AIS, Receiver or Transmitter

[Teknishn]

TJ D...Ya know, for an "arrogant guy" you make a lot of sense and it hasn't fallen on deaf ears. Retired Navy here. Didn't do helm watches very often, just enough to qualify as OOD as an enlisted onboard an oiler. Was an IC-man (the guys that had to take care of most of the electrical/electronic Nav gear...and learn how to use it). AIS was just coming in before I retired and it was a "kind of magic". So I understand you're coming from on both sides of the AIS discussion here (commercial and recreational). +1!

[uncle stinkybob]

Originally Posted by MarkJ

Weird how everyone basically agrees a transmitter is best until one person says "its a no brainer" and then a bunch of people say a transmitter isnt any good!

So I should just stop reading this thread... Instead I am posting to it

If now was then they wouldnt even have made receivers. They only did it because of luddites complaining about power consumption. But as we know its negligable and people have better electricity 10 years later.... But the companies can still sell the receive only box as it doesnt cost them anything and they make a profit because of the huge markup.


Transmitting. See the pic below. This is at 2 am in the Florida Straits, no VHF calls, all ships too far from me for me to have started to divert... And count the number that have diverted... 3. Note the red ring is 10 nm miles

This is a "no brainer" screenshot butI know there are some who will try some ******** so let me say soemthing to placate you: its a no brainer!



Lets sing all together... Its a nooooo braaaainerrrrrr...

but think of the money you could have saved. It makes 0 sense to me why anyone would but such a great safety device and decide only half is sufficient. Half brainers?

[DotDun]

Originally Posted by Mike OReilly

Yup .

You can get all moral about it if you like. But let me ask you, how many collisions did you have before AIS? How many since? In fact, if AIS is such a great benefit, and now that we've had many years of experience, please show me the data that demonstrates the vast improvement in collisions. I've looked, and can't find the evidence.

It's a tool. A useful tool. No one forces you to transmit, so thanks for doing so . I'm fine.

Not moral, as I stated earlier, it's simple arrogance to believe you don't need others to see you, but you want to see them.

Your double argument is interesting....no evidence of AIS usefulness, but you still find it useful, even using it half-assed!

[TJ D]

Originally Posted by Teknishn

TJ D...Ya know, for an "arrogant guy" you make a lot of sense and it hasn't fallen on deaf ears. Retired Navy here. Didn't do helm watches very often, just enough to qualify as OOD as an enlisted onboard an oiler. Was an IC-man (the guys that had to take care of most of the electrical/electronic Nav gear...and learn how to use it). AIS was just coming in before I retired and it was a "kind of magic". So I understand you're coming from on both sides of the AIS discussion here (commercial and recreational). +1!

Thanks, I was sort of shocked by the harsh reaction, to be honest, but such is the nature of the internet, I suppose.

I've got some pretty strong feelings about this system's contribution to safety, as you might have noticed. We spent the last 2 summers in Newfoundland in the fog most of the time, and man, what an invaluable tool. I had the opportunity to show a lot of local skippers who weren't using it our display, and I think that there will be quite a few converts over there.

ARPA is ok, yes, EBL's on the radar sort of work too, but in a seaway, these things just aren't that good on a small boat with our crappy little flux-gate (and they're all crappy compared to big ship gear) compasses feeding everything.

On my commercial vessel, we use both a GPS compass, and a $60,000 gyrocompass to try to get decent, stable, headings to our radars among other things, and even with this expensive gear, when things are really rough out, we have enough wandering of ARPA predictor vectors (not to mention a substantial lag when detecting the other vessel's course/speed), that it's FAR inferior to AIS. Ditto for our beloved hand bearing compasses, and whatever else is being used aboard to assess risk of collision.

Ok, I'll bow out now. I hope I've made the point clearly without offending anyone this time around.

TJ

[Mike OReilly]

Originally Posted by DotDun

Not moral, as I stated earlier, it's simple arrogance to believe you don't need others to see you, but you want to see them.



Your double argument is interesting....no evidence of AIS usefulness, but you still find it useful, even using it half-assed!

So, you are so arrogant (to use your colour word of the day) as to believe your way is the only way. We just went through this in another thread.

The OP asked for info. I provided my experience. If you can't tolerate someone being different than you, how on earth do you actually cruise to other places?


