Not using your AIS

[Roy M]

When I do installs of AIS for fishermen, they generally request my adding a switch that allows them to turn off their transmit function, yet retain the receive mode, so other fishermen can't tell where they are located. Some sail racers, also, like to have the option should they choose to exercise some secrecy in their tactical decisions. Like, the sun is going down, and if they choose to cut in close to the beach they can avail themselves of the light airs coming off the land. I call it the "black" switch. Easy enough to do.

[barnakiel]

E.g. good visibility and no ships around = no need to fire up AIS and burn Amps.

Etc.

b.

[Roy M]

170 milliamps average for the em-trak AIS.

[CdS2 Roland]

In some "dangerous" places we turn off transmission on a class B AIS. Keep reception on.

[Juho]

I have understood that some rich and famous prefer not to announce their whereabouts, and therefore switch off their AIS whenever that is ok.

[Doug Brown]

When I was carrying ammunition to and from Israel onboard the privately owned container ship I captained (she was not a government or military ship) I use to put in all sorts of inaccurate information so the "not friendlies" couldn't easily track the ship.

This is a few years back when the north coast of Africa was going through their "Arab Spring" and we weren't the most popular country in the world (things haven't changed that much since then...)

Israel was very insistent that we never showed them as our destination.

When we were in areas of high traffic (like the mouth of the Mississippi, Straits of Gibraltar, English Channel, etc) you had to reduce the AIS range down 10 miles or less, otherwise you would get hundreds of targets - which was too much information to deal with.

The greatest advantage AIS gave to me was the ability to directly call a ship by it's name instead of like in the old days "calling the purple freighter heading south 20 miles from Malta...). You could throw in their lat & long, but that usually didn't help out much!

Overall, AIS helped greatly with direct communications to the nearby ship, but didn't prevent collisions - that still came down to radars and the vhf and the officer on watch.

I have one on my sailboat, but it is receive only. I always get out of the way of big ships - solves all the problems.

[01kiwijohn]

In the ocean, and coastal waters, at night, I set the CPA alarm, works wonders when the 'on watch' is not quite 'on watch!'

[neophytecruiser]

Just a minor correction, U.S. military vessels do have AIS capabilities but only use them when entering or departing a port. I found it interesting that a submarine that had surfaced beyond the entrance sea buoy to San Diego bay showed an icon on the Vesper AIS as a circle with a cross in the middle of it. All the small security escort vessels showed as the normal boat-shaped icons.

[FP38]

just seen this boat in the west indies

KATARA - Yacht: current position and details | IMO 9562805, MMSI 466066000, Callsign A7WD | Registered in Qatar - AIS Marine Traffic

[Mike OReilly]

So far, I'm another happy receive-only AIS users. I understand the benefits of being seen, but I don't feel the need to transmit my personal data (location, and all that goes with an MMSI file) for all the world to see. Collision avoidance is MY responsibility, so I'll take the additional info and capabilities AIS affords me, and continue to avoid hitting, and getting hit.

BTW, it's no surprise that most responders so far have indicated that the receive functions, and the ability to make quick and direct contact with potential targets, is the most valuable part of AIS for cruising vessels. I concur .

Question: How big an improvement has their been in small vessel collision rates due to AIS? We now have over a decade of data available. Surely someone has done the study.

[FamilyVan]

Originally Posted by SailFastTri

The reason to want one is because you want to be noticed by others (for your own safety) and there's nothing to fart around with... Just an on/off switch. If you're planning to operate in dangerous waters and want to be stealthy, there's another switch to disable transmit but still receive. That's about all the "farting around" you can do with AIS.

In limited visibility I want others to know I'm there, so faster/bigger and any other vessels can avoid me.


edit: And confined/congested waters is where you're most likely to have a collision, so yes there too.

I agree, limited visibility is a circumstance I'm very happy to have mine. But in heavily congested and confined waters they're darn near useless, either you have your alarm off, or its going off continuously and distracting you from driving the boat.

