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Old 06-02-2019, 07:31   #1
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AIS INSTEAD of radar?

My old Autohelm radar finally died. One of the electronics guys I was talking to suggested that if I installed AIS I really didn't need to replace the radar. The fact is that I almost never used my radar unless I was closing on a coast or looking for a reef. Another friend who’s boat is in New Zealand is really enthusiastic about the Vesper Marine “smart AIS”. I plan on putting a Raymarine MFD in the cockpit at the helm station (I already have one below at the nav station) that will repeat the chart and display the AIS information. Any comments about the need for both radar and AIS?
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Old 06-02-2019, 07:37   #2
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Re: AIS INSTEAD of radar?

I go for AIS over radar. Cheaper too. But, I'm not sailing where there's fog and I'm mainly sailing far out at sea where the vast majority of other vessels have an AIS transponder.
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Old 06-02-2019, 07:51   #3
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Re: AIS INSTEAD of radar?

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Originally Posted by callistov42 View Post
The fact is that I almost never used my radar unless I was closing on a coast or looking for a reef.

AIS wont show you the coast or a reef.


They are really quite different things that compliment each other rather than replace each other. Depending on what type of sailing you do and how much other traffic there is around in your area either one could be more important. We have both and I'd replace either if it failed.


The Vesper stuff is well made, we have the XB6000 and are well pleased with it.
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Old 06-02-2019, 07:53   #4
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Re: AIS INSTEAD of radar?

Radar is very useful for things that have nothing to do with boat collisions. Just a few of the things I have experienced (non collision related):
-making landfall into a hidden harbor under gale conditions fro open ocean. Waves at 10 feet approaching shore. Blind entry into harbor. Sea floor getting shallow. Essentially heading the boat into a dangerous rocky leeshore under those conditions. With Radar I could see the blind entry... looked just like the chart.
- Crossing the gulf stream with a several waterspouts active. Track them on radar and avoid them
-Landing at a port of entry at night. Totally dark out. The crossing took a few hours longer than predicted. Successfully entered harbor and anchored for the night.
-Crossing at night in the Caribe. Huge active thundercells 60+ miles away. Was able to track the storms all night on the radar.

One collision related situation that I have experienced a few different times:
Rag tag fishing fleets working at night with nets out over a wide area. These junky third world boats have no AIS signal. You cant see the long nets, the boats are everywhere, maybe 20 boats over a few square miles. You can just avoid the whole group with radar.
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Old 06-02-2019, 08:00   #5
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Re: AIS INSTEAD of radar?

AIS in addition to radar.

AIS does not show coastline, weather patterns (squalls, etc.), or boats that do not use AIS. For safety you should have and use both.

Vesper AIS is amazing. I really like the built-in Anchor Alarm function.
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Old 06-02-2019, 08:01   #6
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Re: AIS INSTEAD of radar?

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Originally Posted by callistov42 View Post
My old Autohelm radar finally died. One of the electronics guys I was talking to suggested that if I installed AIS I really didn't need to replace the radar. The fact is that I almost never used my radar unless I was closing on a coast or looking for a reef. Another friend who’s boat is in New Zealand is really enthusiastic about the Vesper Marine “smart AIS”. I plan on putting a Raymarine MFD in the cockpit at the helm station (I already have one below at the nav station) that will repeat the chart and display the AIS information. Any comments about the need for both radar and AIS?
This is very much like asking a woodworker if he wants a hammer OR a saw. It's a false dichotomy.

AIS is wonderful at what it does, but it will not help you when you are closing on a coast at night or looking for the reef. It no more replaces RADAR than it replaces the need to keep a good visual lookout.

Even in clear daylight, a good modern RADAR with MARPA will help you evaluate easier and more accurately meeting/crossing situations with boats that don't have AIS than you can visually. The new doppler RADARS even more so. Most small boats do not have AIS. I have seen an oceangoing ship that was not broadcasting an AIS signal. Most Naval vessels do not broadcast AIS when on the high seas. Many fishing vessels do not broadcast an AIS signal. Picking out an unlighted ATN at night the RADAR is awesome. Coming into a crowded anchorage at night a modern RADAR is a very valuable tool to orient and find the best spot between the other boats.

Being able to overlay AIS targets with RADAR returns really gives me a great sense of security that I have the situation properly evaluated.

Neither AIS nor RADAR is required, of course, and both are very helpful. They overlap in function, but the idea that one replaces the other is wrong.
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Old 06-02-2019, 08:03   #7
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Re: AIS INSTEAD of radar?

We have both (well, ais receiver soon to be transponder). I would go AIS prior to radar, unless I was frequenting areas with fog or doing lots of night entries.
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Old 06-02-2019, 08:08   #8
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Re: AIS INSTEAD of radar?

Those 2 electronic nav aids are not substitutes for each other.

One helps to identify other vessels that happen to be equipped with AIS and provides vector information on their relative course and speed to alert you to a close quarter situation.

Whereas Radar provides the same vector information for ALL targets, be it vessels, islands, unlit fishing boats, fish attenuators and large floating debris.
Using parallel indexing techniques from coastal targets, a watch keeper can constantly fix and update boats position and verify GPS driven electronic chart accuracy, independent of any operator or system errors in plotting course on ECS.

AIS is a limited plug and play Navaid..

Radar is a far more powerful Navaid, for Day / Night and restricted visibility Operations.

However Radar requires training and practice in tuning by the operator.... to be used with confidence.

Since the majority of pleasure boaters do not have the training in Radar operation, its use and value are not appreciated.

