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AIS

Started by skylark, October 11, 2011, 09:07:20 PM

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skylark

I have been hearing good things about AIS.  Apparently a lot of larger vessels use it, and if you have one, they "see" you long before they can see you.

AIS is a feature that comes with a VHF radio, correct?  Do you have to connect it to a GPS with a screen to see other ships? 

What would be a basic setup that hopefully doesn't use too much power?

Help a Luddite out!  What is a good type to buy for a simple cruising sailboat?
Paul

Southern Lake Michigan

marujo_sortudo

Personally, I'd consider AIS a luxury item, but if you want it there are essentially two levels.  You can get an AIS receiver (i.e., see the position of ships with AIS transponders.)  Some of these are built-in to VHF, but will need to plug into your GPS, so make sure they are compatible:

http://www.marine-electronics-reviews.com/standard-horizon-gx2150.html
http://www.thehulltruth.com/marine-electronics-forum/265892-standard-horizon-matrix-ais-gx2100.html

Note, however, that these (and most of the more affordable options) do not include a transponder, so the other ships can't see you.  The neat thing about these ones is that they have a little screen that shows you the position of the other ships.  They can be shown on a compatible chartplotter.  I presume that having a transponder would significantly up your power consumption, but maybe someone else can weigh in here, I haven't looked at any myself.

Again, if you want to keep it simple, I wouldn't worry too much about AIS.  Heck, I don't even mind cruising without a chartplotter.  Give me a chart and a GPS and I'm pretty happy.  Remember, almost all the cruisers in the 70's and before (and many still today) went without any electronics or just a little bit.  If you want to go simple and soon, I'd save those $ for cruising kitty.  I say this especially because you self-describe as a Luddite.  Why have systems on board that you're not able to repair and maintain or that frustrate you once you've grown dependent on them?

CharlieJ

#2
My feelings exacty.

I use a Garman 72(non mapping) and charts. Over 5000 miles this cruise.
And JUST passed 1000 miles singlehand :D

Would be nice around New York harbor orplaces like that tho!

I DO know that any thing that transmits use lots of amps. If I were interested I'd go for the reciever only.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

skylark

The main reason I would want the AIS is to send out a message "I am here!" to the big ships. 
Paul

Southern Lake Michigan

Captain Smollett

Quote from: skylark on October 12, 2011, 03:59:34 PM
The main reason I would want the AIS is to send out a message "I am here!" to the big ships. 

How often are you sailing in major shipping waters?

I could be wrong, but I don't think the strength of AIS comes on the open sea.  It seems to me a 'crowded harbor with lots going on' kind of thing...where you  have lots of ships/boats to keep track of and keeping track of the course and speed of each can be difficult (at best, even with a crew person devoted to it full time).

The most crowded 'big guy' waters I've been in:

(1) The ocean approach to Savannah and

(2) The ocean approach and harbor itself of Charleston.

Also been on the Cape Fear River a few times, but it was nothing like these two areas.  The ICW off Pascagoula was sorta busy, too with lighters coming out of the refineries and barge traffic.

In both cases, there was a pretty CONSTANT 'stream' of container ships.  Off Charleston, they were anchored in the offshore anchorage due to fog in the harbor.  When the fog cleared, it was a steady flow both in and out of the harbor..as fast as the pilots could take them in/out.

So, "outside," we stayed inside the line connecting Charleston and the Cape Fear sea buoys, which roughly amounts to staying inside the 10 fathom line.

Once inside the sea buoys, they are pretty much restricted to the deep water channel, so you know where they are and where they are going.

In other words, it's not really that hard to avoid them.  I'm not so sure AIS is that much of a help, at least in THESE types of waters.  Sure, you can transmit your position, course and speed so they know where you are, but it does not really matter that much...they are in the deep water channel, you outside it MOST of the time.  When you are IN it, you are being diligent and not leaving your safety to AIS anyway.

So, that leaves pleasure boats.  THESE are the ones that zip here and there, change course suddenly, run too fast and are too often operated by inattentive (or worse) skippers.

They are unlikely to have AIS...or to have it running.

I can think of places I sure would not mind having it....I just don't know if the expense/power requirements are justified for how little *I* would want to use it.  (Is it's use mandatory if you have it aboard?)

YMMV.

S/V Gaelic Sea
Alberg 30
North Carolina

Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.  -Mark Twain

marujo_sortudo

I has looking into radar reflectors the other day and came across this interesting article, related to "I am here!" idea.

http://www.practical-sailor.com/issues/28_4/riprap/4644-1.html

CharlieJ

Requires you to subscribe at $14 year to read it.

