Considering AIS on a budget

[sanibel sailor]

I am considering adding AIS to my very simple electronics. I would like to maintain a tight budget. My Raymarine plotter is the RC435 that I understand does not accept AIS input. I will run OpenCPN on a laptop to view AIS info. To give you an idea of my sophistication, I dread trying to connect this thing to the laptop. I know the sky is the limit in terms of capability if money is no concern, but it is.
I am located in SW Florida where there is hardly any commercial traffic so seatrialing will be limited but hope to venture further afield in the next few months.



Not sure if I want just the receiver or also a Class B transceiver. Don't think there is much value to me in the added SOTDMA features.

I have a basic VHF with the common masthead stainless whip antenna.
I also have a spare whip antenna that I could mount on the sternrail.


If I just get a basic receiver for a couple of hundred dollars, I can use a cheap $35 splitter and use the masthead antenna, keeping the sternrail slightly more free of clutter and giving good range.



I am also considering the Em-trak B-300 transceiver. Built in GPS saves me one more external gizmo. Would require either a fancy splitter for another couple of hundred or use of the sternrail antenna that would reduce range, significantly mitigating some of the advantages of AIS transmission. I could stage it with the splitter added later if performance is unsatisfactory.



My questions-
1) How much range is lost -in practice- with a sternrail mount antenna? I feel I don't really need to see ships that are over the horizon and not headed towards me. Of course, for the ones headed towards me, I would like as much notice as possible.

2) While I understand the theoretical advantages of broadcasting my AIS info, how useful is it in practice? I imagine AIS may have reduced ships' watchkeeping with computerization giving the watchkeeper an alarm for vessels that will approach within a certain range. If so, I will need to be more diligent about my watchkeeping if I am not transmitting.

[Pete7]

We have the slightly older B100 from Em Trak. I don't know how far we transmit yet, but with this and the previous receive only AIS we could see ships between 7 and 10 miles. The antenna is mounted on a S/S pole on the transom so the top is perhaps 4m above the water. In 12 years never had a problem or really wanted more range. It's the nearest crocodile to the canoe I tend to worry about first.

Useful? very and I wouldn't be without it.

Pete

[CarlF]

Get a transceiver. Just a receiver leaves out the most important part of AIS - that commercial ships will see you on their primary anti-collision system.

Little white fiberglass sailboats were never that visible from 80ft up on a 800ft ship going 20 knots. And the radar return was worse - easy to mistake for birds or waves. I haven't had anxioius moment with a large ship since I started transmitting AIS.

You'll also find that ships will respond more often to VFH hails since they can see your name right on their screen. And surprisingly often, they'll hail you by name.

And finally, it's just plain considerate to transmit for your fellow sailors who have AIS. Being able to see the closest approach (CPA) to other boats makes my navigation much less stressful. I spent 40 years asking my wife "Can you tell if the bearing is changing?". Now I know with a glance.

To your other question, the stern rail will be just fine. It's more important to have a good SNR from quality Coax and properly soldered end fittings. AIS signals are weak. If you aren't really good at soldering consider the Shakespeare solder-less ones. They test very well and are just about foolproof.

I do have a Vesper splitter. It's one of the best with its own amplifier but is $200 - so may be out of your price range. With it and a masthead antenna I do get 50NM range with is of no real value. But I believe the greater height also really helps on Class B transmit range. I occasionally don't see a small boats AIS until 3 miles. I've confirmed by VHF that I'm reliably visible at 8 miles. There's a big difference if the other guy is a container ship going 20 knots.

[JPA Cate]

@sanibelsailor,

When we had class B receive only, I was content with that. Having it will not change your watch keeping processes very much. Those ways have kept you safe for some while.

It helps some times to have the ships' names when they are far off where we cruise. It is rare that we hail them, but giving them extra time to avoid us is good. We often find ourselves offshore among them, and it is useful for them to "see" our AIS, and so we bought a transmitting one anyhow. They do a great job avoiding us. [A couple of years ago, Dockhead had a thread wherein he described how a ship could suck a sailboat to it--dam scary. Anyhow, I like some space between us and them.] We and they are going opposite directions, and the closing speeds are fairly high. Still, the sailboat is more nimble than the merchant vessel, and you just stay the heck out of his way.

I think you'll be okay with receive only. But, we have a friend who had the transmitting AIS Class B, and he told Jim that he'd want a transmitting one, just wait, he himself loved his. About 3 years later, we got the transmitting one, and Jim likes it very much. Maybe he'll come along and explain clearly why.

