AIS Do I Need It?

[sailorboy1]

Originally Posted by FamilyVan

Hmm, I seem to have managed pretty well with RADAR in the past inspire of intense clutter. Ever tried navigating in a white out blizzard trying to find a track through heavily ridged and broken ice with an AIS? Doesn't work. Tried it with a RADAR? It works great, provided, you have a skilled operator. Buoyed channels are generally not that hard to pick out from the clutter, if you know what you're doing.

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That's great for you, have a cookie.

Guess you completely ignored where I said that people don't need AIS and that I don't have it, and where I said I have radar and that I've worked my way though narrow channels where I couldn't see the bow on my boat. But I guess I have no radar skill

So back to the question: in my opinion you don't need AIS. But if you boat in an area with a lot of shipping lanes I bet you sure will like having it.

[FamilyVan]

Originally Posted by sailorboy1

That's great for you, have a cookie.

Guess you completely ignored where I said that people don't need AIS and that I don't have it, and where I said I have radar and that I'm worked my way though narrow channels where I couldn't see the bow on my boat. But I guess I have no radar skill

So back to the question: in my opinion you don't need AIS. But if you boat in an area with a lot of shipping lanes I bet you sure will like having it.

Is there anything good in the cookie. Does it have anti nausea or relaxation inducing qualities? Will it make me giggle and want more cookies?

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[StuM]

Originally Posted by jwcolby54

Using that logic even the sextant and clock isn't "needed" as it didn't exist before 1730.

Correct. You don't need anything other than your senses, the polynesians and vikings among others did OK without anything else.

However, everything from a compass to AIS adds to the ease of navigation and increases your level of safety. It's just a case of you deciding for yourself what point you want to stop at based on where/how you intend sailing and your budget.

[cabo_sailor]

Originally Posted by a64pilot

One thing we haven't talked about is AIS MOB beacons, after reading a couple of different times about somebody waking up and finding their life long partner missing from the boat, I decided I didn't want that happening to me, so I bought two of these things
Smartfind S20
They have a test mode, and trust me, the alarm that is set off in my Watchmate, will wake the dead. The CPA alarm is a horn noise and will get your attention, but the AIS MOB alert is that annoying two tone European siren sound, and is very much louder than the CPA alarm, if she fell off while I was down below, even asleep, I'd wake up, plus of course I get a GPS aided steer directly to her, so finding her at night isn't nearly the issue it would be without it.

No problem with your sentiment. 100% agree. For myself and my wife we've just gone low tech for now. If only one is on watch, they wear their harness and stay clipped in within the cockpit at night or in bad weather. Under those same conditions, one does not leave the cockpit unless both of us are on deck.

Having said that, I think I will have to expand the possible areas where things go south. Definitely food for thought.

Thanks for post
Rich


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[laika]

I love mine. You don't need it.

I even have an AIS MOB for the dog. Wonderful modern age we live in!

[JPA Cate]

You do not NEED one if you do day sailing in good visibility weather only.

Your AIS is a seductive toy that allows you to see some of the ships some of the time, and some of the sailboats some of the time. Therefore, you have to keep watch based on the premise that outside the range of your vision there may be a non AIS vessel about to get in your way. It is difficult to maintain that level of attention when day after day there's really no one there. Getting lax is VERY hard to avoid.

We just completed a short trip from Oz to New Caledonia with a new Vesper transponder, and i found I actually liked it better when we had only the receiver. The new unit is mounted in the cockpit, and it is a bit too bright for me, but it is both intrusive and [imo] gives a false sense of security. Others' mmv.

Ann

[Sandero]

Originally Posted by Ann T. Cate

You do not NEED one if you do day sailing in good visibility weather only.

Your AIS is a seductive toy that allows you to see some of the ships some of the time, and some of the sailboats some of the time. Therefore, you have to keep watch based on the premise that outside the range of your vision there may be a non AIS vessel about to get in your way. It is difficult to maintain that level of attention when day after day there's really no one there. Getting lax is VERY hard to avoid.

We just completed a short trip from Oz to New Caledonia with a new Vesper transponder, and i found I actually liked it better when we had only the receiver. The new unit is mounted in the cockpit, and it is a bit too bright for me, but it is both intrusive and [imo] gives a false sense of security. Others' mmv.

Ann

This is a good point about "screens" v reality and one's foggy thinking that electronics are better than people and sensing the environment. Sure in one sense electronic transducers and displays can provide metrics that a human can't. But the hazards of sailing are often things that these transducers are blind to. So you can "see" a vessel with AIS that doesn't broadcast and AIS signal. In that sense dumb radar is better at finding "targets" in the environment. It's not perfect either and it is very power hungry.