Why go fast, when you can go slow

[CarlF]

The budget argument is obviously real - but only fair if applied to other equipment too.

My radar is substantially more expensive and power hungry than an AIS transceiver. I use it more than most as I see frequent fog.

But if my budget (either money or amps) didn't allow me to own both, I would choose an AIS transceiver.

Carl

[wrwakefield]

Originally Posted by fishsail18

Is a transmitter really needed for a cruising couple on a 41' sailboat? I see the price for the transmitter was approx. 40% more than a receiver only. any major pros to go for the Receiver/Transmitter? I've heard some like to switch off the transmitter so they are not seen?
Thanks

Fishsail,

I've read this thread and now you see how divisive this topic can become.

We made a choice to transmit AIS 24/7 when not at a dock. [Side note- some choose to also Tx at a dock perhaps to track their vessel when away from it... We have a separate device that takes care of that for us, and both are dependent upon either cell data or WiFi.]

This means we always broadcast our position when at anchor, and feel this is very important given the remote areas we are exploring. I can cite many examples where this has paid off for us over the years.

At anchor we set a filter profile in the Vesper so we are not bothered with AIS alerts that don't matter to us at anchor, but are still alerted if our chosen proximity zone is violated. [RADAR is set up the same way too... If interested in more details about this and other measures we take at anchor, see our recent post 'Sleeping well at anchor'...]

And don't forget the benefits of the stellar anchor alarm functionality built-in to our Vesper AIS...

But unlike many boaters, we are currently playing in areas where the present satellites don't pick up our AIS signals, and shore AIS Rx stations are very infrequent.

On several occasions I've given some thought to whether I would feel differently about broadcasting our position 24/7 if we were in an area where our AIS was picked-up and broadcast on the internet most of the time. [Which it may be as new AIS Rx satellites are put into service...] The answer is no, I wouldn't stop broadcasting full time because we believe we aren't important enough for anyone to care about our whereabouts, and we are not fugitives from the law... yet anyways... <He said with a big grin...>

Important to us, since our POB alert beacons are presently AIS transmitters with GPS, we have 2 AIS receivers [for redundancy.] One built into our primary VHF, and that backs-up our Vesper Watchmate 850 AIS. We can select which AIS to use in our MFD, tablets, computers, etc. Therefore, both are receiving AIS full time and each is in active use on one or more devices [live redundancy.]

Does transmitting AIS pay off when others only choose to receive? Yes. A common example for us is when the fog sets in while transiting near or off- shore on the Alaskan or Canadian coast. We will sometimes be contacted by other recreational vessels letting us know they see us on AIS and if we hold our course or do this or that we will miss them. These are typically vessels with Rx AIS only. We cannot see them on AIS, nor usually RADAR, so we are at their mercy and judgement. But at least they made us aware of their presence because we were broadcasting our position on AIS. This is not as good as tracking them as they are us, but better that both being unaware of the other...

This type of encounter is like closing your eyes as you pass a car on the road at night with no headlights; you cannot react to anything that goes wrong on their end.

This makes us wonder how many don't contact us in such conditions.

And we are often contacted by cruise ships [originally typoed as cruise shops- which is perhaps more accurate...] and the like even in excellent conditions because we are transmitting AIS.

If you decide AIS Rx only is adequate for your current needs, getting a VHF with AIS Rx built-in is likely the best value.

Best wishes deciding what is best for your needs, and safe sailing to you.

Cheers! Bill

[DotDun]

Originally Posted by Mike OReilly

So, you are so arrogant (to use your colour word of the day) as to believe your way is the only way. We just went through this in another thread.

The OP asked for info. I provided my experience. If you can't tolerate someone being different than you, how on earth do you actually cruise to other places?


Why go fast, when you can go slow

I accept your choice, I don't accept your justification for your choice. To state that you don't want others to see you, or that others don't need to see you as you are fully capable of acting alone in the game of collision avoidance is ludicrous and arrogant.

Why not tell us the 'real' excuse: You can't or don't want to spend the $$ for a transceiver. That is the only reasonable excuse!

My statement about AIS receive-only units should have never been manufactured comes from the fact that those with receive-only capability hold off buying a transceiver as they believe they have 'enough' collision avoidance tools. Had receive-only capability not been available, a good majority may have put out the $$ for a transceiver.

