Radar is now redundant ?

[Emouchet]

Do not think that because the display is nice and crisp that the chart is accurate.
You will be surprise to know that most charts have been mapped years before the GPS.

So that may not be that accurate. Especially in areas that are not used by commercial ship.

How to Read a Nautical Chart, 2nd Edition, by Nigel Calder will most probably blow your mind.

[Lionshooter]

Times have changed for sailors these days...45 years ago, I was delivering boats to other countries with a compass, a sextant, an RDF, and eyeballs.

[ameehan]

As a former professional navigator I can state that radar is used for pilotage (e Teri and leaving port) exclusively by all pilots and masters. The benefits for collision avoidance and in restricted ability are obvious.
AM

[Cwens]

"The difference between theory and practice is a lot greater in practice than it is in theory."

Your chart, whether paper or digital, shows the location of navaids in theory -- where the chartmaker believed them to be at the time the chart was made. Your radar shows where they are in reality right now. Buoys can be surprisingly far from their charted location, even in the first world, either because they dragged anchor or because of an error in charting.


There is fishing gear marked with radar reflective buoys at each end, that is a lot bigger than I would want to run into, surprisingly far offshore.


Many, many boats don't transmit AIS.

[goboatingnow]

Originally Posted by Martkimwat

AIS is wonderful thing but relies on a GPS position. If the GPS service goes down, either through sunspot activity or denial of service for whatever reason (hackers, foreign powers emergency powers etc) then not only do you not have your position, but you also don't have AIS information. Radar will still work though and is not affected by outside forces such as GPS errors or whatever, what you see is what you got.

if 4 worldwide independent GNSS systems ( weve moved on a long way from GPS) go down , the last thing ( !!) you ll worry about is your location

[Martkimwat]

Originally Posted by rslifkin

Same thing in the US. But if you're out in heavy fog with no radar, they might pick on some other points for considering that irresponsible.

I would say it depends on where and how you got there. I don't have radar on my small (26 ft) sailing vessel, and I do occasionally go out in fog if I know it is only a local fog bank that will burn off and I keep to the out side of the shipping channels. I have not yet, nor hope ever to be caught out in open water in fog until such time as I can afford a modern radar head, but it can happen, especially in the English Channel or Irish Sea. Until then I can only rely on class B AIS, Chartplotter and a Sea-Me Active S and X band radar enhancer(so others can hopefully at least see me) and a good set of eyes and ears.

[Paul Howard]

Areas where radar is most useful are foggy, like Eastern Canada and U.S. We spotted icebergs on the radar when sailing from the Straits of Belle Ilse to Iceland, though it was the proper time of year when it never gets dark in those latitudes, icebergs create their own fog. Or when sailing from Bermuda to New York when encountering a fleet of fishing boats in dense fog as we approached the coast. Or on the British Columbia coast when the ferry boats come up the inside passage in dense fog, sounding their fog horn and you can hear but not see them.
There is an anchorage in Southeast Alaska called Foggy Bay, the first place to anchor when crossing from British Columbia to Alaska. The four times I crossed the Dixon Entrance it was very foggy and there were fleets of small salmon fishing boats and their nets everywhere. If they think you are going to run onto their nets they charge at your boat to try to divert you, radar is necessary.
Or when cargo ships come out of dense rain squalls in the InterTropical Convergence Zone, etc., etc. if you are hanging around the Caribbean there is probably little use for Radar, but if you are a serious ocean crossing cruiser seeking interesting places, you should have radar.

[Scorpius]

Originally Posted by requiem

We use MLLW here in the States too. Other places might use LAT.

My money would be on old survey data. If it's not something you regularly check, you might be surprised at when many places were last surveyed.

My point was we DON'T use MLLW. We use LLLW - and the difference can be substantial. In the past several years I think I've only seen one negative tide prediction in the area - and that was only -.1 foot for a SUPER King Tide.

And yes, the survey data for many charts is very old. Much of our coast was charted in the heyday of Union Steamships (and at their behest - 1920's through 1950's). Charts seem only to be updated if there is significant commercial traffic in the area.

