Navionics AIS

[Yealm]

The annoying two nag screens in Navionics have worked and I’ve relented and paid their annual license tax for iPhone (surely the most expensive app?!) - grrrrrr…

But noticed they now have AIS integration over WiFi.

Has anyone used this ? Wondered if any good?

 

[CPD]

Used yes, and yes it is good .

 

[MoodySabre]

I have AIS by Wi-Fi via a Yakker. Very good.

 

[fredrussell]

There’s a good thread about it on YBW somewhere.

 

[alexincornwall]

I've used this feature extensively over the past twelve months and I think there is a serious issue which I posted on another forum some time ago.

I’m fairly certain there is a problem where the current version of Navionics displays an error in the CPA of a target (class A and B ), suggesting it is between 2-5 cables further away than it really is. This then completely throws the TCPA.

I noticed this on a channel crossing last summer where my Vesper transponder was supplying hardwired data to my chart plotter, with wireless data to it’s own WatchMate app and the Navionics app (same device).

I had a target showing on Navionics with a range of 3.5 cables, both of the other devices showing 0.5 cables. Visually, it was 100% less than 3.5 cables and this has happened multiple times since. Conveniently had a friend who was crossing a couple of boat lengths away using a non vesper transponder confirm the same error. There is no issue with the GPS fix because both devices and both Navionics and Watchmate had us in exactly the same position.

Of course I wouldn't be completely reliant on AIS data full stop but I definitely wouldn't trust Navionics for AIS after that. Maybe I'm wrong but I reckon there is an algorithm issue with Navionics calculations...

 

[MoodySabre]

I also have AIS on my SH VHF so will check TCPA with that when I next go near any targets (not any time soon). Thanks for that comment @alexincornwall

 

[jamie N]

I'm not trying to be silly, but using "cables" isn't relevant to any 'real World' chart is it, or am I missing something?
Alexincornwall, please don't take this in any way as a criticism towards yourself, but in 48 years offshore, and all of my life as a sailor, I've never found anything sensible in it, or having it referred to ever, above metric; it's a one dimensional measurement.
Navionics don't include it as part of my settings, and I wouldn't be as comfortable using it in place of metric.

 

[bitbaltic]

I'm not trying to be silly, but using "cables" isn't relevant to any 'real World' chart is it, or am I missing something?
Alexincornwall, please don't take this in any way as a criticism towards yourself, but in 48 years offshore, and all of my life as a sailor, I've never found anything sensible in it, or having it referred to ever, above metric; it's a one dimensional measurement.
Navionics don't include it as part of my settings, and I wouldn't be as comfortable using it in place of metric.
View attachment 130234

It’s 1/10 of a Nm so it’s in your settings right there, isn’t it?

 

[jamie N]

Yes, but why use it when it requires a separate 'calculation' from what's displayed? My horizontal distance is in metres; my depth is in metres. Are there any charts that refer to cables? It's an irrelevant and archaic standard clinging to a long gone era, I'd suggest.

 

[bitbaltic]

Your horizontal distance appears to be in nautical miles (1852 metres). Not sure how you think you’re working in metres.
quick scan of 2022 Reeds reveals endless references to cables. Not bothered to get the chart packs out but I’m sure I’ll find references. I’ll likely also find axes/scales marked in cables.

it’s never occurred to me to be a source of controversy.

 

[alexincornwall]

I'm not trying to be silly, but using "cables" isn't relevant to any 'real World' chart is it, or am I missing something?
Alexincornwall, please don't take this in any way as a criticism towards yourself, but in 48 years offshore, and all of my life as a sailor, I've never found anything sensible in it, or having it referred to ever, above metric; it's a one dimensional measurement.
Navionics don't include it as part of my settings, and I wouldn't be as comfortable using it in place of metric.
View attachment 130234

No offense taken whatsoever, but that's a most peculiar comment from an experienced offshore sailor. 60NM = 1 degree latitude. 1NM = 1 minute. 1NM = 10 cables. 1NM = 1852 meters, 1 cable = 185M. So when you set your Navionics to NM you're selecting nautical miles and cables. If Navionics says your CPA (for example), is 0.3NM, that's 3 cables. Measuring in any other format would be crazy.

