GPS to Paper Charts

I useful tip that is related to this is when keeping track of position in case the GPS crashes.
Most people write down, or plot, their lat and long.

If you have known waypoint ( often the destination) remembering the range and bearing is easy. ( remembering lat and long is too difficult). This means there is no need to write down the position and if the GPS fails you will have a more up to date position to start DR from.

It's worth a try anyway. Works for me.
 
Commanding a classroom of keen DS theory crew as I do on Monday nights in the winter, I can guarantee it is quicker to plot bearing and distance to describe a position than lat and long....
 
It's amazing how old ideas get recycled periodically as the latest best way of doing something.

At least 15 years ago (could well be much more) Yachting Monthly (or was it PBO?) gave away a sheet of sticky backed 'compass roses' for sticking on your charts in convenient places and using in the way described in the video.

I used this method with an old Decca navigator and it works. However, these days I find it simpler (using just 1 GPS) to put in the destination waypoint so you always have the distance to run quickly available (important for reassuring the crew that we are making progress).

On a cross channel passage, the next most useful piece of information is the cross track error. At Springs mid channel this can reach 14 or 15 miles off the rhumb line (depending at what state of tide you departed) and is a very useful check of your calculated (estimated) eastings or westings. You can't get that from a compass rose waypoint, without first plotting and then physically measuring the XTE.
 
Last edited:
Playtime said:
It's amazing how old ideas get recycled periodically as the latest best way of doing something.

At least 15 years ago (could well be much more) Yachting Monthly (or was it PBO?) gave away a sheet of sticky backed 'compass roses' for sticking on your charts in convenient places and using in the way described in the video.

I used this method with an old Decca navigator and it works. However, these days I find it simpler (using just 1 GPS) to put in the destination waypoint so you always have the distance to run quickly available (important for reassuring the crew that we are making progress).

On a cross channel passage, the next most useful piece of information is the cross track error. At Springs mid channel this can reach 14 or 15 miles off the rhumb line (depending at what state of tide you departed) and is a very useful check of your calculated (estimated) eastings or westings. You can't get that from a compass rose waypoint, without first plotting and then physically measuring the XTE.
Click to expand...

i still have / use charts with them :o

so you dont plot on paper charts as well then :eek:
 
Last edited:
sailorman said:
i still have / use charts with them :o

so you dont plot on paper charts as well then :eek:
Click to expand...

I used to but don't anymore - all that rubbing out ruins the charts. :eek: :)

Instead I keep a written log every hour including lat, long, DTG and XTE. The paper chart is always ready on the chart table for the last log entry to be plotted in the event of electronics failure. However, in over 20 years of crossing the channel etc. I have never had a failure.

These days I use an old laptop for real time nav that also maintains an electronic track and log so I think I'm covered.
 
This is an intriguing thread, not for 'Sailorman's ( Tranona? ) concept - excellent though it is - but for the range of reactions. I am vividly reminded of my course at RAF Nav School, in the late 60s, when exactly this 'set' of concepts was introduced to us by our class tutor, with exactly the same range of arguments among us and consternation. We were focussed on the range of needs in air navigation but, surprisingly, the concepts are very similar if one has the capacity to think a bit 'contrarian'. And I like to suggest that navigation doesn't happen on a chart table - it happens between the ears.

We're exploring the differences, and the potential uses, relating to a rectilinear or 'Cartesian co-ordinates' system together with a 'polar co-ordinates' system, innit? They each have their merits and conveniences.....

I do like 'Sailormans' thinking about the task, and about how he can do it better and more conveniently for him. His approach gives him a sound tool he's comfortable using. He's quite right. And so are others, with others. The really important bit is thinking about your processes..... One can have several 'named/numbered' compass-rose Offset Waypoints stored in the GPS receiver, and switch between them in turn as the passage progresses. Contrary to popular opinion, there ARE other sea passages than the simplistic one between the Solent and Cherbourg.... Consider the passage from Hurst Narrows to St Marys/Isles of Scilly, how many Offset Waypoints would be useful, and on what headlands they should be.

I like to run complex pilotage when I can ( such as along the Chenal Meridional de Portsall ) 'cos I need the exercise, and utilise the convenience of having two GPS devices running together - one showing rectilinear co-ordinates ( Lat/Long ) and the other with each significant Turn Point as a Waypoint showing bearing and distance to run. Actually, on the latter, I usually have the 'dialled-in' waypoint about 50 metres or so from the physical feature, seamark or Breton concrete tower, which demarks the point at which I make a decision to turn, stop, or go back.

That process is remarkably similar to the process used by airliners navigating along the world's commercial Airways - Waypoint to Waypoint. In fact, the term also is borrowed from that arena.

This technique, of using Offset Waypoints, is just one of the multiple tools a good navigator should have in his skills toolbag, so he can select whatever suits his purpose best.

IMHO
 
sailorman said:
so you dont plot on paper charts as well then :eek:
Click to expand...

Only on passages over 50NM. I find on shorter passages I know my location well enough that I could safely get somewhere even starting with a "clean sheet". For instance, crossing the channel from IOW to Cherbourg you know you're somewhere on the line between the two, you know when you left and what speed you've been making, and you know what the tide was doing (because you'd have planned it). So you know your location within a few miles. Worst case - the entire yacht goes down, and for the sake of argument so does your mobile and your handheld GPS along with your handheld DSC which also knows where it is, and a satelite plunges into the briney mere feet from your stern, so you know that even if your kit were working you'd still be lost...

If all that happens, you work out roughly where you are and steer a course to one side of the destination, work out what lights you'll see first if at night, or just sail until you see land if in the day. You then turn towards the destination and sail in :)
 
You must log in or register to reply here.

Share this page

Top