[Martkimwat]

Originally Posted by goboatingnow

if 4 worldwide independent GNSS systems ( weve moved on a long way from GPS) go down , the last thing ( !!) you ll worry about is your location

They can all still be affected by local, malicious denial of service by someone with a strong 'spoofing' transmitter, it does not even need to be that powerful, since GPS signals are so weak (100s of miles between satellite transmission and your reception) it is why those airfields that allow primary GPS aided approaches all have a local GPS enhancing system(Differential GPS) to provide a strong GPS type signal which will allow or alert an approaching aircraft to detect if the GPS signal is being spoofed. My Garmin GPS head on my boat is only five years old but I have seen a few instances where my position has been off by fifty or a hundred feet or so. No big deal whilst out in the open, a major catastrophe if I was trying to enter a narrow harbour entrance at night and some navigation lights were out of service for whatever reason. Radar would give me certainty. Unfortunately there are idiots who think it's 'fun' to do this type of spoofing and the equipment to do it is readily available and not that expensive. (don't know if you've had it in the USA but we have regular occurrences of idiots shining powerful lazers at approaching aircraft because they think it's fun, and a couple of years back our local airport London Gatwick International (LGW) was closed for nearly 24 hours whilst police tried to catch some idiots who were flying drones and playing chicken with aircraft on landing approach. So it doesn't need a major World incident to deny you accurate GPS( and by extension AIS) information, just some bored brainless t**t with a bit of cash to spare....In addition, just because there are four different Global Positioning System out there, does not mean your GPS set will be able to receive them, they are mutually exclusive systems, not complementary. Unless you have and can afford the newest and most expensive navigation receiver that can receive several (but not all ) of these signals, you are likely only going to be able to use the original US based GPS system.

[deblen]

In Canadian waters,any vessel less than 20metres(66ft) is not required to carry AIS.
No Canadian yacht(pleasure vessel) regardless of size is required to carry AIS.
Personal experience: Of the approx.150 com.fishing vessels based on GMI,less than 10 currently are equipped with AIS.These are all 40-70 ft. vessels.
Cheers/Len


https://laws-lois.justice.gc.ca/eng/...e-3.html#s-118


It appears from the following link that the AIS requirement situation is very simular in US waters.
https://www.navcen.uscg.gov/?pageNam...equirementsRev


I humbly suggest that radar be retained & used for the forseeable future.

[Catboat Willy]

Ever sail at night in Maine ? Radar, it's about having the right tool to use at the right time.

[Toys_with_time]

Originally Posted by sailingunity

I've used it from time to time to track storm cells that were nearby, to see if they were approaching or not. Also when exiting a harbor in dense fog, I was able to see the markers (though admittedly, the charts show this too). I don't have functioning radar anymore (the chartplotter crapped out) and I've gone back and forth on whether to get one.

Agree great for tracking squalls and also to show them up at night. Naval vessels don’t transmit AIS and once ended up in the middle of a NATO submarine hunting exercise (my bad) and radar helped me plot a course out of there which was made even harder because they don’t keep to straight courses when hunting subs. Moral of the story - don’t plot a course through an area marked on the chart as “Submarine exercise area”

TwT

[Bycrick]

All it will take to lose ALL the GNSS systems is another Carrington-like event. Is that a once-in-a-hundred-fifty years event? Yes. Is it likely to happen tomorrow? No! Could it happen tomorrow? Yes! If it happened, you’d have lots of problems besides not finding your way home. But, people buy life rafts and fire extinguishers for low probability events.

I use every tool I can get because I need all the help I can get.

When you have radar, you need to learn how to use it, how to tune it (even though it claims to tune automatically) and how to interpret the display. It isn’t like you see in the movies. .

[MoodyS]

A little tale for you that has most of the elements covered above, including the "everyone has AIS" nonsense. A few years ago I was still learning to interpret the radar screen and sailing a couple of miles off the Med Coast of Spain I decided to add interest to the night watch by identifying the radar targets inside my 3 mile horizon. All went well until I found a solid target but no AIS and I just couldn't pick out any nav. lights through the binoculars no matter how hard I looked. Until, silhouetted against the foreshore street lights of Torremolinos, I discerned the dark shape of a power boat. As I watched it did a U-turn and closed to a quarter mile astern. At 200m I roused my crew and put out a Pan-Pan on ch 16 giving my location. The Spanish coastguard responded, as did the customs cutter astern which promptly lit up like a Christmas tree. It all ended well over a cup of tea and a bit of form filling in our saloon. But, it really does help to know what is going on around you by any means possible.

[goboatingnow]

Originally Posted by Bycrick

All it will take to lose ALL the GNSS systems is another Carrington-like event. Is that a once-in-a-hundred-fifty years event? Yes. Is it likely to happen tomorrow? No! Could it happen tomorrow? Yes! If it happened, you’d have lots of problems besides not finding your way home. But, people buy life rafts and fire extinguishers for low probability events.

I use every tool I can get because I need all the help I can get.

When you have radar, you need to learn how to use it, how to tune it (even though it claims to tune automatically) and how to interpret the display. It isn’t like you see in the movies. .

not really true , https://www.raeng.org.uk/publication...er-full-report

in the meantime GNSS will do nicely thank you