GPS

O

oldsaltoz

Well-Known Member
Joined
4 Jul 2001
Messages
6,005
Location
Australia, East coast.
Visit site
Plotter, radar and spare GPS on board. Also a full set of up to date charts and instruments including 2 hand bearing compasses.

All of the above require power and protection from Lightning, no way to be sure that is possible.

Also good to your hand in.
 
I fly light aircraft.

A long running debate in that arena is the use of charts and traditional navigation techniques.

There is a school of thought, to which I subscribe, that charts should / can be assigned to the flight bag to gather dust. The aircraft I fly is all "glass" - in other words two screens display all the information I require including charts driven by twin GPS.

For long distance sailing can the same be said? It seems to me with kit like Raymarine's E series driven by GPS with another backup there is very little need for traditional navigation techniques and while there is a risk in extreme of it all failing presumably the risk is very small.

What do people think?
 
You are worrying me now. I thought aircraft were navigated by proper inertial navigation systems.
Click to expand...

Yes, most commercial aircraft do have inertial navigation. In fact it is far less accurate than GPS by a factor of many 100s over a transatlantic crossing.

These days in light aircraft most people use GPS for primary navigation with VORs as a fall back. Even GPS approaches are widely used in the States and a few have been approved in Europe where the sole means of navigation is GPS although you need to be visual at around 700 feet.

The vast majority of my flying is using GPS as the sole means of navigation and of course when flying if you are in or above clouds charts are not much use anyway.

Seems to me if it is good enough for that purpose it should be good enough for blue water sailing? I wonder?
 
PeterC said:
There is a school of thought, to which I subscribe, that charts should / can be assigned to the flight bag to gather dust. The aircraft I fly is all "glass" - in other words two screens display all the information I require including charts driven by twin GPS.
Click to expand...

The only paper chart I carry is mounted in a picture frame on the bulkhead. Its of my local area and is there only to satisfy survey requirements.
 
Plotter Only Navigation With No Paper Charts Onboard - Yes And Likely To Be The Norm

Navigating by Chart Plotter only is completely realistic and safe. For it to be accepted as normal there would probably have to be appropriate back up systems in place; 2 x plotters and 2 x power supplies as a suggestion, where one power supply was a dedicated power supply for navigation equipment only. Probably would end up with a "standard" by some Governing body.

I personally don't want to rely only on electricity to navigate with and actually enjoy the independence that navigating with paper charts gives.
 
PeterC said:
Yes, most commercial aircraft do have inertial navigation. In fact it is far less accurate than GPS by a factor of many 100s over a transatlantic crossing.

These days in light aircraft most people use GPS for primary navigation with VORs as a fall back. Even GPS approaches are widely used in the States and a few have been approved in Europe where the sole means of navigation is GPS although you need to be visual at around 700 feet.

The vast majority of my flying is using GPS as the sole means of navigation and of course when flying if you are in or above clouds charts are not much use anyway.

Seems to me if it is good enough for that purpose it should be good enough for blue water sailing? I wonder?
Click to expand...

The problem from the perspective of "blue-water" sailing is the perennial one of power supply. An aircraft can pretty well guarantee there will be power - if you haven't got it, then knowing where you are is the least of your problems as where you are going is down! But a sailing vessel on a long passage can't guarantee power to the same level of reliability - and a boat will keep floating and sailing even if the power supply is dead.

Further, a boat is a bad environment for electronics, even those designed for the task. You cannot guarantee the reliability of an instrument that may have to work for weeks on end in the same way that you can guarantee the reliability of an instrument that at most has to work for 12 hours on end.

So, while GPS is great for convenience and is what most of us use on a day-to-day basis, we need backup techniques that don't rely on electricity. For oceanic passages, that means astro-navigation, which just needs a sextant, tables and a time source - almost any digital watch these days is good enough. Latitude doesn't even need the time-source.

In any case, there are issues around feeling a sense of continuity with the past!
 
AntarcticPilot said:
The problem from the perspective of "blue-water" sailing is the perennial one of power supply........ we need backup techniques that don't rely on electricity........
Click to expand...

I am pretty sure that a reliable electrical power supply with back up can be put together with existing technology that is more reliable statistically than cloudy versus non cloudy days. Its just a matter of acceptance.

At the end of the day if you had total electrical failure you could keep sailing on your compass course until a certain DR position and then switch on your battery powered back up GPS /plotter for that final bit. The scenario is no different from dropping over board your only sextant and then sailing on until you can fix the yachts position with hand bearing compass.

Personally, I agree with you ArticPilot but I have noticed since joining this bl**dy forum that I have started to become anchored to certain paradigms, which I find are limiting. Maintaining the status quo while expecting improvement is a definition of insanity, my senility is I hope many years away yet.
 
NDG said:
AntarcticPilot said:
Latitude doesn't even need the time-source.

QUOTE]


Is that correct? Its a long time since I learnt a bit of astro-nav, but I thought a sight for lat needed to be done at midday (or some other known time)?

Could be wrong.
Click to expand...

You determine Midday by observing the maximum elevation of the Sun, and of course the Sun is due north or south at midday. You can anticipate when to start observing by using very crude time-keeping (they used sand-glasses in the sailing navy days!).

Then it is just a matter of very simple addition and subtraction to get latitude.