AIS is an aid bit a substitute for standing watch. And for most it's a handy toy while for some it's mission critical now.

[Rustic Charm]

I have an AIS receiver as part of a built in to my vhf radio. IT works a treat. I love it..

No, I don't 'need' it, anymore than I need a chart plotter. But it's sure nice to have it. Highly recommend. If you can afford a transponder go for that one too.

[SimonV]

There is also the fact that governments can, and do use AIS to monitor the movement of shipping. AND have prosecuted fishing vessels on AIS information.

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[Rustic Charm]

Originally Posted by SimonV

There is also the fact that governments can and do use AIS to monitor the movement of shipping and have prosecuted fishing vessels.

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And is this a bad thing or a good thing your suggesting?

[Jon Eisberg]

Originally Posted by zboss

I believe that an AIS transceiver should be mandatory on all new boats going into production.

Hmmm, careful what you wish for, when every boat on the water is transmitting AIS, that may not necessarily be a good thing... I can easily foresee that ultimately having the effect of the Big Boys filtering you out in certain situations...

;-)

Attachment 63361

I'm mainly concerned about one of these vessels showing up on my AIS... The other one, not quite so much...

;-)

[Dockhead]

Originally Posted by mjcook

Do cruiser need AIS and if so what should I get?

This is the rare question asked on here which has an absolutely clear one-word answer:

Yes.

That was a period after the Yes.


What to get, however, depends on other systems on board. If you have a modern MFD (capable of displaying AIS dad) at the helm, then a black box transponder is the most cost-effective and convenient.

If you use PC navigation systems, then OpenCPN (and probably others) has really excellent display of AIS data produced by a black box transponder.

If you use an IPad or other mobile device, there are black box devices (Digital Yacht? Others?) which will stream the AIS data and maybe other boat data if you have compatible devices to the IPad.

If you want something freestanding, everyone praises the Vesper systems.

What to get is much less important than getting it at all. Once you try it, you will never want to be without it. Having AIS is a no-brainer.

[Dockhead]

Originally Posted by Ann T. Cate

You do not NEED one if you do day sailing in good visibility weather only.

Your AIS is a seductive toy that allows you to see some of the ships some of the time, and some of the sailboats some of the time. Therefore, you have to keep watch based on the premise that outside the range of your vision there may be a non AIS vessel about to get in your way. It is difficult to maintain that level of attention when day after day there's really no one there. Getting lax is VERY hard to avoid.

We just completed a short trip from Oz to New Caledonia with a new Vesper transponder, and i found I actually liked it better when we had only the receiver. The new unit is mounted in the cockpit, and it is a bit too bright for me, but it is both intrusive and [imo] gives a false sense of security. Others' mmv.

Ann

Seductive "toy"?

I beg to disagree. No more "seductive" and no more "toy" than nav lights or bilge pumps or GPS navigation. All of which, can be argued, make you "lax".

AIS is an extremely powerful tool for avoiding collisions -- really the killer app for collision avoidance which completely changes the game. If your system is properly installed, you can rely on it for detecting ships and calculating your crossing with it -- and that's what AIS is intended for. On a rare occasion a ship might have a malfunctioning AIS, but I can't recall seeing a single case of this in three years and thousands of ship encounters in that time.

Just like you do rely on nav lights being shown, for seeing traffic on a dark night, even though there may be rare cases where the nav lights are out. I've seen sailboats with broken nav lights, but can't recall ever seeing a ship with the nav lights out, in so many years of sailing in the busiest seaways in the world.

Having AIS doesn't mean you can give up keeping a visual watch, but it is perfectly fine to make AIS your primary means of detecting ship traffic -- as it was intended. Back it up with radar with guard zones set to cover F/V's which have switched off their AIS to fox their competitors, and recreational vessels which don't have it, and on top of that keep a good lookout, and this is the correct approach to detection of traffic as the first (and most important) phase of collision avoidance.


The second part of collision avoidance is calculating your crossing -- what's the CPA? TCPA? Passing ahead or astern? How fast is he going? These are crucial data which you need, sometimes quickly, in order to maneuver safely to prevent a collision. On top of that, you get the identity of the ship, MMSI, callsign, so you can call it up on VHF if you need to, and won't confuse it with a different vessel (which can have fatal consequences). Without AIS, you have a few options, all greatly inferior, in order of effectiveness:

1. ARPA or MARPA on your radar. Theoretically gives you the same data as AIS (other than identity of the ship), but very poor effectiveness on all the recreational radars I've ever used. Some Furuno owners report better performance.

