am a respectable software developer. I tend to be an early adopter of technology; I am no luddite.

But I believe that paper maps and Chart-plotters BOTH have a part to play in navigation. They do quite different jobs. Given that the paper chart is more durable and has fewer external requirements in the environment of a small boat, it makes sense that the set of skills required to use one is developed. That same set of skills will give better understanding of the principles involved, allowing better understanding of the chart-plotter's strengths and weaknesses.

Ultimately, navigation takes place behind the eyes of a navigator. Anything else that you use - chart-plotter, chart, GPS, AIS, radar, sextant, compass or whatever - is merely providing inputs to the navigational process that is taking place in an intelligent mind. Of course, if you have a chart-plotter (and I do), we make use of it! But I ALSO make use of the chart, my eyes (and local knowledge), and everything else that is available to me. Someone who is learning navigation needs to know the principles which inform the PROCESS of navigation, and not merely in case the electronic tools are not available. Chart-work teaches principles, which are essential to educate the navigational mind.

I tend to agree that some exercises are too artificial to be realistic - but at least doing the exercise will teach you something about limits of accuracy!

+1 agian

 

[prv]

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

Some of them can though - apparently the Russian government charges a tax on anything imported to their country that speaks GPS but not GLONASS. This has reportedly been effective in getting the technology into real devices, in particular mobile phones. The iPhone has GLONASS from the 4S onwards.

How it actually handles switching between them, or resolving disagreements in position, I do not know.

Pete

 

[dunedin]

Of course if the vis is good you won't need either a GPS position or an EP in the Clyde cos you can see where you are!

Nicely pragmatic - and brilliantly posted by the owner of the original Mark-1 Eyeball.

Leaving from Largs and sailing the Clyde my usual navigation instructions to the helm are
- sail on the wet bits
- avoid the hard bits
- tell me if depth goes below 20m

Worked so far (though not recommended on West Coast amongst rocks and tides, or cross Atlantic.

PS. You may deduce I haven't done Day Skipper or other RYA courses (though believe may have the first certificate of Higher Navigation from school ;-)

 

[grumpy_o_g]

Thanks for that!!

But I would be interested what Private Pilots get taught. Is there such an emphasis on doing the nav with no electronic aids??

Depending on the level/experience of the pilot I'd say generally there is. A PPL should be able to fly in VMC with no instruments at all (not just no Nav), just a map, a throttle (if it's power) and a stick and rudder pedals. It's a bit different though as flying is more complex in terms of airspace restrictions, what happens if you can't find your destination, etc. and it's much harder to get an aeroplane to look after itself while you get your act together.

 

[lustyd]

Some of them can though - apparently the Russian government charges a tax on anything imported to their country that speaks GPS but not GLONASS. This has reportedly been effective in getting the technology into real devices, in particular mobile phones. The iPhone has GLONASS from the 4S onwards.

How it actually handles switching between them, or resolving disagreements in position, I do not know.

Pete

The signal is still just time so I think ultimately it just ends up with more satellites to make a single position. I doubt under normal circumstances the atomic clocks will disagree by much so unless there is a pretty big war we're probably ok. The claimed accuracy for the euro one is now in cm too and I read recently that all currently available chips now support all 3 systems.

 

[DaveS]

Rely on GPS only and any of these could really spoil your day

http://www.jammer4uk.com/car-gps-jammer-c-1.html

I seem to recall somthing in the press about adding a radio beacon for shipping in the Dover strait because there were so many cars on ferry and in containers that were using one. Could be an urban myth of course.

My anti-virus software reports a problem with that link.

 

[AntarcticPilot]

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

But that's no longer my "home" marker! Tail of the Bank buoy is nowhere near so visible.

 

[laika]

a) How do you tell the helmsman which course to steer when you are tacking or gybing?
b) How often should I be going below to sneakily check my phone without the instructor noticing? As I find it much easier to use than the chartplotters (and before anyone tells me I shouldnt rely on it, I can assure you that when I am cruising with friends we have 2 phones with Navionics, a Nexus 7 with Navionics, a laptop with OpenCPN and raster charts and a seperate GPS and real charts!).
c) How should I impress my next instructor with my navigation skills!!!?!

In reverse order...
c) You're being tested as a skipper, not a navigator. You should (and state that you do) know navigation already. This means the most important thing is being in charge, having fun and making sure everyone else is having fun which means
b) You should be going below as little as possible and ideally not at all: you aren't seeing everything that's happening when you're at the chart table. *Skippering* the boat is what it's all about: being in control.

