CD's Ponderings on ECDIS

[CharlieDelta]

This might spark an interesting debate on the use of ECDIS as a primary means of navigation.

Well, not if the culprit was uncharted. But if it was and it wasn't seen (clutter/layers turned off/distraction) then I'm sure many will be calling for some changes. I was absolutely convinced we had a great system of ENCs with radar overlay, but having thought about it now I think as OOW it would be comforting to have your paper chart, fix regularly and actually be able to see on paper what's ahead. I will, of course, bow to experience, but that's my 2p.

[alistairuk]

This might spark an interesting debate on the use of ECDIS as a primary means of navigation.

Well, not if the culprit was uncharted. But if it was and it wasn't seen (clutter/layers turned off/distraction) then I'm sure many will be calling for some changes. I was absolutely convinced we had a great system of ENCs with radar overlay, but having thought about it now I think as OOW it would be comforting to have your paper chart, fix regularly and actually be able to see on paper what's ahead. I will, of course, bow to experience, but that's my 2p.

Hitting "Standard Display" should cause all navigational hazards to be shown on the display [there was a bug with some ECDIS systems that weren't displaying correctly but these should now all have been fixed - all the manufacturers issued their mandatory updates early in 2011]

I prefer the paper charts - my opinion is that we should at least carry the small scale overview charts of areas - but although I prefer using the paper charts - ECDIS is far easier and to be honest lazier to update, with ECDIS charts you click update and it goes and downloads them - or you plug in a USB stick... it takes minutes. To do the weekly updates on a full world folio of BA charts takes between 4 and 8 hours per week but my rants about chart corrections is a different matter!

Technology should be embraced - knowing the limitations of your system is always worthwhile and relying on GPS/DGPS and ECDIS as your position fixing method when in coastal waters is just stupid - as a very least use PI's!

[CharlieDelta]

Hitting "Standard Display" should cause all navigational hazards to be shown on the display [there was a bug with some ECDIS systems that weren't displaying correctly but these should now all have been fixed - all the manufacturers issued their mandatory updates early in 2011]

I was told to avoid Std Display, apparently on ours it removed "other seabed features". Unless that's the bug.

Technology should be embraced - knowing the limitations of your system is always worthwhile and relying on GPS/DGPS and ECDIS as your position fixing method when in coastal waters is just stupid - as a very least use PI's!

You're right, I suppose there's so many advantages. Silly question though, and one that I should really have asked at sea, but is it possible to plot "manual" fixes on ECDIS? Say I take some visual bearings, can I plot them to compare with the GPS position?

[alistairuk]

You're right, I suppose there's so many advantages. Silly question though, and one that I should really have asked at sea, but is it possible to plot "manual" fixes on ECDIS? Say I take some visual bearings, can I plot them to compare with the GPS position?

Sam Electronics NACOS allows you too, but its a pain in the arse - basically you have to key in a manual Lat / Long and time taken - although it can calculate LOPs from Celestial fixes for you.

You can do radar ranges and bearings using the radar overlay on some radars as well and fed it into the ECDIS automatically but since its basically plotting the fix on the ecdis using the ecdis I don't really see any point in doing it - since if your charts in the wrong position (i.e.: GPS is buggered and doesn't know its buggered - chart automatically turns off on your radars if the GPS feed is unreliable), your fix is going to be wrong too

[CharlieDelta]

Just done some Googling on the subject, I see what you mean. So if you lose your GPS there's effectively no way to plot a fix if you don't have paper charts available? If the ECDIS expects a Lat/Long and you've just got radar ranges/bearings or visual bearings how are you meant to convert them to lat/long with no paper chart?

Oops, we're wandering, might set up a separate "CD's ponderings on ECDIS" thread.

[alistairuk]

Just done some Googling on the subject, I see what you mean. So if you lose your GPS there's effectively no way to plot a fix if you don't have paper charts available? If the ECDIS expects a Lat/Long and you've just got radar ranges/bearings or visual bearings how are you meant to convert them to lat/long with no paper chart?

Oops, we're wandering, might set up a separate "CD's ponderings on ECDIS" thread.

You don't... hence why in order to have purely ECDIS with no paper charts you need to completely independent systems with their own independent inputs... You'll also have 2 or 3 different GPS feeds into your main ECDIS anyway, so if 1 dies you can switch to the other.

