Receive only AIS Vs full AIS

[Nwdiver]

I am aware of the difference between a full and receive only AIS, but I am curious what the practical usage of the transmission version is, I know it allows others to see your location but in low visibility is seeing everyone else enough? The reason I ask is because the c288 has a Garmin radio that has an optional AIS model available. Just swapping out a radio is a much easier install then adding a full transmit/receive system

 

[Diatom]

Three thoughts favoring TX function:
1. Ganges Harbour - a CG hovercraft on a medevac night mission took out a someone's bowsprit a few weeks back.
2. Family knows where I am when I'm solo, tracks me on MarineTraffic. Potential life saver.
3. Active Pass - BC Ferry traffic - they see/ID me with certainty. Radar doesn't see around corners.

/tmm

 

[dbsea]

I think it's an additional aid in poor weather conditions and helps validate data that you might already have. I really like the transmit option in my boat, because that way I know when someone's looking at their radar / ais, they will not only see the blob, but also the AIS marker associated with my boat, and they are more likely to know I'm there and do their part to avoid. I also appreciate seeing this on my radar / chartplotter. Coming out of Gig Harbor yesterday the fog was like pea soup, and it was very helpful to see the radar blobs + AIS markers for the boats that were also in the channel.

 

[S. Todd]

I am sure no one on this site would ever be accused of doing so, but I find it extremely annoying when boats sit in their slips tied up securely still transmitting their AIS signals. Surely turning them off is not that difficult.

 

[dbsea]

I am sure no one on this site would ever be accused of doing so, but I find it extremely annoying when boats sit in their slips tied up securely still transmitting their AIS signals. Surely turning them off is not that difficult.

I'm definitely guilty of this. I am actually not sure how to turn the AIS transmit off on my AIS device (Garmin 600). I believe it is hard wired to power, and there's no switch. I actually appreciate having it on, so i can always see that my boat is where it's supposed to be. :-D

 

[FlyMeAway]

I am sure no one on this site would ever be accused of doing so, but I find it extremely annoying when boats sit in their slips tied up securely still transmitting their AIS signals. Surely turning them off is not that difficult.

For those of us with integrated AIS/monitoring, it's actually more than kind of a pain.

Additionally, most AIS install instructions recommend putting it on an "always on" 24/7 circuit, not on a switch or breaker. I never did get around to installing AIS on the sailboat I once had, but every bid had it wired with a fuse directly to the battery (whereas all other on-board equipment except the bilge pumps were wired through a panel and switch).

 

[Nwdiver]

I am sure no one on this site would ever be accused of doing so, but I find it extremely annoying when boats sit in their slips tied up securely still transmitting their AIS signals. Surely turning them off is not that difficult.

Actually it’s even more annoying to watch their boats cruising at 55mph several miles inland

 

[FlyMeAway]

Actually it’s even more annoying to watch their boats cruising at 55mph several miles inland

I couldn't find it just now but a few years ago I remember a YouTube video of an AIS "collision alert" involving a boat being towed on a bridge and another boat going under it 😀

 

[Rocky]

I added a Garmin AIS 600 to my R 29 a couple years ago. Frankly, the installation was more straightforward than you can expect with any marine electronics. the entire install was about 3 hours.... i did have to wait for an extension cable, so I didn't finish it in a day - but it was not a difficult instaIl.
I do enjoy knowing that AIS receiver only boats can see me.
As mentioned before, being able to be followed by family and friends is certainly fun.
When meeting up with other boats, they can see where you are either on AIS or the Marine Traffic App ( and vice versa if equipped).
I have been hailed -by name- by other boats (and WA Ferries) to determine what my plans were.
I am also guilty of my AIS transmitting from my slip - this told me once when my battery ran completely dead - my bad.
I have a switch that will turn on a "hide" function. No transmit while still receiving - (in case I need to smuggle drugs to support my boat habit 😀.)

For me, the price of the hardware and install was worth the effort.

I hope that helps.

Rocky

 

[CaspersCruiser]

…… I am curious what the practical usage of the transmission version is, I know it allows others to see your location but in low visibility is seeing everyone else enough?……

So, what about the other boat with receive only AIS that you meet in low visibility? You won’t see them and they won’t see you.

 

[Nwdiver]

Radar

 

[Martin610]

Having transmit AIS capability is definitely worth it to me. I sometimes fish/cruise near the port of New York. We get some really big vessels in some narrow channels, especially around Sandy Hook. Big ships can have a larger radar donut where they can't see you on radar if you're close, but they can pick up the AIS signal.

