Originally Posted by carstenb
I think I've written it before, but if not here goes.
Most charts (and all chart plotter electronic charts are based on the same information as paper charts) have data that is old. How old? Well in many european countries, the data was generated in the 1800's by sailing a ship at 100 meter intervals and "casting the log". This generated data that was then extrapolated and show the same depth between the 100 meter sailing lines. This means that if one run showed a depth of 6 meters and another run 100 meters away also showed 6 meters, then it was assumed that the entire area was 6 meters. In some areas of the world, charts are based on data supplied by Captain
Cook and his like.
So - these charts (and this is most charts) are, in and of themselves, unreliable or at the least based on incomplete data. In a recent court case, instigated by an insurance company, the hydrographic office won. The insurance company attempted to get regress on the office saying the chart did not show a series of rocks where a sailor smashed his boat
. The courts reasoning was that with the data collected as it was in the 1800's and since the hydrographic office also included a statement with each chart saying this, that no regress was possible.
If you turn on your electronic chart plotter, the first thing on the screen
is a statement saying that the charts shown are unreliable and you hereby agree that no regress is possible. By pressing enter you agree.
Just so we understand - the electronic chart is no more accurate than a paper chart. If both are updated then they are equal in accuracy.
Regarding which you like to use -this is a personal preference. I use both, quite happily and I can't see myself getting rid of paper any time in the future because it gives me a much better overview than I get with my plotter
This is a generalisation. For example in Europe
routes , sea ports
grounds etc, have been re surveyed with modern survey
techniques. Other places yes rely on old data or a combination of old and new data.
Because its easier to update electronic charts these are often well ahead of paper charts. As to manual updates I notice chart shops ( and these are now few and far between) are not necessarily updating all their charts. I got uncorrected ones as new.
You are incorrect as to your statement as to what you see on a chart plotter. My Garmin
makes no reference to such " unreliable" data at sign on. Some do and some don't. You certainly can't sign away your rights at the press of a button.
Furthermore your statement " the electronic chart is no more accurate then a paper chart" again is an incorrect generalisation. Almost all hydrographic offices have transitioned to digital methodologies. In most cases a combination of raster and vector storage
systems are used. Often modern vector data sourced from newer surveys IS more accurate then can be represented on a chart and hence when rendered correctly on a chart plotter provides better resolution or more clarity of detail. Equally unless you are carrying multiple paper charts including large and small scale of the same area , it's likely your plotter will contain more information then your paper charts. Furthermore companies like CMAP and Navionics
data ( like new marinas
etc) that are incorporated quickly into their digital offerings , yet take literally years to appear on paper charts. ( I seen this especially in Greece
and elsewhere) then there is the developing technology of " crowd sourced " data , a process that is not easily transferred to paper !!
Fundamentally hydrographic offices believe all future chart delivery
systems will be electronic. This doesn't mean the end of paper, but that paper will be clearly be the secondary process.
In my view, today it's virtually impossible , today, especially outside the US to sail without electronic charts. OF COURSE, one takes paper charts along, but my experience on many boats is that paper charts are typically small scale planning charts, few cruisers can afford the complete paper chart set anymore. Furthermore it's getting harder and harder to buy paper charts locally, few major ports
have a chart agent anymore. Chandeliers tend to carry a very restricted set. hence the Widespread and illegal ( outside the US) of making photocopies of others cruisers paper charts.
In my case as I do northern European and med sailing. I use almost exclusively IMRAY charts. These have the advantage of being durable, being good planning charts , with a few detailed ports , typically those useful to sailors. The cover a large area at a reasonable expense. They are however not really suitable for manual updating. Since they dont cover all the coasts in enough detail, I wouldn't set sail without a proper ( and considerably cheaper) electronic chart set. The is the only cost effective way to chart up for a long med passage
. I should add that I can use a sextant, but now it's just for fun.
I recently sailed from France
, sardinia, Sicily
, etc. I shudder to think how much a complete paper chart set of all those coasts would cost,, never mind the difficulty in sourcing them.
The fact is , electronic charts are the prime navigating instrument for most sailors , with paper charts being rightly carried as backup and typically used as route
planning aids. ( mind you this is being challenged by large screen laptop
planning aids )
I fully accept that in the US paper is cheaper then elsewhere and the print on demand system ensures availability. This may skew the debate in the US, but elsewhere were it not for electronics we'd be lost
!! . European hydrographic agencies are not following the US lead in on-demand printing , believing the jump to digital is inevitable. In fact most chart work
is now actually outsourced to commercial
companies, and hence has a significant economic factor. The days of the all powerful and ever present UKHO have like the Admiralty gone the way of the do-do bird
Note I am not aware of any significant numbers of countries in Europe
that require a leisure to specifically have paper charts. SOLAS V requires adequate charts be carried but it doesn't specify what type.
There is a self full filling prophecy here, ask any hydrographic office ( I'm involved in chart generation in a small way ) and the will tell you that the production of paper charts is loss making and increasing so, as their major commercial customers complete the transition to digital. Coupled with the significantly cheaper electronic charts and near universal use of digital charts in leisure vessels, spells a slow end to paper. Most hydrographic offices in the new financial dispensation now are required to turn a profit , they will follow their commercial customer demands, leisure users do not really register.
The RYA shore based Yachtmaster course now contains a significant element devoted to electronic charts and chart plotters including students being supplied with a custom RYA PC based chart plotter simulator. This recognises the reality of most sailors experience. In fact at a recent RYA powerboat instructors conference, a suggestion was made that the RyA Yachtmaster
( powerboat) course remove any paper chart instruction. thankfully this was not acted upon, but it shows the direction of thinking
In time I suspect looking at trends , a lot of secondary aids to navigation will go virtual, rendering paper problematic, digital charts will be updated over the internet( as they are now on many ships).
We can " tilt at windmills" but " progress" marches on.