MFD route logic.

[Just_sayin']

You have a route called A to G.

It could be CALLED anything, it makes no difference to the question. So let's call it Venus to Jupiter if necessary.

The route consists of waypoints A B C D E F G

You follow it and arrive at G.

Turn the MFD off.

You want to return and you see a Reverse Route option.

You select Reverse and yay the route is now G F E D C B A ... still called A to G or Venus to Jupiter. Again, the NAME is irrelevant.

You arrive at A, turn off the MFD ... go home.

Next trip you decide to go back to G from where you are ... A.

You select A to G.

What would you expect it to logically show, A to G or G to A?

 

[bedouin]

In older units I would have expected it to show G to A - I don't know if they have got cleverer since then

 

[James_Calvert]

G to A because that's how you left it last time.

 

[johnalison]

G to A because that's how you left it last time.

It may differ between units but mine does the same. It is a bit of a fiddle trying to check it in advance, so the easiest thing for me is to set it to follow the route, with goto to the first waypoint, when it is obvious how it stands and it is simple to 'reverse route' if necessary.

 

[EugeneR]

I'd expect A to G, which is how it was stored, with the option to execute it in reverse.

If you select that, it becomes the current route (which may persist after switchoff) which may itself be reversed again, to then become the new current route.

But, it does not overwrite the file you loaded it from, and when you re-load the original file, you start from A to G ,with the option to reverse again.

 

[shaunksb]

B to D.

Via F...

__________________________

 

[michael_w]

I thought it was Medium Density Fibreboard

 

[Just_sayin']

Thanks for the replies. My initial thought was that A to G would always be the stored route unless you reversed it "that day". Live.

Reversing the route, then turning off the MFD should to my mind have no impact on the STORED route but I do see the other argument too. Hence the ponder.

Précis .... young family, new boat, skipper with RYA Coastal, Brittany to UK, viz good, swell horrible, now hand steering, viz down to 5 miles, still "confident" ... the MFD is working and The Channel is clear, but he wanted the route. Thinks he hit reverse but it's a small symbol and the screen doesn't actually show the route flip round, now has a CTS back to where he started ... to join beginning of route G to A? or had it not reversed and it's on the original A to G ?

Being thrown around, family upset.

Lost confidence in the route so banged in GoTo waypoints, pre-Covid, not been to boat since.

Just shows the value of understanding your electronics but he had a crash course in understanding the radar, ais, vectors, trails, cpa's and so much more on just one screen he simply blanked.

 

[James_Calvert]

I learnt my electronic navigation with the simplest possible Decca Navigator. It gave you your position in lat and long, and you could enter one way point in lat and long and it would give you the bearing and distance to it.

The man machine interface was very simple, and anyone could understand it.

And all a helmsman needed to know at any time was the course to steer, and when to change it, which is what it gave. I had some demanding passages with our family needing just that.

The point is that using the goto function these days does just the same job, and better if the way points are already entered. And, with an appreciation of safe bearings to approach the way points from, is all that's needed.

The navigator/helm in the OP's story did good.

 

[prv]

I learnt my electronic navigation with the simplest possible Decca Navigator. It gave you your position in lat and long, and you could enter one way point in lat and long and it would give you the bearing and distance to it.

In terms of route setting, that’s about all I do with my very sophisticated Axiom plotter 90% of the time

It‘s not like being an aircraft pilot where everything happens so fast you’d better have the whole route pre-planned on your kneeboard. Most of us are moving not so very much above walking pace, there’s plenty of time to decide where to head next, tap it on the chart, and tap “Go To”.

Pete

 

[KompetentKrew]

I agree with the last 2 comments - I have a current model of chart plotter (and coastal skipper and just a couple of years' experience) and I just program in A, B, C, D, E waypoints - upon arrival at B, I select goto C. Nice and simple and you know where you are.

 

[EugeneR]

I remember planning my first route weeks before my first trip. I used Memory Map on my Windows Mobile handheld since the charts on the boat were not updated yet. The trip was from Port Solent to Cowes. I had about 40 waypoints down the channel to Portsmouth - maybe 10 minutes in duration - and as much again to Cowes.

On that first trip, I also learnt not to navigate "fully zoomed in". Approaching along the deep water channel to Ryde, I did the right thing and gave way to a sailing boat leaving... without realising that I was a few metres from the sandbanks. For a few seconds I could not understand why the water was minty green... until the drive kicked up hitting the sand. Fortunately, not at speed. I stopped while still floating and could reverse out a few metres, wave by wave, without any damage.

Lessons learnt.

 

[bedouin]

Thanks for the replies. My initial thought was that A to G would always be the stored route unless you reversed it "that day". Live.

Reversing the route, then turning off the MFD should to my mind have no impact on the STORED route but I do see the other argument too. Hence the ponder.

Précis .... young family, new boat, skipper with RYA Coastal, Brittany to UK, viz good, swell horrible, now hand steering, viz down to 5 miles, still "confident" ... the MFD is working and The Channel is clear, but he wanted the route. Thinks he hit reverse but it's a small symbol and the screen doesn't actually show the route flip round, now has a CTS back to where he started ... to join beginning of route G to A? or had it not reversed and it's on the original A to G ?