Dayskipper "passages" are (unless things have changed) pretty short. Barely more than pilotage out, a short hop and pilotage in. Your eyes are the primary nav device. As several people have said, the most important things is to work out where the dangers are and how to make sure you know how to avoid them (transits, clearing bearings, depth contours: write this info down in your notes you shove in your pocket as well as memorising it) then sail in the wet bits in the direction you want to go. Always know roughly what the tide is doing.
a) Best course, as everyone says, then see what "best course" is. When there's no dangers and everyone's happy, it's ok to go plot your current course and work out where to tack/gybe (ie depth contour, transit, such and such abeam etc) assuming you're in an area where there's so few other boats you may actually sail a straight course to that point.

You may have been told not to over-navigate. That's hard to grasp if you're pretty good at theoretical navigation but it's true: If your course has just been mucked up by a racing fleet and you can see your destination, don't go down below and plot a course to steer (you showed you could do that before you set out). Modify the bearing by a rough factor for tide and a little bit for leeway and sail that if you can. Avoiding the dangers you've noted down.

It really isn't an exact science and as long as you know how to stay well out of danger it's better to be on deck and in charge as much as you can than be super-precise with your nav. I was going to say "than reach your destination 5 mins earlier" but on deck you'll be able to give the crew the benefit of your mad helming and trimming knowledge so you may even get there quicker.

To overstate the point, the RYA practicals are about *skippering*. Be visibly in charge and inspire confidence. Checking your phone (or plotter) every 5 mins makes people think you're not sure where you are, what you're doing or whether your plan is working out.

 

[alant]

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?

I didn't realise that a CTS, was A level maths!

 

[prv]

I didn't realise that a CTS, was A level maths!

It would be if you calculated it numerically (insert sad comment on the content of GCSEs here if you wish). But I've never come across anyone who does that; most, myself included, work it out "by construction", ie by drawing to scale and then measuring. That's certainly below A level, probably below GCSE standard.

Pete

 

[Uricanejack]

I did O grade math in Scotland several times before success. Vectors were covered and like most of the rest of the syllabus I paid little attention and was sure it would never be any use in the real world. I had pretty much the same thoughts about trigonometry, algebra, geometry and as of old dead Greeks like Pythagoras I couldn’t have cared less.
Then I took up sailing.
Math with an actual purpose all of a sudden it started to make sense and was actually interesting and fun.

 

[Uricanejack]

It would be if you calculated it numerically (insert sad comment on the content of GCSEs here if you wish). But I've never come across anyone who does that; most, myself included, work it out "by construction", ie by drawing to scale and then measuring. That's certainly below A level, probably below GCSE standard.

Pete

At times I find it quicker and easier to calculate rather than to plot.
I often choose to use tables rather than calculator. I find them quicker. Showing my age I guess.

 

[[70521]]

Math with an actual purpose all of a sudden it started to make sense and was actually interesting and fun.

+1

 

[jrc1983]

At times I find it quicker and easier to calculate rather than to plot.
I often choose to use tables rather than calculator. I find them quicker. Showing my age I guess.

The new generation generally exhibit a look somewhere between disbelief and horror when I pull out Nories and work through the log tables instead of using a scientific calculator.
What flummoxes them even more is that I can generally do it quicker than they can rattle all the numbers into their calculator!

 

[AntarcticPilot]

It would be if you calculated it numerically (insert sad comment on the content of GCSEs here if you wish). But I've never come across anyone who does that; most, myself included, work it out "by construction", ie by drawing to scale and then measuring. That's certainly below A level, probably below GCSE standard.

Pete

I too would normally do it by construction; that's the way I leant it before I did the vector stuff! But knowledge of vector triangles helps enormously in making sure you apply the construction correctly.

Agree wholeheartedly with those who suggest that having a reason for learning maths makes it a lot easier to learn! I happen to have been fortunate and was taught traditional euclidean geometry, and that has been incredibly useful for all sorts of navigational purposes. And I was lucky enough that spherical trigonometry found a purpose soon after I was exposed to it; that is surprisingly useful in all sorts of disciplines you wouldn't imagine - it was actually crystallography that first really extended me in that field!

Indeed, I was lucky that I learnt maths BEFORE the "modern maths" came in. When I were a lad, maths was taught as a tool for use in other areas of life, rather than as a stand-alone subject. So, I didn't cover a lot of subjects that are taught now (set theory and such-like), but I did do a lot of practical things. Oh, and I had to do compund interest sums in £sd!

