Radar is now redundant ?

[Bycrick]

How wonderful! An autonomous boat. I can spend lots of work and money maintaining it, then sit in the bar and drink while it goes sailing. It will probably have real-time comunication so I’ll be able to tell the bar boys stories without ever getting wet or sunburned. The video feed gets sent direct to a YouTube. I can hardly wait.

[Cadence]

Originally Posted by Bycrick

How wonderful! An autonomous boat. I can spend lots of work and money maintaining it, then sit in the bar and drink while it goes sailing. It will probably have real-time comunication so I’ll be able to tell the bar boys stories without ever getting wet or sunburned. The video feed gets sent direct to a YouTube. I can hardly wait.

In an autonomous boat we could hire the bar boy.
Drift?

[Scorpius]

Originally Posted by Cadence

I can't imagine what is going to happen when the electrics take a dump on someone, although I think that is here today. I'm old and crochety but hope the people reliant on their electronic know how to get home.
The horse and buggy days were exhilarating.

[GrowleyMonster]

Originally Posted by Bunnellr

My experience with radar is that the information is so unreliable, it is useless. Good AIS is much better. If you count on radar, you are counting on bad info. I would have removed it, except some folks think it is useful, so a sale item.

I hate to tell you this but your experience is flawed. If you take the time to learn to operate and observe your radar correctly, and understand radar's limitations and strengths, it is extremely reliable. Ships all have a 3cm and a 10cm radar and this has been so since at least the 80's. Supply boats, crew boats, offshore tugs, all have radar and have had radar for a very long time. Shrimp boats have had radar since back in LORAN A days. If radar was unreliable or useless, would all these vessels have it? There is no legal requirement for an uninspected fishing vessel to have radar, but they have it and have had it for over 50 years. Why clutter the wheelhouse with another great big piece of equipment, and pay thousands of dollars, for something that is useless? Just reading the threads in this post should have you questioning not radar's usefulness, but your skill in using it.

If you don't want radar on your boat, fine. Your boat, your business. There is no need to defend your decision. But if you spout misinformation such as radar is useless and unreliable, someone is of course going to offer rebuttal. You are simply wrong. It is not "better" than AIS, nor is AIS "better" than radar. Apples and oranges. If you don't like apples, just eat the oranges and never mind the apples.

[requiem]

Originally Posted by Kelkara

I have a simple technical question ... if CHIRP measures a change in frequency to calculate distance, and the doppler effect measures a change in frequency to calculate movement ... how is it possible to combine both in the same unit?

You might find this helpful: https://www.radartutorial.eu/02.basi...0Radar.en.html

But in short, if you imagine two measurements on an object, one on a rising and the second on a falling frequency, then you can easily identify the Doppler component.

[AlanR]

"A radar overlay shows you very clearly how far the GPS is off on that specific chart"

It is the chart that is in error, not the GPS or the radar signal.

[gmowbray]

The question was “is radar redundant” and if redundant means “no longer useful” then the answer is clearly no. Is radar as valuable as it once was now that we have chartplotters and GIS and AIS then the answer is no it is not as valuable as it was say 20 30years ago. Does radar still serve a purpose and give useful information - yes. I used to work in IT where “redundant” is used to mean a backup or failover system and in that context I would say radar is redundant in that it provides backup and surety over the other sources of nav data. Would you dump your charts because a chart plotter has them stored internally? I doubt it even though in some cases the charts are way out of date. All sources of nav data working together give richness to the nav data that keeps us safe.

[Dieseldude]

Been reading the posts of arguments for and against radar, use of AIS, and chart plotter. AIS is unreliable. There is no guarantee that all vessels will be using it, and that it will be working. Charts can be inaccurate, making them unreliable for fixed or geographic hazards. And there is the ever possible hazard of large floating debris and wreckage. Though RADAR does have its problems such as noise and back scatter, it is another tool to enhance safety. Considering lives aboard the vessel, and lives aboard nearby vessels, it is well worth it for any vessel engaged in trips longer than day sailing. One of my best memories of how RADAR can be an asset was being aboard a commercial vessel that was navigating a canal in Louisiana in fog at night. We could clearly see the shore lines and all vessels around us. We were able to share the water way by pulling aside for vessels who had right of way. I can see no need for any discussion on pros and cons of its value. The best further use of this thread would be for tips on using RADAR, and how to chose one for various applications and situations, and dealing with technical issues.