2. Radar with a hand plot. Can be pretty effective with a good radar (properly aligned and set and fed with good compass data). But how many cruisers even know how to do this? And even if you have the skills, how many targets can you manage at once? In busy waters, you will be overwhelmed.

3. Hand bearing compass and record of bearing change. Standard operating procedure for yachtsmen before AIS came out. But it only tells you one thing -- ship clearly passing ahead? Or behind? Or within the large margin of error of the method -- constant bearing and collision risk. It doesn't tell you CPA, TCPA, speed of the other vessel, or anything else. And it is only reasonably accurate when you're already close enough that it starts to get hard to avoid the collision. On top of all this, you have the same problem as does hand plotting with radar data -- you can't manage many targets at once. Even worse here since you only start to get more or less valid data when you're pretty close.

4. Eyeball and try to scamper out of the way when a big scary ship appears. I hate to say it, but my impression is that at least 80% of cruisers who don't have AIS, rely on this method, and what's even worse, they combine this method (if you can even call it that) with ignorance of and/or willful disobedience of the COLREGS. A minority of those know to guess the bearing change by transit with a stanchion etc. This method is almost totally ineffective because you can't just eyeball other traffic at any distance and distinguish between collision risk and very safe crossings, and you don't know which way to turn, or whether even you need to turn. When you cross paths with fast moving ships in open waters, you have to make decisions at least 5 to 8 miles out -- far beyond the range where you can tell anything at all by eyeball. In reality, such sailors are just flotsam, as far as traffic is concerned, and are treated as such -- the whole job of collision avoidance is done by the ship's helmsman, who assume you are a dangerous idiot and steer a wide berth before you are even aware they are there. This is not a desirable situation.

[FamilyVan]

DH, I think your point brings us back to a point made by The Penguin early on in this thread. Where (and how) do you sail?

If I have had any success at deciphering CF posts, my understanding is you sail in the English Channel, North Sea and the Baltic including a recent long distance run to Sweden. I would definitely want an AIS and RADAR for that trip.

I currently Bob around in the Thousand Islands, but avoid the main shipping channel, in these islands, none of the small vessels you encounter have AIS . I do have a receiver, which I purchased when I was in busier waters and I like to sail in cruddy conditions, but for the thousand islands I rarely bother going down stairs and turning it on.

Ann stated she recently did a trip from Queensland to New Caledonia, which I had to Google, but I can't imagine that area has the same kind of traffic density or reduced visibility as the North Sea. Now this looks like some serious offshore cruising, so I would definitely be inclined to want an AIS for that trip, because you're going to be beyond short term weather forecasting.

As for the OP, I don't think I know where he sails, or even what kind of boat he's on.

I agree that for some cruisers (like yourself) an AIS could be considered critical, others (like me) occasionally quite useful and still others, not much use at all.

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[a64pilot]

Originally Posted by cabo_sailor

No problem with your sentiment. 100% agree. For myself and my wife we've just gone low tech for now. If only one is on watch, they wear their harness and stay clipped in within the cockpit at night or in bad weather. Under those same conditions, one does not leave the cockpit unless both of us are on deck.
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That is said by a lot of people to be a standing rule, yet MOB still happens. I can see it happening to me. About three in the morning I decide I've had enough of that Damn Genoa halyard slapping the mast and decide to do something about it, Wx is fine, no point in waking her and I slip and fall in, never fell in before. Really it's the thought of the grief she would feel and she would blame herself that worries me more than the thought of dieing.
And if the Wx is crap, especially on a very dark night, you may not be able to get turned around and find someone even if you see them fall in. Even if they have a radio, hard rain, 50 kt squall reduces vis to almost nothing, yet your being blown at a very high speed away from them.
But really I just want to point out that AIS is as far as I can tell the absolute best method of finding a MOB that I can come up with, it's not just for keeping yourself from being run down by a ship. AIS does FOUR things, not just the three most think about.

Vesper is not just stand alone, it has an Ipad app and is Wifi as well.

But this just keeps going to I have Radar, I don't need AIS, or Radar is better than AIS etc.
Well, I have a main and headsails, most of my speed seems to come from my headsails, but I don't think I don't need my Main? They seem to complement each other very well, If I said save your money don't buy a main sail, you would all think I'm nuts, or if I said you have charts, you don't need a depth finder.
AIS complements Radar, just like my main does my headsails, or my chart plotter and depth finder, they are two completely different technologies, but work well together, one does not replace the other.