Alternatively you can get latitude at night by observing Polaris; although Polaris isn't quite at the celestial pole, it is near enough for the accuracy of observation from a small vessel.

Once you have latitude, you can use the time-honoured technique of "running down the latitude"!

And I doubt if there is a reliable method of ensuring power supply on a sailing vessel, short of installing a nuclear thermo-electric generator. Anything with moving parts can fail from mechanical causes, or by stress of wind and sea. And electricity and salt-water don't mix, in exciting and interesting ways. Sailing boats present a perennially damp and salty environment, even on a marina berth!

DR on a sailing vessel can rapidly accumulate errors that make it only slightly better than sticking a pin in the map while blind-fold.
Click to expand...
 
Personally - electronics any day! Paper charts? Got them but have not used them for many years and hope to never use them? Personally I get no enjoyment or satisfaction navigating using a paper chart, in the same way I get no pleasure whatsoever using an AA roadmap when driving my car. My boat and my car have satnav - no hassle, dead reliable, accurate and takes away a chore, so I can relax and enjoy driving my boat or my car. BTW there are many ways to engineer a reliable installation, so worrying over equipment failure shouldn't be a necessary.
 
asteven221 said:
Personally - electronics any day! Paper charts? Got them but have not used them for many years and hope to never use them? Personally I get no enjoyment or satisfaction navigating using a paper chart, in the same way I get no pleasure whatsoever using an AA roadmap when driving my car. My boat and my car have satnav - no hassle, dead reliable, accurate and takes away a chore, so I can relax and enjoy driving my boat or my car. BTW there are many ways to engineer a reliable installation, so worrying over equipment failure shouldn't be a necessary.
Click to expand...

Its interesting how people's preferences differ. I take a completely opposite approach - its just a personal thing - I like maps and charts and enjoy using them, even a roadmap in a car. They always give a good sense of one's position in the world. I do have a GPS on the boat but I use it to plot positions straight onto a paper chart, but that's about it. I can't imagine anything worse than having a satnav in the car. I like using modern technology - I've got the ipods and digital cameras etc - I just find charts interesting. Its always nice to look at my English Channel passage chart and look at all the old plots and courses over the years that have given it a nicely well-used appearance, and remind me of passages we've made in the past. Dont get that with chart plotters!
 
NDG said:
Its interesting how people's preferences differ. I take a completely opposite approach - its just a personal thing - I like maps and charts and enjoy using them, even a roadmap in a car. They always give a good sense of one's position in the world. I do have a GPS on the boat but I use it to plot positions straight onto a paper chart, but that's about it. I can't imagine anything worse than having a satnav in the car. I like using modern technology - I've got the ipods and digital cameras etc - I just find charts interesting. Its always nice to look at my English Channel passage chart and look at all the old plots and courses over the years that have given it a nicely well-used appearance, and remind me of passages we've made in the past. Dont get that with chart plotters!
Click to expand...

I work with maps as my day job, both making them and using them. It is, like most things, horses for courses. The paper map is the ideal product for some applications; the digital map for others. For leisurely planning, the paper map is much easier to use; for instant decision making, the digital product is better. The digital product allows direct integration with other systems - no "plotting positions" at all! But the paper product shows all the topography in its overall context. A digital map zoomed enough to be useful for immediate navigation does not show an overview; and vice-versa. It isn't better or worse; it is different products for different use patterns.

By the way, it is something of a false distinction these days. Pretty much all modern charts are created and maintained in digital form; the paper product is an output from the digital data. For vector digital products, the digital product should have as much or more detail than the printed chart. This may not be true for raster products.
 
NDG said:
Its interesting how people's preferences differ. I take a completely opposite approach - its just a personal thing - I like maps and charts and enjoy using them, even a roadmap in a car.
Click to expand...

I'm with you, brother. I don;t have a chart plotter and I have no intention of getting one - for a start, I can't see how even a huge (sic) eight-inch screen can begin to compare with a proper waterproof daylight viewable, take into the cockpit in the rainable paper chart. I'm a purist there too - no Imray, no pretendy "Small Craft" stuff, only proper, decent, god-fearing admiralty charts on board. Hah.

Mind you, it's GPS every time for finding positions.
 
Having been trained when radio aids really were aids (Decca was still plotted on Lattice charts) I am basically very much a 2b pencil and chart man, but there is no doubt that GPS is a boon and after several years with a basic hand held I have craduated to a plotter and as a back up a lap top with GPS and a different charting package (a back up is not independant if it shares resources). One of the handhelds will sit in the grab bag and the other in the chart table drawer. I will of course keep my paper charts, there are times when seeing the big picture clerly has it's plus points.

I was also trained to do pilotage in conditions where having a chart at hand was not practical so also can do such detailed preplanning with clearing bearings wheel over points etc.

I see no problems in using modern tools to do the job if you both ensure back up and the ability to revert to first principles
 
You must log in or register to reply here.

Other threads that may be of interest

Baggywrinkle
Test run of the Lithium system that has been sitting in my cellar for most of this year.
Replies
16
Views
631
Baggywrinkle
Baggywrinkle
W
Battery suicide
Replies
17
Views
660
Refueler
Refueler
R
My boat trip hopefully in May Around Scotland
2 3 4
Replies
65
Views
2K
RobBradley
R

Share this page

Top