 

[prv]

The new generation generally exhibit a look somewhere between disbelief and horror when I pull out Nories and work through the log tables instead of using a scientific calculator.

I'm of the generation that did A-level maths with a graphing calculator, but for interest's sake our teacher did take a lesson to show us how to do stuff with log tables. Not that I can remember it now.

We once found a stash of slide rules in the back of a cupboard in one of the old physics labs, and after asking the teacher how to use one (yes, we did know what they were!) some of us did our calculations for the rest of the lesson using them, just for the novelty.

Interesting historical asides, but I'd still use a calculator (or a computer) for real work

Pete

 

[AntarcticPilot]

The new generation generally exhibit a look somewhere between disbelief and horror when I pull out Nories and work through the log tables instead of using a scientific calculator.
What flummoxes them even more is that I can generally do it quicker than they can rattle all the numbers into their calculator!

It's not surprising you're faster - the tables use specialized pre-calculated functions; the calculator only provides general purpose ones. So there are probably more steps involved in using a calculator. Distance off, for example - it's one look up in a table; it's quite a few key-presses on a calculator.

 

[AntarcticPilot]

I'm of the generation that did A-level maths with a graphing calculator, but for interest's sake our teacher did take a lesson to show us how to do stuff with log tables. Not that I can remember it now.

We once found a stash of slide rules in the back of a cupboard in one of the old physics labs, and after asking the teacher how to use one (yes, we did know what they were!) some of us did our calculations for the rest of the lesson using them, just for the novelty.

Interesting historical asides, but I'd still use a calculator (or a computer) for real work

Pete

Crikey, you're young! We were allowed no artificial aids to computing at O-level (log tables were permitted in some exams for which they were provided; otherwise they counted as artificial aids) and slide rules were allowed in some exams at A-level (I'm sure others remember the special deal with British Thornton that was pretty much mandatory!).

Using a slide-rule pretty quickly teaches you about rounding and cumulative errors! And at best three significant figure accuracy.

I think that at the end of my A-level years, there were a few fantastically expensive electronic, 4-rules pocket calculators available - much too expensive and delicate for school use. In my first job (post A-level, pre University), the company I worked for had a "computer" that was the size of an office desk. It did pretty much what a programmable calculator (without graphics) would do today. I don't know if it did mathematical functions such as sine and cosine - I suspect it didn't!

 

[Babylon]

...Math with an actual purpose all of a sudden it started to make sense and was actually interesting and fun.

We did vectors when I was thirteen. Our maths master, a control-freak bible-basher who really didn't like ethnic minorities (which was unfortunate as the school was 50% Asian/Black/Jewish/Chinese/etc), used the relatively straightforward example of a man crossing a road while a car came driving down the road at the same time, before going onto the more advanced stuff.

Later that year, on a 24 mile sponsored walk, he applied a not-unrelated method to sneak up behind me and ram his hobnailed boot up my arse!

One never quite forgets one's teachers...

 

[lustyd]

Crikey, you're young! We were allowed no artificial aids to computing at O-level (log tables were permitted in some exams for which they were provided; otherwise they counted as artificial aids) and slide rules were allowed in some exams at A-level (I'm sure others remember the special deal with British Thornton that was pretty much mandatory!).

Using a slide-rule pretty quickly teaches you about rounding and cumulative errors! And at best three significant figure accuracy.

I think that at the end of my A-level years, there were a few fantastically expensive electronic, 4-rules pocket calculators available - much too expensive and delicate for school use. In my first job (post A-level, pre University), the company I worked for had a "computer" that was the size of an office desk. It did pretty much what a programmable calculator (without graphics) would do today. I don't know if it did mathematical functions such as sine and cosine - I suspect it didn't!

I think this post nicely brings us back to the OPs point. Nobody would suggest doing exams (let alone the actual job you'd eventually get) these days without electronic aid because it's unnecessary to do all of that work. The electronics, when used in schools, allow a greater breadth of information to be studied, and more advanced topics to be covered, and hence the students can leave with a deeper understanding even if they are unable to do things the old fashioned way.
Unfortunately, with plotters (and even VHF), very few people actually know how to use them to their full potential and especially traditionalists like many instructors. This is what gives the impression that the old ways are in some way better but eventually the attitude dies off and electronics are embraced. With the shipping community on the cusp of ditching paper charts, production costs will rise for leisure paper charts which will lead to their demise in the next 10 years or so. At this point everyone, even the traditionalists, will suddenly realise the virtue of electronics