[donradcliffe]

Originally Posted by AlanR

"A radar overlay shows you very clearly how far the GPS is off on that specific chart"

It is the chart that is in error, not the GPS or the radar signal.

Not true if the error is in the heading signal. I once spent two weeks trying to get a Garmin system to pick up the right heading.

[donradcliffe]

Originally Posted by Dieseldude

Been reading the posts of arguments for and against radar, use of AIS, and chart plotter. AIS is unreliable. There is no guarantee that all vessels will be using it, and that it will be working. Charts can be inaccurate, making them unreliable for fixed or geographic hazards. And there is the ever possible hazard of large floating debris and wreckage. Though RADAR does have its problems such as noise and back scatter, it is another tool to enhance safety. Considering lives aboard the vessel, and lives aboard nearby vessels, it is well worth it for any vessel engaged in trips longer than day sailing. One of my best memories of how RADAR can be an asset was being aboard a commercial vessel that was navigating a canal in Louisiana in fog at night. We could clearly see the shore lines and all vessels around us. We were able to share the water way by pulling aside for vessels who had right of way. I can see no need for any discussion on pros and cons of its value. The best further use of this thread would be for tips on using RADAR, and how to chose one for various applications and situations, and dealing with technical issues.

Where AIS is clearly superior to radar is on a winding river. You will see the commercial traffic on AIS several turns before you will on radar. As you know most river traffic negotiates passing protocols on the VHF radio and unlike radar, the AIS gives you the name of the vessel to call. BTW, most towboat captains will want you to pass on the inside of the turn.

[Cwens]

Originally Posted by donradcliffe

Not true if the error is in the heading signal. I once spent two weeks trying to get a Garmin system to pick up the right heading.

GPS does not provide heading information. The GPS system knows where it is, but it doesn't know in what direction the boat is pointing. Problems with heading information are coming from some other system, e.g. a magnetic or gyroscopic compass.

[Scorpius]

Originally Posted by donradcliffe

Where AIS is clearly superior to radar is on a winding river. You will see the commercial traffic on AIS several turns before you will on radar. As you know most river traffic negotiates passing protocols on the VHF radio and unlike radar, the AIS gives you the name of the vessel to call. BTW, most towboat captains will want you to pass on the inside of the turn.

Again, both are very valuable and useful. AIS will probably show the commercial traffic - but probably not most of the recreational traffic. Radar shows them all - but perhaps at closer range and without id. Use them both and don't run into anybody.

[Scorpius]

Originally Posted by ChrisOwens

GPS does not provide heading information. The GPS system knows where it is, but it doesn't know in what direction the boat is pointing. Problems with heading information are coming from some other system, e.g. a magnetic or gyroscopic compass.

GPS provides heading information by using a series of positions to figure out which direction you are going.

[donradcliffe]

Originally Posted by Scorpius

GPS provides heading information by using a series of positions to figure out which direction you are going.

Some GPS have built in magnetic heading sensors.

The problem I had was that the bloody boat had 3 heading sensors and one the radar display selected was up to 30 degrees off. I only found two sensors, and could not convince the display to use COG instead. The manuals were lousy and they had to call in a Garmin specialist to get it sorted out. I just used the basic radar display instead of the overlay.

I was not at all happy with Garmin in Maine when a lobster boat popped out of the fog unannounced at a range of 100 yards,

[Cwens]

Originally Posted by Scorpius

GPS provides heading information by using a series of positions to figure out which direction you are going.

Heading is the direction in which the boat is pointing. Course is the direction in which the boat is moving. A compass tells you heading but cannot tell you course. GPS tells you course but cannot tell you heading. (as an aside, there are electronic boxes labeled and marketed as "GPS units" that also contain a magnetic compass.)