A chart plotter with audible alerts?

[BeginnerBoater]

Originally Posted by Flatswing

A) as others have stated clearly, virtually all chart plotters have simple visual (colorimetric) depth warnings, most have audible depth alarms
B) even rudimentary depth finders like the Hawkeye on my dinghy have audible alarms. But many of us turn them off as they are distracting in critical nav environments.

Gotta say though that if glancing at the chart plotter from time to time is too inconvenient for you, well -you know.

I'm not saying I wouldn't be willing to check the C/P every now and then. All I want is that I don't need to stare at it too much. As a beginner, "a glance" may not be enough but I'd need to look a bit longer time to verify the situation. Therefore I'd rather save those moments to the cases where the attention is especially needed, and let the C/P we my watchdog when there's nothing worth checking.

The whole opening post is based on the rumor that I heard ("C/P don't give audible warnings") and that has been shown to be a false claim.

[sv_pelagia]

My older Furuno chartplotter with CMAP does have a "safe route" checking option.

I've turned it OFF as it would always find shallows/rocks ahead on my current course, ones which I see on the chart and fully intend to avoid.

But the chartplotter can't seem to read my mind....

[BeginnerBoater]

Originally Posted by sv_pelagia

My older Furuno chartplotter with CMAP does have a "safe route" checking option.

I've turned it OFF as it would always find shallows/rocks ahead on my current course, ones which I see on the chart and fully intend to avoid.

But the chartplotter can't seem to read my mind....

Oh... I see. If your route has shallows/rocks all the time so that you need to look at the chart every couple of seconds, I understand you don't have use for audible warnings. In my case, I expect to have such a warning maybe once per 10 mins or even once per 30 mins. That's why I'd like to get audible warnings.

[Stu Jackson]

Originally Posted by BeginnerBoater

Oh... I see. If your route has shallows/rocks all the time so that you need to look at the chart every couple of seconds, I understand you don't have use for audible warnings. In my case, I expect to have such a warning maybe once per 10 mins or even once per 30 mins. That's why I'd like to get audible warnings.

I think I understand your "issue(s)." You've been pretty clear.


Perhaps we could approach this in a different manner.


For starters, perhaps you have been looking at this backwards, from experiences with automobile GPSs and their verbal warnings.


Now, look back only a single generation, to, like, me! I'm a mere 75, and started, like you did, lake sailing. No charts, not even paper ones. We soon developed what folks still call local knowledge, no one wrote anything down, but we all knew that SW of Elephant Rock was a shallow bar, and we learned to avoid it.


Fast forward to the early 1980s, when I bought my first sailboat on SF Bay. They hadn't invented chartplotters, GPS was still way off, and all I had were, gasp!, paper charts.


Which I LOOKED AT!



Then I got a West Marine Loran which only displayed lat/lon, no charts! Gasp! So I had to learn lat/lon transfers to the paper chart to determine where I was.


So I LOOKED AT the charts.


Then came GPS, still only lat/lon.


So I LOOKED AT the charts.


Then came GPS WITH charts.


So I LOOKED AT the charts ON THE GPS, as well as the paper charts which I also always had with me.


Are you seeing (sorry, pun intended) a PATTERN here?


Two things:


1. If you sail locally enough, you WILL learn your LOCAL waters and underwater obstructions because you will become familiar with them. Like driving to your local 7-11, you don't need a map, but most likely have one in your car.


2. As you expand your sailing grounds to NEW places, you will REQUIRE charts as part of prudent seamanship. In order to determine how to SAFELY get from A to B, you will have to LOOK AT the charts.


Are you seeing the pattern here?


Good luck, but luck should have nothing to do with it.

[Be Free]

Originally Posted by requiem

Your list of assumptions is good, but it left out the position accuracy of the soundings, which for zone of confidence A2 would be ±20 m.

Still, such a look-ahead feature can be found in fancier navigation packages. For example, take a look at the "security cone" or "route planning" screenshots for TZ Navigator: https://mytimezero.com/tz-navigator.

Personally I think it would be a useful safety net, but also one that generally shouldn't be triggered if one is properly paying attention (false alarms excepted, as any course that winds between shallows would trigger them).