Being thrown around, family upset.

Lost confidence in the route so banged in GoTo waypoints, pre-Covid, not been to boat since.

Just shows the value of understanding your electronics but he had a crash course in understanding the radar, ais, vectors, trails, cpa's and so much more on just one screen he simply blanked.

My experience is also that follow route can have some odd behaviour when you are not following the route precisely. In particular deciding which WP you should be aiming for next. If you are following A-B-C and get near B deciding when to stop heading for B and switch to heading for C instead. Seeing on a CP is much more useful than blinding following a bearing to WP

I too have had the experience of asking the GPS to take me from say Portsmouth to Cherbourg only to find the route had been reversed and my first WP was the Grand Rade entrance!

 

[prv]

I agree with the last 2 comments - I have a current model of chart plotter (and coastal skipper and just a couple of years' experience) and I just program in A, B, C, D, E waypoints - upon arrival at B, I select goto C. Nice and simple and you know where you are.

To be clear, that’s not what I was describing. Perfectly valid thing to do, of course, but my normal habit is even simpler.

I rarely create waypoints in the plotter at all, unless you count the ephemeral “Cursor” one. I literally just tap the point on the chart I want to go towards right now, and go there. If it’s not utterly self-evident that there’s clear water between here and there, I’ll scrub back down the dotted line to check it doesn’t run over anything it shouldn’t. When we get vaguely near that temporary waypoint, it’s time to do something else - I rarely “arrive” at it in the way the plotter likes to announce, because I probably stuck it a little way beyond the headland or safely off the harbour mouth or whatever, and its exact position has become irrelevant now we’re in the area.

I tend to see pre-recorded waypoints as an artifact of the “numerical GPS” era, when we all had Garmin 128s. When you had to laboriously pick a position off the chart with dividers and scroll the numbers into the system one by one, of course it made sense to do that work up-front and indeed to save it for reuse in the future. But now that telling the nav system which location you‘re thinking of is as simple as touching it with a finger, I’m quite happy to just do that in real-time as needed.

Pete

 

[XDC]

when we all had Garmin 128s..

Hah ?.

Still have one at the chart table feeding position to the VHF.

Also had one as my main source of navigation on a boat I bought in '97.

 

[prv]

Still have one at the chart table feeding position to the VHF.

I still have one at the chart table for use with paper charts and a Yeoman (an older way of “just pointing at the chart“ ). Must admit I use this combination much less since getting the new plotter - mostly just for Channel crossings where I want to be following a curved track across the tides, and keeping a backup pencil plot.

Pete

 

[johnalison]

I've been using routes, on two plotters, for about twenty years. Much of or cruising has consisted of moving on each day to a new area, so setting up complicated routes is second nature, but I am often surprised by how people get themselves into a fix over them. It is not compulsory to use routes, but they make the need to spend time on navigation while on passage much less. There is nothing that would persuade me to go back to the old days of spending 3/4 hr keying in waypoints the night before a trip. My advantage is that I never grew up, and so like playing with things for hours if necessary, so learning to deal with a plotter was just play-time.

 

[James_Calvert]

Thinking again about the original question, perhaps there's a safety thing here as well?

Suppose your MFD, chart plotter, or Navigator, was turned off in the course of a passage, for whatever reason. On repowering, you'd want it to come up again with the same passage again, in the order you were using it, wouldn't you?

Not the one you might have in mind for the next day!

 

[prv]

they make the need to spend time on navigation while on passage much less.

I‘m not really trying to criticise or change anybody’s mind here - obviously everyone should do whatever works for them. But that sentence brings up two big questions for me -

1) what else are you going to do with that time?
2) how long does it take to drop in an ad-hoc waypoint anyway?

Pete

 

[johnalison]

I‘m not really trying to criticise or change anybody’s mind here - obviously everyone should do whatever works for them. But that sentence brings up two big questions for me -

1) what else are you going to do with that time?
2) how long does it take to drop in an ad-hoc waypoint anyway?

Pete

Obviously, neither of us can speak for how others sail their boats, but my way suits me. When cruising, I will usually establish a route with from four to a dozen waypoints in the evening before, or bring up a route from my list. When setting off, all I have to do is set 'follow route' and the information is displayed in the cockpit on a Graphic Repeater, with WP bearing and distance, and COG & SOG. At each waypoint, all I have to do is cancel the alarm at the repeater (which should self-cancel but doesn't always). With autopilot I need to cancel that alarm too.

It would be tiresome to have to stop helming or doing the crossword at every waypoint and create a new waypoint or fiddle around with the screen to get the cursor onto a waypoint for a new goto. A route also gives you the option, which we often use, of doing an 'advance waypoint' when you want to skip one. Sailing in the open sea can be tiring and give rise to errors. Planning a route to avoid potential hazards is part of passage-planning, and doing it in the quiet of the evening is safer for me than improvising while on the go. And my leisure time is precious too.