No thanks.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

LooseMoose

We've had AIS for going six years now and I've lost track of the number of times it has been a huge help to us. The biggest advantage of AIS is when getting up close and personal with megayachts, inter island ferries, fishing boats and cruise ships it tells you who the ships are by name and their current course... The big plus is knowing who they are is when hailing someone on VHS if called by name they tend to answer. Having had my radio hails ignored more often than not before this is actually a very helpful feature.

CharlieJ

Do you have the full systems or receiver only?
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

LooseMoose

We have the receiver only...

Vega1860

#10
The problem with AIS on small boats is that, in crowded waterways, there is just too much clutter.  We found that the proximity alarm goes off constantly even with the radius turned down to 1 nm.  Putting the transponder on small boats would overwhelm the system and most skippers would wind up just turning it off as we do in high traffic areas as long as visibility is good.  Of course we avoid the combination of high traffic and low visibility whenever possible. 

The receiver really comes into its own off shore in low visibility.  We set the radius at fifteen nautical miles so we have plenty of time to react if a freighter or cruise ship gets close.  On a recent pacific crossing it was especially useful leaving the coast.  Once away from the coastal shipping lanes we had only two contacts within the 15 nm radius, all the way to Hawaii.

hearsejr

 I helped deliver a boat from southern Fla, to Baltimore MD. we never heard the thing go off till we hit the northern part of the Chesapeake bay. then it was crazy. a line of ships suddenly turned to starboard and dropped anchors and turned their running lights off! the Captain was about to go crazy trying to figure out who was doing what and we threaded through the fleet of 12 ships..while about 10-12 others were anchoring closer to shore. we made it through and the AIS had too much going on for us to take in. they acted like they didn't even know we were there till Doug called one of the ship by name and he said they were waiting for the pilot. 
I guess it's what you perfer. I like to anchor at night away from the channel, beings I have a low budget and only 2 car batteries for power. lol.

marujo_sortudo

Sorry for posting a subscription only link.  It's about radar reflectors and avoiding large ships, but it basically boils down to this.  Examination of boating accidents between big and little ships often involves the appropriate detecting equipment on the large vessels being off, an inattentive operator, or an insufficient amount of time/space for the large ship to alter course/speed to avoid a collision after the small ship has been noticed.  In other words, it's frequently our best plan to depend on ourselves to stay well out of their way.  Hoping for the alternative is often too much.

Some other takeaways:

1.  Interesting quote from Professor Graham King, head of Systems Engineering Research at the Southampton Institute: "within a two-mile range, most vessels over 20 feet are likely to be just as visible without a reflector as with one. However, that level of visibility might in itself be so marginal, especially in poor weather and sea conditions, as to be of little use for collision avoidance between small craft and commercial shipping."  That said, the article still recommends radar reflectors as an assistance, because they might help.

2.  On the high seas, large ships may often have their X-band radar off and their S-band radar set to maximum range which pretty much makes only other large ships visible to them.

3.  Also, another interesting tidbit, from the article: "Masthead strobe lights are very effective. Strictly speaking, these are against the rules, but every ship captain we have spoken to encourages their use on small vessels that are offshore, even in the daytime. If you carry a masthead strobe, be certain also to monitor VHF Channel 16 in case a ship tries to inquire whether your strobe light indicates a request for help. Spreader lights or searchlights on the sails can be very visible in a pinch. "

s/v Faith

AIS: another view.....

Receivers are probably not contributing too much to the 'problem' as I see it, but I do see a slippery slope....
Satisfaction is wanting what you already have.

Captain Smollett

Perhaps the 'Big Brother' aspects are not too far off, but "personal privacy" is a very real concern.

Anyone can view your AIS data on the web or with a smartphone app.

What is interesting to me as I look at this is the SMALL number of vessels it shows.  No doubt, the number of vessels running AIS is a tiny fraction.

It seems, to a point at least, that if only a small number have it, the purported benefits cannot be realized.  Yes, you might increase your odds of "being seen," but by enough to justify the expense?  I mean, if 1 in 5 or 1 in 10 (or less) vessels have it, that means most don't, and thus most won't see your signal if you DO broadcast it.

There is no substitute for "keeping a proper lookout."  Technological tools may help do that, but they cannot replace it.  If the watch stander on the container ship is not paying attention to his AIS, radar out the window or whatever, you are not going to be seen.