I'm not sure that even this software would address all of the OP's requirements particularly that it run on a phone and not use external depth sensors. At $500 it's not much less than a dedicated chart plotter.


My old Garmin 700 series chart plotter does a pretty good job of looking ahead for waypoints and land and it can alert at any depth I set it for but it can't predict low water ahead without a transducer.

[BeginnerBoater]

Originally Posted by Stu Jackson

I think I understand your "issue(s)." You've been pretty clear.


Perhaps we could approach this in a different manner.


For starters, perhaps you have been looking at this backwards, from experiences with automobile GPSs and their verbal warnings.


Now, look back only a single generation, to, like, me! I'm a mere 75, and started, like you did, lake sailing. No charts, not even paper ones. We soon developed what folks still call local knowledge, no one wrote anything down, but we all knew that SW of Elephant Rock was a shallow bar, and we learned to avoid it.


Fast forward to the early 1980s, when I bought my first sailboat on SF Bay. They hadn't invented chartplotters, GPS was still way off, and all I had were, gasp!, paper charts.


Which I LOOKED AT!



Then I got a West Marine Loran which only displayed lat/lon, no charts! Gasp! So I had to learn lat/lon transfers to the paper chart to determine where I was.


So I LOOKED AT the charts.


Then came GPS, still only lat/lon.


So I LOOKED AT the charts.


Then came GPS WITH charts.


So I LOOKED AT the charts ON THE GPS, as well as the paper charts which I also always had with me.


Are you seeing (sorry, pun intended) a PATTERN here?


Two things:


1. If you sail locally enough, you WILL learn your LOCAL waters and underwater obstructions because you will become familiar with them. Like driving to your local 7-11, you don't need a map, but most likely have one in your car.


2. As you expand your sailing grounds to NEW places, you will REQUIRE charts as part of prudent seamanship. In order to determine how to SAFELY get from A to B, you will have to LOOK AT the charts.


Are you seeing the pattern here?


Good luck, but luck should have nothing to do with it.

Thank you for the interesting story. A piece of history!

But one thing about looking at charts is a bit unclear to me: Does the image on the C/P screen give me some useful information that can't be given by voice?

[Be Free]

+1 on local knowledge. I'm not quite as old as Stu but I remember one island I liked to camp on that was about a quarter mile from the boat ramp. The only problem there was a sand bar there that had less than 1 foot of water over it at low tide. That meant a several mile detour around another island to get to the camping spot.


However, if you ran straight at the sand bar with your boat on a plane and did not slow down for any reason you could clear it. Kinda like Peter stepping out of the boat. You had to have faith (and some local knowledge)

[BeginnerBoater]

Originally Posted by Be Free

+1 on local knowledge. I'm not quite as old as Stu but I remember one island I liked to camp on that was about a quarter mile from the boat ramp. The only problem there was a sand bar there that had less than 1 foot of water over it at low tide. That meant a several mile detour around another island to get to the camping spot.


However, if you ran straight at the sand bar with your boat on a plane and did not slow down for any reason you could clear it. Kinda like Peter stepping out of the boat. You had to have faith (and some local knowledge)

+2 to local knowledge. In my case, I won't have regular journeys on the same waters, but the lakes will be more or less new to me all the time. So, I lack local knowledge. From the locals I can hear if there are plenty of rocks in the specific lake or not, but if there are only few, I'd like to deploy modern technology to assist me not to hit them and yet give me maximum freedom to enjoy the lake view.

[karle]

Originally Posted by BeginnerBoater

The navigators (used in land traffic) have offered audio warnings since the very beginning, around 20 years. How is it with plotters, are there any that gives audio alerts? I mean, if you are heading towards shallows, it would alarm the boat driver. Technically that feature is a peanut to make. I have absolutely minimal experience with chart plotters, do they give even visual alerts?

Which audible alert are you referring to?
All of these exist in one form or the other.

• Safety/ Shallow Depth Alarm
• AIS collision alarm
• Anchor breach alarm
• Cross track error alert
• Waypoint arrival alert
• Off route alert
• Low tide when you arrive alert
• Detected fish under sounder alert
• Custom alert created using a combination of NMEA sensor data (low fuel etc)

[BeginnerBoater]

Originally Posted by karle

Which audible alert are you referring to?
All of these exist in one form or the other.