 

[Rappey]

I've never seen "cables" on any electronic device. Instead they would show something like 0.35miles .
I'm aware of a cable but didn't know how long one was , so I did google it and learnt it's also 100 fathoms which is another measurement that does not help me when charted depths are in metres.
A cable can also be anything from 169 metres to 220 metres depending on the standard used according to wikipedia. Not sure how that works as I did not read it .
I wouldn't say it's a source of controversy, maybe more a generation thing where the youtube generation navigate the globe electronically whereas the longer time served older sailor would be able to show some detailed paper chart work and would likely be familiar with many more nautical terms

 

[jamie N]

Your horizontal distance appears to be in nautical miles (1852 metres). Not sure how you think you’re working in metres.

You're quite right, but (amongst others), I do judge my 'yottie' nav in Nm's, in my defence, every other measurement on my boat is in metres with visible distance, and speed in knots as I'm familiar with the 'concept' of it.

No offense taken whatsoever, but that's a most peculiar comment from an experienced offshore sailor. 60NM = 1 degree latitude. 1NM = 1 minute. 1NM = 10 cables. 1NM = 1852 meters, 1 cable = 185M. So when you set your Navionics to NM you're selecting nautical miles and cables. If Navionics says your CPA (for example), is 0.3NM, that's 3 cables. Measuring in any other format would be crazy.

It's perhaps a turn of phrase, in that I've never used cables as a measure of distance, as metres appear to me far more readily.
However, your explanation does explain the correlation, and I thank you for it.

 

[Yealm]

Interesting, is the cable the only example of a decimal being used in a non-SI system?
I've never heard anyone say cable in the real world - not sure it' really a useful unit - if you're going that small for distance, I'd use meters (eg 100m an easily relatable sprint distance).

 

[alexincornwall]

I'm surprised. As far as I was aware, nautical distances are only measured in nautical miles or cables in the same way that nautical speeds are measured in knots and depths are measured in fathoms (although the latter is a bit obsolete these days).

Any RYA training would be delivered using Nm and cables, paper charts use cables in their latitude scale, most almanacs and pilot books would use Nm and cables, and if you were to converse with a commercial vessel by VHF for collision avoidance, they would use Nm and cables universally.

Obviously a degree of sensibility comes into play. If something was 50 meters away, I'd say it was 50 meters away and if somebody asked me where the local shop was, I wouldn't say it was 2 cables down the road on the left!

Navionics or any other plotting device might not display the term in writing, but by selecting distances in Nm, you would have also defined a cable for each tenth of a mile.

 

[[3889]]

Interesting, is the cable the only example of a decimal being used in a non-SI system?
I've never heard anyone say cable in the real world - not sure it' really a useful unit - if you're going that small for distance, I'd use meters (eg 100m an easily relatable sprint distance).

I frequently refer to SOG as 54 cables an hour (or whatever), partly because it sounds impressive and partly to bemuse shipmates. Puerile, I know.

 

[Yealm]

I frequently refer to SOG as 54 cables an hour (or whatever), partly because it sounds impressive and partly to bemuse shipmates. Puerile, I know.

Not at all, I think an entirely appropriate (and probably only) reason to use cables !

 

[alexincornwall]

I frequently refer to SOG as 54 cables an hour (or whatever), partly because it sounds impressive and partly to bemuse shipmates. Puerile, I know.

10,001 metres an hour. That’s really fast!

 

[[2574]]

Surely this is purely very useful nomenclature? To say “a tenth of a mile” is potentially confusing because the recipient might be unsure whether the mile unit being used is Statute mile or Nautical mile. To say “a cable” avoids confusion. Same applies to KW vs KVA, two similar measures but with different meanings that shouldn’t be confused. I use the “cable vernacular” at sea.

 

[CM74]

Yes, but why use it when it requires a separate 'calculation' from what's displayed? My horizontal distance is in metres; my depth is in metres. Are there any charts that refer to cables? It's an irrelevant and archaic standard clinging to a long gone era, I'd suggest.

All charts use cables - it's 1/10 of a nautical mile so also 1/10 of a minute of latitude so it's very easy to measure and plot on any chart. The scale bar will also have cables on it.
Pilot books refer to cables, and commercial systems give ranges as eg. 0.4NM so 4 cables.

Sounds archaic and quaint but it has a real practical purpose and works well!