Meanwhile, the people that make and sell this stuff are making money by selling the illusion of "better visibility."
S/V Gaelic Sea
Alberg 30
North Carolina

Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.  -Mark Twain

CharlieJ

I think commercial vessels,'at least larger ones, are now required to have AIS.
Charlie J

Lindsey 21 Necessity


On Matagorda Bay
On the Redneck Riviera

s/v Faith

Quote from: CharlieJ on October 14, 2011, 05:45:06 PM
I think commercial vessels,'at least larger ones, are now required to have AIS.

Yes,

  This is accurate.   

For private vessels there are options of 'receive only' or to transmit and receive (AIS B).

The transmitter is roughly the same draw as a VHF, and only transmits for a second every 4 minutes... so the current use is not significant. (relatively)

Keep this in mind though....

One consideration, if you DO have the equipment aboard it is REQUIRED that you employ it when underway....   Colregs require that a proper watch underway use all available assets....   

Just as the decision to have radar aboard carries a technical burden to use it... so also will someone with AIS forfeit the option of turning it off.....
Satisfaction is wanting what you already have.

Monovasia

I mentioned the technology to a friend who installed it on his boat prior to his trip to Costa Rica. His view was it is most definitely worth it, provided him with a view of whose out there and gave the masters his position as well. The shipping lanes up and down the Kali coast are busy, he found it especially useful From Dana Harbor thru San Diego as there was significant Naval traffic transiting the area...
Live slow, Sail fast

matt195583

Old thread but I might be able so share something relevant with you all, I installed a GME receive only AIS unit.

http://www.gme.net.au/products/marine-navigation-systems/marine-navigation-systems-1/AISR120

^  that unit in fact, it cost me $220 for the unit and another $120 for a antenna+base. The antenna is a 7 foot fiberglass unit and is mounted off the bimini frame. The unit feeds the information into the chart plotter and displays the other vessels on the charts,  I get on average 50 mile range out of the unit. I can set a proximity alarm from 300 yards to 3-4 mile and also an alarm for a collision course 3-45 minutes out. I also wired a waterproof 90 decibel peizo alarm into the plotter as the built in alarm was all but useless in any sort of wind or with the motor running. An added bonus is that my anchor drag alarm is now 90 decibels too  :)
     As far as I know all commercial vessels and any private vessels over a given length must transmit AIS.

I had only done a 4-5 days and 2 overnighters coastal sailing before my 4 month trip north last year and was a bit anxious setting out on the longer trip. The AIS really took some of the pressure off when it came to getting through the higher traffic areas and also when off watch ( with pretty inexperienced crew on watch ). Also around the Whitsundays islands where there are lots of charter yachts the charter yachts all transmit AIS signal, not such a bad thing.

I receive their Name, displacement, heading, speed, destination, length and a host of other things.

Don't get me wrong I am very cautious when it comes to keeping a proper lookout and really stress it to my crew, although on one occasion I got up early to find a mate of mine who was crewing with me sound asleep flat out on the cockpit seat. We were travelling near parallel to a rocky shore only 2 miles off to starboard with 3 fishing vessels in sight  ???  When I woke said friend (verbally though not to politley) he couldn't see a problem because he was "keeping an eye on the GPS between dozing". needless to say that particular friend does not sail with me anymore.




ralay

Our boat came with a VHF with an integral AIS receiver.  If it's a luxury, it's my favorite luxury.  We keep a proper watch, but it doesn't do much good when there's no visibility.  On one trip between LA and Freeport, TX we were smacked by a series of squalls as we passed through the region off of Galveston rich with shipping lanes.  During the passage of the squalls, we couldn't see past the bow and the radar readout was one useless blob of red, but the AIS was happily receiving.  I have a picture of the display showing 40 commercial vessels between our boat (which was a ways offshore) and the inlet at Galveston.  It was awfully nice to have some idea what they were up to and exactly whose name to yell into the radio in an emergency.  One of us stayed below to monitor the AIS and tell the helmsman which in direction to strain his/her eyes.  I would think it would be equally helpful in fog.  It wouldn't keep one from smacking an uncharted oil rig or another small boat, but it's better than nothing when that's all your eyes are giving you. 

It's also been useful in narrow channels (ex~ the ICW) as we're never surprised by large boats or barges coming around sharp bends.  Before we've ever seen the vessel, we've already talked to the captain and decided which side to pass, etc.  That's definitely in the convenience category, but it an added benefit if you're already buying an AIS for the more hair-raising situations of picking out ships in open water in poor visibility.

We have a Standard Horizon model.  A new one is ~$330 and draws about .9A when receiving.  It has a small integral display, though we have ours set up to display on the chartplotter as well.