• Safety/ Shallow Depth Alarm
• AIS collision alarm
• Anchor breach alarm
• Cross track error alert
• Waypoint arrival alert
• Off route alert
• Low tide when you arrive alert
• Detected fish under sounder alert
• Custom alert created using a combination of NMEA sensor data (low fuel etc)

Thanks! That's actually what I wish to hear, but I had earlier heard (false information - or "fake news" as some former statesman used to say...) that chart plotters don't give audio warnings.

[CarinaPDX]

In my experience the chartplotter alarms using internal buzzers are not nearly loud enough to be heard reliably over the ambient noise. Fortunately it is sometimes possible to add an external buzzer. Furuno chartplotters have connections for external buzzers, and I have rigged one with a defeat switch. It is a cheap and easy upgrade.

That said, while I often use alarms as a backup I try never to rely on them. The exception is the anchor alarm since I don't stand an anchor watch in benign conditions, but in that case I usually set both depth and position alarms. Still, the point is that you should maintain awareness such that alarms are not needed, or relied upon (and always anchor like you expect a squall). Make frequently referring to the chart and position a habit, at least if you plan on expanding beyond your own lake.

Greg

[requiem]

Originally Posted by BeginnerBoater

In case of suddenly lowering dept, the transducer may give an alert too late.

This bit is worth mentioning again; depth alarms only work if you have a nice gradual change. Being able to define and mark you own exclusion zones can help with this, but even that is usually based on distance rather than time.

Originally Posted by BeginnerBoater

But one thing about looking at charts is a bit unclear to me: Does the image on the C/P screen give me some useful information that can't be given by voice?

There's an old saying about what a picture is worth. But, with electronic charts there are some features to be aware of. First is the safety depth & safety contour (some nav apps conflate the two). If you set these appropriate to your boat it will make it much easier to detect hazards at a glance, as the go/no-go areas will be distinguished by color.

This isn't always perfect; since the contours end up picking the "safest" available you might set a 2 m safety contour and the next deepest the chart has is 4m. It's also common for soundings to also change shade, e.g. safe values in gray and unsafe ones in black, to help you visually pick out safer areas should you need to cross the safety contour.

[requiem]

Originally Posted by Be Free

My old Garmin 700 series chart plotter does a pretty good job of looking ahead for waypoints and land and it can alert at any depth I set it for but it can't predict low water ahead without a transducer.

How does your Garmin alert for land? Not to get into semantics, but an alert for land sounds awfully similar to what OP was interested in, particularly if "land" can be defined by a user-configurable depth.

[MJH]

Originally Posted by BeginnerBoater

The navigators (used in land traffic) have offered audio warnings since the very beginning, around 20 years. How is it with plotters, are there any that gives audio alerts? I mean, if you are heading towards shallows, it would alarm the boat driver. Technically that feature is a peanut to make. I have absolutely minimal experience with chart plotters, do they give even visual alerts?

If you have "total" Local Knowledge you don't need a chartplotter.

When you go outside your local area (whatever you claim that to be) your first task is to look at the charts and construct your route, obviously to avoid the shallows and obstructions. You could then connect your chartplotter to your autopilot and let it track that route while enjoying the view. I wouldn't do that but it sounds that is what you are looking for.

Please stay on your lake.

~ ~ _/) ~ ~ MJH

[BeginnerBoater]

Originally Posted by waterman46

Beginner, when you gain more experience, perhaps running aground a few times, you will see that your attitude may change.

There is always a "specific reason" to look at a chart at reasonable intervals whether or not you sense any danger. The specific reason is, you are piloting a boat.

But I do see the logic in your suggestion, since none of us are perfect and we sometimes neglect to pay attention. And I don't think it's unreasonable to question whether such a warning function could be programmed into chartplotters.

The thing I was looking after here, is whether the chartplotters have an audible warning function or not. And now I have heard that they do have, at least some of them.

For what reason I should look at the chartplotter even in the cases there are no shallows/rocks in front (but just deep water)?