-martn610

 

[knotflying]

I am aware of the difference between a full and receive only AIS, but I am curious what the practical usage of the transmission version is, I know it allows others to see your location but in low visibility is seeing everyone else enough? The reason I ask is because the c288 has a Garmin radio that has an optional AIS model available. Just swapping out a radio is a much easier install then adding a full transmit/receive system

There are differing opinions on this and it will all boil down to your choice. I bought and installed receive only. I used it primarily on the river systems to see and to be able to communicate with the large barge tows so they could tell me where they wanted me to be. I also used it in the PNW to see the large ferries to get out of their way. Basically for use in high commercial traffic areas to see, avoid and communicate. While cruising among recreational boats I found it a nuisance and turned it off. I do not know why a large cruiser at dock needs to keep the AIS transmitting and I get constant warning alarms! Also, unless everyone is using AIS transmit and receive then it is a false sense of security. Radar would be a better means to see a target on open water than AIS. For my money, AIS receive accomplished my needs. A large commercial vessel coming at you cannot maneuver quickly enough to avoid you. Your obligation is to get out of their way. If you are dead in the water and they have AIS, as they should, you will see them and then you can tell them you can't move. At that point just pray that they can avoid you. My two cents.

 

[Oh Well]

Call me a safety freak. My Ranger 27 OB came with an AIS 300 (send only since discontinued as I understand). Thought it was send and receive. Had it changed out. Yes good to see others coming at you but better they can also see you. Simple to change the range if gets too annoying.

Oh Well!!

 

[SJI Sailor]

As for AIS automatic alerts, I don't see them as a problem ... because I turn them off. They are mostly just an annoyance in busy waters.

As for broadcast, I like it both for visibility and for monitoring. I think the argument for it is quite easy: if you like seeing others on AIS then you can expect that they would like to see you. Thus it makes sense for everyone to broadcast.

 

[FlyMeAway]

Having transmit AIS capability is definitely worth it to me. I sometimes fish/cruise near the port of New York. We get some really big vessels in some narrow channels, especially around Sandy Hook. Big ships can have a larger radar donut where they can't see you on radar if you're close, but they can pick up the AIS signal.

It isn't just the radar donut. With AIS and appropriately configured DSC, they can hail you directly. A large commercial vessel in a traffic lane can hail you and let you know they are turning into port and you're about to block their path.

 

[CaspersCruiser]

Radar

So why have AIS at all?

 

[SJI Sailor]

For one, fiberglass boats can have a very small radar profile, easy to miss, and radar is easily obscured by sea state or straight line obstacles. Another is that AIS shares more information such as speed, vessel class, name for hailing, etc. Between the two, radar is much more important though.

 

[FlyMeAway]

fiberglass boats can have a very small radar profile, easy to miss, and radar is easily obscured by sea state or straight line obstacles

Agreed, especially on powerboats. On moderately sized sailboats, it's easy to hang an effective radar reflector ~30' above the waterline. Not so on our boats.

The other thing to remember is that other boats (especially commercial vessels) use AIS for automated collision alerts in a way they don't with radar. MARPA is good, but it is prone to false alarms and requires much more human intervention / monitoring to do well than AIS systems do. The "automatic" part is not as reliable as AIS.

 

[Red Raven]

Perhaps a different point of view…

We went several years with only AIS receive. Pretty much not a concern for the above reasons. However, during multiple trips, we found AiS transmit could have been very useful when traveling with other buddy boaters.

- On one trip our buddy boat got well out in front with only a rough course plan for the day. We lost them when they got out of VHF range! We also had no mobIle phone connection. After an hour or two (!!!) we connected back up with some luck. They were on another course! At that point I realized that if we both had AIS transmit it would have been a non issue. While AIS transmit does rely on your VHF signal quality, as long as you are within range of any local VHF receiver that can repeat the signal to another you can pick it up.

- Also, when traveling with another boat we prefer to match our speed so we don’t constantly have to adjust throttle to follow. While radar (and the vhf radio!) can also give you this info (with a little effort) it is pretty convenient to just match the AIS speed of your buddy boat if available.

For these reasons alone I added the Garmin AIS800 to our boat. Pretty much plug and play for less than one boat unit (<$1000). Pretty handy! A benefit is that other boaters we know see us at a distance and often say hi! 😀

Worth it just for the convenience!

Curt