But yer, if you have to do manual fixing onto an ECDIS without a position, it becomes a pain in the ass - not impossible to do... you could always take your range and bearings on the radars... goto the main ECDIS display, and use the "draw line" tool to essentially do what you would do on a paper chart... then get the position that way.

I'll let you move them... cause I don't know what forum to stick em in!

[gadget123]

I'm pretty sure all ECDIS's have to have the facility to manually fix a position.
However how easy it is to use depends on the system your using. I know it is pretty easy to do on the Transsas system, just enter the range and/or bearing and click on whichever bit of land, light, beacon etc when as you enter more position lines it does decides where you are and puts a fix on the chart with a time next to it.

[alistairuk]

I'm pretty sure all ECDIS's have to have the facility to manually fix a position.
However how easy it is to use depends on the system your using. I know it is pretty easy to do on the Transsas system, just enter the range and/or bearing and click on whichever bit of land, light, beacon etc when as you enter more position lines it does decides where you are and puts a fix on the chart with a time next to it.

TRANSAS has many nice little (read: easy to use and actually useful) features - including as you say the ability to set ranges and bearings out of chart objects. Alas it is one of the few that does this - most (Including Sam's NACOS - as far as I am aware - certainly the version we have onboard anyway) only allow inputs of Lat / Long as manual fixing.

The other nice feature of TRANSAS is you can hover the cursor over a waypoint and it gives you ETA information! Why don't they all do that!

Going back to CDs original statement... of other means of fixing if you only had ECDIS onboard... Don't forget a very big clue that your not where you are meant to be is the ECHO SOUNDER - if you start getting unexpected readings of < 100m in the Med... theres a good chance your going to hit something since most of it is very deep!

PI's being the easiest - set them up in advance of the alteration! or if your doing coastal scenic cruising VRMs set at whatever minimum distance you want to maintain, and then set another at the absolute minimum before you crash!

Also take into account "watch keeping" implies looking out the window - if you can see people sunbathing on a beach and your meant to be 12 miles away - somethings wrong!

[CharlieDelta]

The other nice feature of TRANSAS is you can hover the cursor over a waypoint and it gives you ETA information! Why don't they all do that!

Can do this with NACOS too can't you? Or at least put cursor anywhere and get TTG info? For noon speech position I just ran the cursor along the track and when it gave me an ETA of 1200 read off the position.

[YoungMariner]

CD, Yes. But the benefit of being able to select a WP is that it gives you an accurate ETA along your course, for instance if your on a longer passage or one that involves several alterations of course where a simple cursor over the position woudn't work.

[ETwhat?]

I've always found Transas to suffer from the problem of you can zoom in to see the detail but then not where your going or you can zoom out to see whats infront of you but not the detail of where you are, I guess the ideal would be a screen the size of a standard admiralty chart.

with a radar overlay its fairly easy to see if the gps is giving wrong data as the digital chart wouldnt be under the returns, If CD believes he would feel safer using a paper chart it becomes much harder to check that the GPS is still correct without having to go look through the windows. it does come down to how much you trust the technology and how well you can use it

[CharlieDelta]

I've always found Transas to suffer from the problem of you can zoom in to see the detail but then not where your going or you can zoom out to see whats infront of you but not the detail of where you are, I guess the ideal would be a screen the size of a standard admiralty chart.

The current incarnation of the Transas ECDIS allows dual display, so you can have one small scale and one large scale.

If CD believes he would feel safer using a paper chart it becomes much harder to check that the GPS is still correct without having to go look through the windows. it does come down to how much you trust the technology and how well you can use it

Looking through the windows is a big part of the job...

Seriously though, I'm all for ECDIS and as a cruise ship cadet I like to think that our training equips us very well - we are the electronic navigators and I'm happy to be here during a huge change in the way navigation is conducted. But I think there's still a place for the paper chart on the modern bridge.

[ETwhat?]

the point about looking through windows was more about how you gain and prove the information that your then plotting onto a paper chart.

[CharlieDelta]

I get that, but even with a fully ECDIS ship, looking through the windows in coastal waters is good practice to crosscheck your position anyway.

[gadget123]

Obviously you need to look out of the windows regardless of how you are navigating, GPS can be wrong radar can have errors you can never trust any of them completely.

One thing I think is quite interesting is how many things on the bridge of a ship is reliant on a GPS signal. I was on a ship where the captain managed to unplug the main GPS (we were about a thousand miles from land so it wasn't a major problem) but it was amazing how many alarms went off because of it.