Radar is now redundant ?

[Boatyarddog]

Originally Posted by AlanR

Only seen if the other ship has Radar, it is switched on, and being watched.

Yes, and in the PNW we have a lot of commercial vessels inland.
This is who I wish to be seen by most regularly.
Boatyarddog

[aqfishing]

If I had to choose between radar and AIS I would take radar every time. It’s not even a contest.

However, if you can have both that is a win. There in NO WAY AIS can replace radar. That’s just someone trying to justify not spending the extra $ on a radar. If you cannot afford one then all fair and well, but if you can, you are an absolute fool not to have radar.(unless you only do short day trips in fair weather! )

[Statistical]

Originally Posted by ChrisOwens

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.)

Most GPS receivers can't determine static heading but there are GPS compasses and they are increasingly getting affordable. They use multiple GPS antennas and can determine heading with very high precision.

[aqfishing]

Originally Posted by Statistical

Most GPS receivers can't determine static heading but there are GPS compasses and they are increasingly getting affordable. They use multiple GPS antennas and can determine heading with very high precision.

I have over the last 3 years switched my commercial fishing vessels from fluxgate compass to gps compass. Absolutely brilliant. Improves auto pilot performance quite a bit. Highly recommended. Way better and more reliable than the old fluxgate.

[goboatingnow]

Originally Posted by aqfishing

I have over the last 3 years switched my commercial fishing vessels from fluxgate compass to gps compass. Absolutely brilliant. Improves auto pilot performance quite a bit. Highly recommended. Way better and more reliable than the old fluxgate.

I have one , great piece of kit

[GrowleyMonster]

Originally Posted by Scorpius

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

The "direction you are going" is not the same as your heading. Accurate heading is essential to milking the greatest possible accuracy out of a stabilized display. Your course made good and your heading can differ by several degrees, easily. Your GPS calculates course made good, from comparing two or more recorded positions and calculating the true bearing from one to the other.

Ships use gyrocompasses as the primary heading measurement device, which are very accurate. A large high quality compensated magnetic compass is also very accurate, once the magnetic heading or bearing or course is corrected with variation and deviation. The big problem with magnetic compasses is on the user end. Most recreational boaters do not know how do do a compass check, and so cannot construct a deviation table, and they won't pay a compass adjuster to come do it for them. (another strong case for learning the rudiments of celestial navigation!) Fluxgate electronic compasses are not so very precise, and you are still working with a heading derived magnetically. And so your radar's stabilized display and target plotting can have significant error. That doesn't mean the data is worthless, only that there is a margin of error for you to consider and include when determining your best option for collision avoidance.

Even on ships, I have seen a significant distance between a radar generated target overlaid on the ECDIS or ARPA, and the same vessel's AIS target superimposed on the same display. Of course this is due in part to the location of the antennae of both vessels. You have to have some healthy scepticism regarding ALL of your data, and understand its degree of relevance and in what matter it might be inaccurate or subject to misinterpretation. None of this invalidates the use of radar or AIS. The difference between the position , speed made good or relative speed, course made good or relative, CPA, TCPA, etc should not be seen as confusing, but as one verifying the other within a certain allowance. None of this can replace the Mk 1 eyeball and your ability to watch a visual contact falling off or coming on while you hold a course, but it helps to validate, and gives you a heads up before you can actually see the other vessel.

[CyKlop]

It should be noted that there are several systems that use GPS to determine heading by looking at the difference in position between two different receivers (one at the bow and one at the stern).

[Scorpius]

Originally Posted by ChrisOwens

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.)

I should have realized and noted this. Around here, in a sailboat, if you are not careful, course and heading can be out by 180 degrees!

[Cadence]

Consider, your radar is autonomous.

[Bycrick]

Just a minor detail. I don’t think that GPS compasses work by comparing two (or more) different POSITIONS. One explanation that I saw described the process as using the phase (time differences) between the various receivers. But they work great. I’ve had one for years.

[Pacific Lycia]

I hear that an AIS can be falsely used by some by inserting false information on a ship that isn't there or is there - I don't understand how that can be when one cannot switch AIS off as you please? If that's the case then a Radar will win on that aspect as it cant lie.

However a radar doesn't give you a definition on whats out there, so how does one assume what are they looking at?

Cheers

[Erik de Jong]

It is possible (and not difficult) to put fake targets on AIS tracking websites like Vessel finder or Marine Traffic.
Fake targets in real life are possible, but very unlikely to ever happen.

Fake echo's on a radar are also possible, and not really any more difficult than sending a fake AIS signal into the ether.

[wholybee]

Originally Posted by Pacific Lycia

I hear that an AIS can be falsely used by some by inserting false information on a ship that isn't there or is there - I don't understand how that can be when one cannot switch AIS off as you please? If that's the case then a Radar will win on that aspect as it cant lie.

However a radar doesn't give you a definition on whats out there, so how does one assume what are they looking at?

Cheers

There are a relatively few examples of this. I think some oil tankers have been caught filling up in Venezuela while their AIS showed them elsewhere, and some US warships were spoofed to make it look like they were in unfriendly waters when they were not. I am sure there are other examples.

But those are rare, and not easily accomplished. In both cases it wasn't just showing that something was or wasn't there, the whole point of the spoof was to change *what* was there. And radar doesn't tell you what was there.

Regardless, AIS and radar are different tools. One complements the other, neither is a substitute for the other.

[svfinlandia]

Originally Posted by Erik de Jong

It is possible (and not difficult) to put fake targets on AIS tracking websites like Vessel finder or Marine Traffic.
Fake targets in real life are possible, but very unlikely to ever happen.

Fake echo's on a radar are also possible, and not really any more difficult than sending a fake AIS signal into the ether.

The US Coast Guard uses fake AIS all the time as ATONS.
I ran over one in the Chesapeake a couple of years ago south of Tangier Island. It was marked on the chart, it showed up on AIS, but it wasn’t there.
I am not sure how are you could fake a radar echo though.

Al, S/V Finlandia

[boatpoker]

Originally Posted by svfinlandia

I am not sure how are you could fake a radar echo though.

Al, S/V Finlandia

The US military has messed with radar and all other electronics in the past.
This is a shot of my radar screen going through Hampton Roads two weeks after 911. My VHF got nothing but Static, my GPS produced nonsense and even my depth sounder was a jumbled mess. This all cleared up just before we got to Great Bridge. I have no doubt the US military was messing with UHF, VHF, RF and sonar signals. Same thing happened passing Kings Bay sub station ... We may be seeing that again in the near future.

PS. I am Radar, ARPA, MARPA Certified so know my radar was set up properly