If I could only choose one...it would be Radar.
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Old 06-02-2019, 08:26   #9
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Re: AIS INSTEAD of radar?

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Those 2 electronic nav aids are not substitutes for each other.
....
If I could only choose one...it would be Radar.
I agree 100%.
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Old 06-02-2019, 08:39   #10
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Re: AIS INSTEAD of radar?

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Originally Posted by billknny View Post
This is very much like asking a woodworker if he wants a hammer OR a saw. It's a false dichotomy.


. . .


Neither AIS nor RADAR is required, of course, and both are very helpful. They overlap in function, but the idea that one replaces the other is wrong.

Indeed.


This has been much discussed in the last year or so, so a trawl through the archives would be illuminating for the OP.


AIS and radar serve different functions, and both very important ones for boats which are used offshore, at night, in traffic, and in different weather conditions (fair weather weekend sailing is different).


I would not want to be without either AIS or radar, but if you want to know what is MOST important, for me that is definitely radar, something which for me is more important than any other electronic device on board the possible sole exception of the depth sounder.



Radar is a powerful and versatile device which performs many valuable, and sometimes possibly life-saving functions. AIS sees only what is broadcasting. Chart plotter shows only what is charted, and only WHERE it's charted, not necessarily where it IS*. Only radar actually sees everything, and sees it where it actually is. Not only vessels, but coastlines, buoys, rocks, landmarks, even weather.


I would really be lost without radar on my boat.






* I spent the summer in the Arctic where the charts are basically useless -- off by a couple of miles if they even represent the shape of the coast correctly, which they generally do not. No landmarks, so no fixing position with a HBC. Radar saved the day -- I spent the whole summer navigating primarily with radar.
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Old 06-02-2019, 08:46   #11
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Re: AIS INSTEAD of radar?

As others have said, the two are not different tools for the same task. They are quite different in function and capabilities. As I’m sure you know, AIS is completely useless for tracking an approaching "coast or looking for a reef.”

There is an overlap with the capacity to “see” some vessels. But even that is relatively small. Not all vessels transmit an AIS signal. Most of the larger ones will, but most of the small will not. Radar can miss things as well, but it doesn’t do it by design.

Radar is a general tool that lets the user see what is actually out there. AIS is a narrow tool that displays an approximation of a small part of what may be out there.

The way I would frame this questions is whether you need radar, or need AIS. There are plenty of areas where radar is mostly useless, or not really needed. Same goes for AIS. Cost in terms of money and effort are much easier for AIS vs radar, so a cost-benefit analysis would swing towards AIS.

But they are not interchangeable tools.
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Old 06-02-2019, 08:48   #12
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Re: AIS INSTEAD of radar?

Quote:
Originally Posted by Pelagic View Post
Those 2 electronic nav aids are not substitutes for each other.

One helps to identify other vessels that happen to be equipped with AIS and provides vector information on their relative course and speed to alert you to a close quarter situation.

Whereas Radar provides the same vector information for ALL targets, be it vessels, islands, unlit fishing boats, fish attenuators and large floating debris.
Using parallel indexing techniques from coastal targets, a watch keeper can constantly fix and update boats position and verify GPS driven electronic chart accuracy, independent of any operator or system errors in plotting course on ECS.

AIS is a limited plug and play Navaid..

Radar is a far more powerful Navaid, for Day / Night and restricted visibility Operations.

However Radar requires training and practice in tuning by the operator.... to be used with confidence.

Since the majority of pleasure boaters do not have the training in Radar operation, its use and value are not appreciated.

If I could only choose one...it would be Radar.

A small quibble -- radar doesn't actually give you "the same vector information" on other vessels, which AIS does -- small boat radar does not have the bearing discrimination to allow you to do a decent radar plot on another vessel, whether by MARPA or by hand. It's good enough to do effective collision avoidance, but far less accurate than what you get from AIS, plus the virtual plot you get from AIS is instantaneous, which is really useful for collision avoidance. See this is just one reason why they are not substitutes for one another.


I do covet a large open array radar, maybe a pulse compression or HALO one, like I bet Pelagic has got That's high on my wish list, although my B&G 4G radar does most everything else OK more or less.




As to training -- YES, what Pelagic said is true and important. Radar is not a tool you can just switch on and go, so hard for the video game generation to use effectively. Radar training is really valuable, and without it, it is doubtful whether you can use your radar to its full potential, if at all.
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Old 06-02-2019, 08:48   #13
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Re: AIS INSTEAD of radar?

NO, just simply NO.
AIS is not a substitute for radar.
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Old 06-02-2019, 08:51   #14
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Re: AIS INSTEAD of radar?

As others have said, they are different tools that do different things.

I've found both invaluable, though if you don't sail at night or in fog much, AIS would probably be more useful than radar (although cheating when anchoring and using the radar to tell range from other boats is always nice )

As a single-hander I wouldn't be without either though (guard zones are the BEST, stopped me running into a dead whale(!))

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As to training -- YES, what Pelagic said is true and important. Radar is not a tool you can just switch on and go, so hard for the video game generation to use effectively. Radar training is really valuable, and without it, it is doubtful whether you can use your radar to its full potential, if at all.
I dunno if radar training is needed but even reading the damn manual and playing with the settings on a calm open day is invaluable. And practice practice practice, the more I use the radar the more I realise just how damn useful it is)
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Old 06-02-2019, 09:03   #15
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Re: AIS INSTEAD of radar?

I'm in Galveston and sail single handed offshore (Gulf of Mexico). NONE of the 3,000 plus oil and gas rigs or pipes in Texas waters alone have AIS. Just something to consider.
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