A chart plotter with audible alerts?

[BeginnerBoater]

Originally Posted by MJH

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

Why should I check the shallows/rocks in advance (before starting my journey), why can't I handle them once they appear in my way? They will be very rare anyway. In a similar fashion like my car navi warns about speed cameras: I never check the speed camera locations in advance but I react to my navigator's audio warnings. [I'm not saying that I use to speed, but in my country we have pretty expensive speeding fines, and at camera locations we use to pay extra attention to the speedometer.]

[ranger58sb]

Originally Posted by 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.

All of our alarms were easily loud enough to hear... and we also had ambient engine noise the alarms had to overcome. No issues, even without external buzzers. That's with electronics mounted at the helm.

It may differ a lot for installations where the plotter (etc.) is located below, perhaps at a chart table. (Much like trying to raise a boat on VHF when it's mounted below decks somewhere.) I could see in those instances where external buzzers could be a great solution.

-Chris

[MJH]

Originally Posted by BeginnerBoater

Why should I check the shallows/rocks in advance (before starting my journey), why can't I handle them once they appear in my way? They will be very rare anyway. In a similar fashion like my car navi warns about speed cameras: I never check the speed camera locations in advance but I react to my navigator's audio warnings. [I'm not saying that I use to speed, but in my country we have pretty expensive speeding fines, and at camera locations we use to pay extra attention to the speedometer.]

There are always limitations in making an analogy as you do comparing a vehicle speed warning device to depth and obstruction devices with the inherent and very different possible outcomes.

Lastly, the automotive industry is much larger than the recreational boating industry and there is more financial incentive to produce electronics for them than for recreational boats.

~ ~ _/) ~ ~ MJH

[waterman46]

Originally Posted by BeginnerBoater

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?

A picture is worth 1000 words. Or more in most cases.

Actually I like the idea of an alarm sounding if the projected course encounters less than a user-defined depth limit within the user-defined time, and would probably use it carefully much of the time.

Think of it as a backup - exactly the same as all your other instruments. I hope nobody out there is sailing around depending on only instruments and no visual or audible clues! But we all welcome inputs from any instruments that can help reduce danger, fatigue and increase accuracy.

You use AIS to alert you of CPA: it's exactly the same idea. You are keeping a visual lookout, but the AIS may detect a problem before you can see it visually. Radar, depthsounders, your crew, all are there to help you but you never depend absolutely on any one of them.

[Stu Jackson]

Originally Posted by BeginnerBoater

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?

Ach, I've been waiting three quarter centuries to say, "Hey, you young whippersnapper, get off my lawn!"

I've been thinking about this for the past few days. The answer to paragraph 2 about voice:


When you're in a car, the GPS and voice know which way you're going, what's up ahead on the highway, and your destination. Three basic things.

On the water, you can literally go in 360 at any time. There is no road.


One could "argue" that setting a "route" on a marine GPS is a road, and that the GPS voice should warn you if you are about to encounter a hazard.

Originally Posted by BeginnerBoater

Why should I check the shallows/rocks in advance (before starting my journey), why can't I handle them once they appear in my way? They will be very rare anyway. In a similar fashion like my car navi warns about speed cameras: I never check the speed camera locations in advance but I react to my navigator's audio warnings. [I'm not saying that I use to speed, but in my country we have pretty expensive speeding fines, and at camera locations we use to pay extra attention to the speedometer.]

I was seriously taken aback by the first sentence in this nonsense.

Again, this thinking is bassackwards, because in developing the route, a prudent mariner will NOTICE these hazards and work the course of the segments of the route to avoid them. Thus negating the entire necessity of voice warnings.


PS " In my country" people can actually obey the laws, drive within the speed limit, and do it all without a voice telling him to watch out for devices that are developed to catch him breaking the law. Geez, what a country.

[waterman46]

Originally Posted by Stu Jackson

Ach, I've been waiting three quarter centuries to say, "Hey, you young whippersnapper, get off my lawn!"

I've been thinking about this for the past few days. The answer to paragraph 2 about voice:


When you're in a car, the GPS and voice know which way you're going, what's up ahead on the highway, and your destination. Three basic things.

On the water, you can literally go in 360 at any time. There is no road.


