Does one really need Radar AND AIS

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3reefs

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I have a plotter that can receive AIS from an "engine". Had a look at a simulation and began to wonder ... if the plotter tells you where the fixed hazards are and AIS tells you about the larger moving hazards ... does radar really add that much?
 
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I have a plotter that can receive AIS from an "engine". Had a look at a simulation and began to wonder ... if the plotter tells you where the fixed hazards are and AIS tells you about the larger moving hazards ... does radar really add that much?

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Briefly, yes!

Radar will pick up all the vessels of less than 300grt in your vicinity that are not compelled to have AIS systems, those over 300grt that might have forgotten to switch AIS on and vessels permitted not to trnasmit AIS such as military vessels.

If that isn't enough, using AIS only for collision avoidance should only be done with the realisation that AIS systems are using an "earth" based reference (from GPS) for all collision avoidance calculations. Vessels at sea tend to be travelling on a moving body of water, not all of which is moving at the same speed. Thus the relative motion calculations should use speed and heading through the body of water for accurate CPA and TCPA calculations, and this is how radar should and can be used.
 
Radar shows you the small ones that don't have AIS transmitters.

AIS gives you the name and MMSI of the vessel that may be giving you concern. This means that you can contact them without saying "The vessel on my starboard bow". or something equally unhelpful.
 
...and the AIS versus Radar discussion continues. There are many threads on this forum about the subject, but in brief,

AIS depends upon other ships transmitting. It also depend upon correct data being transmitted, and as has been found, AIS data can be completely wrong showing incorrect targets etc.

Radar places you in control with the ability to see what's going on around you regardless of anyone else. You can also use radar for navigation.

By the way, the Col Regs make specific mention of using radar, and not of AIS.

So in answer to your qn, I would suggest install radar first, then AIS if you have the funds.

Interestingly, a ferry skipper has told me he is getting fed up with being called by small boats in the channel, and has ceased to respond. Most of the calls have been about action to avoid collision. Before not responding at all, he simply used to state 'follow the Col Regs, that's what they are there for. Out.'

When will these discussions cease? Marketing AIS as AIS Radar has made so many people think they are safe. I wonder how long it will be before the first AIS induced accident?
 
Radar can be used for navigation in the event that you lose your GPS input! But hey Nelson had neither and still won Trafalgar.....
 
I think Radar is jolly useful but there are a number of reasons why you might prefer not to fit it. I can't think of any reason for not hooking up the AIS though.
 
I think the answer is No
You don't NEED them.

But

They do completely different jobs and one isn't a replacement for the other

Both are handy tools but you dont need them


Rob
 
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No you don't need them...unless you are out at night, get caught in fog or other poor vis., want to cat-nap etc.

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Even then.......You still don't need them, they are just suppliments to good seamanship......toys to make life easier, for the hard of sailing! /forums/images/graemlins/grin.gif
 
As mentioned above one can do without them, mariners did for centuaries, at least the ones who survived did.

In my opinion you can never have too much information about the sea and ships around you, thus if you can afford both then get them. Information about the threats to your safety helps you keep safe so is valuable. Even in good conditions they can give you informaion about dangers that you would not get from other sources, and in reduced visibility they help even more.
 
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By the way, the Col Regs make specific mention of using radar, and not of AIS.

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Whilst I agree with all your other points, I think this one is completely irrelevant and just serves to devalue your argument.

Rick
 
Even then.......You still don't need them, they are just suppliments to good seamanship......

I agree they are supplimentary, but then you become reliant on the others.... which regretably sometimes doesn't work.

........................................................................................
For the rest...
I suppose it depends on ones definition of need. For example, let's say your first mate says" I need a crap!"
You say " no you don't NEED one, you might like one, but not NEED one"

Similar sort of thing with radar, you don't need it but it could keep you from becomeing knee deep in [--word removed--]!
 
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Interestingly, a ferry skipper has told me he is getting fed up with being called by small boats in the channel, and has ceased to respond. Most of the calls have been about action to avoid collision.


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So if this character had been skippering the POB and recieved a call from the Ouzo saying something like "I am the yacht a mile in front of you fine on your starboard bow. You have just turned towards me. Just checking you have seen us" he would have ignored it? As you say, interesting...
 
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Even then.......You still don't need them, they are just suppliments to good seamanship......

"I agree they are supplimentary, but then you become reliant on the others.... which regretably sometimes doesn't work."

Are you saying that Good Seamanship doesn't work??.......It's electronics that will let you down, most likely when you "need" them the most..........like I said, toys for the hard of sailing.
 
Are you saying that Good Seamanship doesn't work??.......

No, not at all and I agree with your point re equipment.

I am saying that to rely on others does not always work out. Yes fine if they are doing a good job but in a pea soup good seamanship is required by <u>everybody</u> and regretably 'everybody' is not always awake. So for me to be able to pick up the potential problem earlier rather than at the last minute has to give me a better chance of not getting run down because I could not get out of the way fast enough.
 
Most sailors on these forums are not used to a radar picture, and find it very difficult to interpret what they are seeing.

AIS and radar are complementary rather than either or,

Furthermore AIS can help a radar newbie understand what he is seeing on the screen.

Radar not only can provide you with data on ships that are not using ais like fishing vessels, other small vesels (and a lot of feries!), but will also give you navigational information.

AIS is a lot cheaper, but can give you identities and cpa much earlier than radar.
 
You don't actually need to go sailing!

But we want to.

We also want some good tools to do it safely, especially if you cruise further afield and for night sails.

As you say, you don't Need either, nor do you need GPS etc.

But we want to have them. (we as in a lot of yotties)

Of the two, I recommend radar. It will help with navigation. AIS would be excellent if you sail in busy shipping lanes. Here in the Bristol Channel, ther would be few contacts.

IMHO
 
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