Sent from my XP7700 using Cruisers Sailing Forum mobile app

[Cadence]

Originally Posted by yttrill

Military vessels typically do not use AIS. They have their own systems. USCG is military. They may opt to switch on their transponders when involved in search and rescue and keep them off at other times.

Probably more during drug enforcement by the CG. Here I am avoid me.

[tdoster]

Our AIS is on all of the time, even at the dock. I find it is both a security and safety device. The rules are obviously different if in another country or far offshore, but cruising in the US, Canada and Bahamas:

1. When you are a couple hundred miles from your boat, it is nice to go to any of the AIS internet sites and see your boat, as well as a track. If you have to leave it and fly home, or from home. This is especially nice when anchored as it shows up on your smartphone when on shore. As more repeating stations are put in and technology catches up, you essentially have an anchor watch away from the boat and LoJack built in.

2. It is on when out, even on a clear day. If something happens, there is a last known position when sailing in coastal waters. Family at home can see where I am when single-handing. This would not be a good thing if your last name is Kennedy and the name of your boat is Monkey Business, but works for me.

3. I actually believe the CG leaves you alone more as they know exactly who you are and where you are going, and if you are willing to broadcast then you probably have less to hide. Jury is still out, but it may cut down on the number of boardings. So far, so good.

4. In congested waters, the alarm gets turned off, but it really does help with overall situational awareness even on clear days. I can easily time passing and crossing channels with the traffic, so less nail biting when coming up to a busy intersection. Less visual estimation of speeds or over compensating course corrections passing ships. Also, it has proven it's worth in timing tugs following or ahead. How much to speed up or slow down to make the most of your time and not get stuck behind for any longer than possible. Also to time to follow one through a lock, or bridge opening, etc. And most important to speed up or slow down long before meeting them at the narrows or turns or even getting stuck behind one for any longer than possible only to have him forcing you to push it harder a few miles down when he hits his speed again. Neither of us are surprised when meeting on a blind narrow, as he is anticipating me as much as I am anticipating him. If he needs more time and room, he is more likely to hail me long before we get to a point of being shoved up on the banks.

5. It makes GICW much less stressful for the obvious reasons, and I have actually found that the tugs will share more of the ICW with you when you are both tracking on AIS. Also, it is easier to get a tug to answer you on the radio when you call them by name. If they fail to answer a hail and run you aground and you have AIS, you have something to back up your claims as you call the CG who can review the radio transmissions and AIS tracks.

6. At anchor at night, it is on and calculated in my power requirements. Just a ton more reasons to have it on, then leave it off.

7. I am totally against over reaching, but I am fine if it were a requirement for all boats in navigable waters to be required to transmit. I have yet to see congestion in any port that would be worse than looking at a squawk overlay for ATC or in larger aircraft with the collision avoidance. At least we are all parallel to each other.

Bad guys will normally be the ones trying to fly under the radar, so maybe the CG would spend less time on honest AIS targets and more time on unknown radar targets.

It does put a bite in racing confusion tactics, like the old toilet paper trick over the stern light, but most of the time, radar becomes a tactical tool anyway.

[DMCantor]

We had the experience of a BIG sea-floor exploration vessel a) calling us on the VHF and telling us to stand on, he would alter course to avoid us and b) thanking us for having AIS so he could tell what the situation was. That one example made AIS a must-have for us.

[svseawitch]

AIS receivers are cheap. AIS transmitters are costly. Lots of boats are receive only. Hard to tell how many actually have transmit capability and don't turn it on.










From Marina Del Rey to Catalina you don't really need AIS but we do leave it on.


Recently, we've noticed that the ships are calling us and letting us know what their intentions are. Makes it easy to avoid them. Strong incentive to remember to turn it on.




Some boats may choose not to turn it on for privacy. Their wives can use the internet to track them. Not more excuses for being late getting home. Having AIS makes it harder to impress your friends as to how fast you are sailing. AIS eliminates the exaggeration :-) And some folks just don't want to have to talk on the radio. Leaving it off means nobody knows you are there