In the effort of full disclosure to the OP, my goal is to explain that the AIS 'system' relies on transmissions and that having receive-only capability is actually detrimental to that 'system'.

[fishsail18]

Well MARKJ has won this debate as he brought a pic. to show and tell. And seeing I only have half a brain I will go with the data from the pic. The swigley lines moving out of his way tells the story I needed to hear. Thanks you all for yur opinions.
Now lets argue over something else.

[anacapaisland42]

Has anyone heard of:
dAISy Open Source AIS Receiver
I haven't seen anything posted about this so I thought I would.

A fellow named Adrian Studer has designed an open source AIS receiver and is selling them at a pretty low cost ($55). You can find them here on Tindie (recently back in stock)
https://www.tindie.com/products/astu...-ais-receiver/

Or you could find the sources and board layouts on github and build one yourself.

Here is an article of a boater using one with OpenCPN on linux (Raspberry Pi).
https://mvcesc.wordpress.com/2015/04...pi-2-with-ais/

[pcmm]

The problem with requiring everyone to have AIS tx is that it becomes useless. If you look at marinetraffic.com for singapore (an area that requires it) there are over 2600 listed tragets! that's to the point of becoming just "clutter" and not useful. Jamie on "Esper" also made the same observation that when he turned on his AIS overlay for his chartplotter, there were so many targets that it was useless. he had to filter out all but the "dangers" at that point you might as well just turn it off!

[Cap Erict3]

I too am in the "bought receive then upgraded to transmit" camp.

I didn't consider the $700 cost peanuts. I do like reliably showing up on the displays of out of sight vessels.

It took buying and using the rx only unit to prove the value of an AIS transceiver to me.

If you can afford it, get a receiver. Great tool.


Here's hoping that a low cost AIS tx/rx / vhf unit will hit the market soon.

[alaskaflyfish]

Originally Posted by DotDun

I accept your choice, I don't accept your justification for your choice. To state that you don't want others to see you, or that others don't need to see you as you are fully capable of acting alone in the game of collision avoidance is ludicrous and arrogant.

Why not tell us the 'real' excuse: You can't or don't want to spend the $$ for a transceiver. That is the only reasonable excuse!

My statement about AIS receive-only units should have never been manufactured comes from the fact that those with receive-only capability hold off buying a transceiver as they believe they have 'enough' collision avoidance tools. Had receive-only capability not been available, a good majority may have put out the $$ for a transceiver.

In the effort of full disclosure to the OP, my goal is to explain that the AIS 'system' relies on transmissions and that having receive-only capability is actually detrimental to that 'system'.

Your position imply s that visual contact is no longer the MOST important part of navigation/collision avoidance but instead AIS contact has become the replacement for visual separation. Personally, I feel visual separation maintains priority and AIS in any form is secondary. A useful tool, but unnecessary. How did people avoid collision before the advent of AIS? Yup, you guessed it, VISUAL. I choose not to have AIS, does that mean I am taking advantage of others generosity or paranoia? Please explain.

[leftbrainstuff]

Originally Posted by fishsail18

Is a transmitter really needed for a cruising couple on a 41' sailboat? I see the price for the transmitter was approx. 40% more than a receiver only. any major pros to go for the Receiver/Transmitter? I've heard some like to switch off the transmitter so they are not seen?
Thanks

We've just added AIS class B to our Liberty 458. Our decision was based on the advice of other AIS users on the forum.

Immediately after turning on our AIS for the first time the benefits are obvious. We can be seen and identified by others especially ferries and large ships. Very usefull up here in the Pacific North West. Secondly we can identify others by name making comms simple for local information requests.

We can see that very quickly AIS will become usefull everytime we sail. The same can't be said for radar, sonar, vhf and the myriad of other systems we have on board.

I have described AIS to others as like radar that sees around corners and it has a much better signal to noise ratio. (For transmitting vessels only)

I personally consider it very good value for money. If you amortize it per usage the cost is much more attractive than other systems. It's one of the few safety critical systems that you can use regularly.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

[holmek]

I'll start off by saying that I'm not sure of my facts, - But is there not a difference in transmit power or frequency or something like that and the ships can choose to "switch off" small AIS transmitter's incoming signals so as not to have to bother with us small fry?