One could "argue" that setting a "route" on a marine GPS is a road, and that the GPS voice should warn you if you are about to encounter a hazard.




I was seriously taken aback by the first sentence in this nonsense.

Again, this thinking is bassackwards, because in developing the route, a prudent mariner will NOTICE these hazards and work the course of the segments of the route to avoid them. Thus negating the entire necessity of voice warnings.


PS " In my country" people can actually obey the laws, drive within the speed limit, and do it all without a voice telling him to watch out for devices that are developed to catch him breaking the law. Geez, what a country.

I'm sure we are all prudent mariners, but which of us is perfect and could not use any help more than all our other instruments provide? I'm not ashamed to admit I have at least once encountered (safely) a navigational hazard that was on the chart at a high zoom level but which I didn't see during my route planning. I think the OP's question and proposal, if it was that, has considerable merit.

As I posted earlier, such an early warning device can be used or not, it's up to you, but it could be a valuable addition to our bag of navigation tools. It also crossed my mind that, unlike depthsounder, radar or an AIS transmitter, if you are using your chartplotter anyway then an audible warning would be nearly "free" in terms of power usage.


Such a feature would be valuable when sailing single-handed and using wind angle with autopilot. In this case you cannot use cross-track errors since your course is not pre-determined to an exact location. A depthsounder can tell you if you have strayed into shallow water, but by then it may be too late.

[Be Free]

Originally Posted by requiem

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.

My bad. I was conflating OpenCPN alarms with my Garmin alarms. I use the Watchdog plugin and the Landfall alert.
I don't think he was specifically interested in a "land" alarm as much as a shallow water or underwater obstruction alarm. The Garmin can certainly be configured to alarm at any user configurable depth but he wanted something that would work without a transducer.

[Be Free]

Originally Posted by BeginnerBoater

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)?

You look at the chartplotter to see IF there are shallows/rocks in front that are not readily apparent by looking at the water.


You look at it for the same reason you want it to give you an audible alert: to let you know there is something ahead that may need your attention.

[dgmultimedia]

https://buy.garmin.com/en-GB/GB/p/567680#additional

[requiem]

Originally Posted by Be Free

I was conflating OpenCPN alarms with my Garmin alarms. I use the Watchdog plugin and the Landfall alert.

I was looking at the Draw plugin and it seems using that and Watchdog to draw exclusion zones around hazards would get close to what the OP was looking for. (At least for moving at common sailing speeds.)

[dgmultimedia]

Originally Posted by dgmultimedia

https://buy.garmin.com/en-GB/GB/p/567680#additional

Forward facing sonar transducer into Garmin chart plotter - DONE!

[Be Free]

Originally Posted by requiem

I was looking at the Draw plugin and it seems using that and Watchdog to draw exclusion zones around hazards would get close to what the OP was looking for. (At least for moving at common sailing speeds.)

I've done that too with charts created from Google Earth on some local lakes. It works great but it does take some time to work on the chart and set up the software beforehand.

[OS2Dude]

Every chartplotter I'm aware of has the ability to set a depth alarm. On ours I set it to 12' (Our boat draws 5.5') so I have some warning of shallowing bottoms while I still have some time. A forward looking sounder gives you a look at the slope of the bottom 8 times the depth of the water. I have no direct experience with these devices, but that seems to do what you are looking for.

[Shrew]

Originally Posted by BeginnerBoater

Why should I check the shallows/rocks in advance (before starting my journey), why can't I handle them once they appear in my way? They will be very rare anyway. In a similar fashion like my car navi warns about speed cameras: I never check the speed camera locations in advance but I react to my navigator's audio warnings. [I'm not saying that I use to speed, but in my country we have pretty expensive speeding fines, and at camera locations we use to pay extra attention to the speedometer.]

[swordds]

I sail singlehanded on an inland estuary using Navionics on my iPhone. I often sail at night so having the phone in the cockpit with the glare from the screen so I can watch the chart is not a great option. There are a few fixed but unlighted obstructions in my sailing area that are very difficult and sometimes almost impossible to see at night. Being able to set an audible alarm parameter around those obstructions would be a great comfort. I have emailed Navonics about the possibility of adding this feature but to no avail.