Ann

[Pitchondesign]

So some extent it depends on where you go. SW doesn't have much commercial traffic as you know. Most of the Bahamas doesn't have much commercial traffic except Freeport and Nassau. We had receive only for years and it met 95% of our needs. One night we were transiting the Freeport area with over 20 AIS contacts, all ships. The cruise ships were moving at 20+ knts, freighter and tankers were either drifting or moving slowly. At one point we had predicted CPA of less than 1,000' on three ships at the same time. Those three ships planned where they were going, but I don't think they saw us. We dodged all of them, but it wasn't fun. We did raise the cruise ship on VHF because we had the name of the ship and it did change course. After that we got a transceiver. But, we managed to stay safe because we could call ships with a specific name. If there is any question whether a ship can see you, you merely make a VHF call, as long as you know the name of this ship which AIS receive gives you. Our experience is ships always respond to a radio call if you identify them by name.

Once again, it depends on where you go. If you are transiting near commerical traffic regularly, you need a tranceiver, radio calls are too cumbersome. If you rarely go near commercial traffic, receive only will be fine.

[Bill O]

Originally Posted by sanibel sailor

I am considering adding AIS to my very simple electronics. I would like to maintain a tight budget. My Raymarine plotter is the RC435 that I understand does not accept AIS input. I will run OpenCPN on a laptop to view AIS info. To give you an idea of my sophistication, I dread trying to connect this thing to the laptop. I know the sky is the limit in terms of capability if money is no concern, but it is.
I am located in SW Florida where there is hardly any commercial traffic so seatrialing will be limited but hope to venture further afield in the next few months.



Not sure if I want just the receiver or also a Class B transceiver. Don't think there is much value to me in the added SOTDMA features.

I have a basic VHF with the common masthead stainless whip antenna.
I also have a spare whip antenna that I could mount on the sternrail.


If I just get a basic receiver for a couple of hundred dollars, I can use a cheap $35 splitter and use the masthead antenna, keeping the sternrail slightly more free of clutter and giving good range.



I am also considering the Em-trak B-300 transceiver. Built in GPS saves me one more external gizmo. Would require either a fancy splitter for another couple of hundred or use of the sternrail antenna that would reduce range, significantly mitigating some of the advantages of AIS transmission. I could stage it with the splitter added later if performance is unsatisfactory.



My questions-
1) How much range is lost -in practice- with a sternrail mount antenna? I feel I don't really need to see ships that are over the horizon and not headed towards me. Of course, for the ones headed towards me, I would like as much notice as possible.

2) While I understand the theoretical advantages of broadcasting my AIS info, how useful is it in practice? I imagine AIS may have reduced ships' watchkeeping with computerization giving the watchkeeper an alarm for vessels that will approach within a certain range. If so, I will need to be more diligent about my watchkeeping if I am not transmitting.

John,
If you just want AIS receive then have about a upgrading your vhf w/gps and AIS. This Standard Horizon gx2200 is ~$300 has AIS, GPS and DSC. Best thing you can use you old vhf antenna w/no splitter and with a USB RS232 cable you can hook it up to your computer for overlay on OCPN like this. (The USB RS232 cable can be purchased other places than Milltech.)

This is how we hooked up our nav. computer using a raspberry pi as a main computer as a base computer which can wifi/wireless send data to the computer we use in the cockpit. This may be more than you want, but it does work well to replace old electronic w/o breaking the bank.

[sanibel sailor]

I looked at the GX2200 first as an all-in-one solution. But the guy at West Marine suggested Em-Trak which surprised me a bit as they don't carry it. The screen on the GX2200 is tiny and I understand has readability issues, but could be OK for hooking to the laptop. That VHF is about $400 so not much savings.


My current VHF does have DSC and ability for GPS input (which I have not hooked up)

[Bill O]

The link I sent was $299 now. You may be able to find it cheaper somewhere else.
This is what we have hooked up to the nav station computer for AIS and the GPS built into the radio is our secondary GPS if the primary GPS drops out.
Yes, the screen on the radio is small, but it is an easy set up to run the cable to view it in ocpn and no splitter needed for the antenna.

[thomm225]

Originally Posted by sanibel sailor

I looked at the GX2200 first as an all-in-one solution. But the guy at West Marine suggested Em-Trak which surprised me a bit as they don't carry it. The screen on the GX2200 is tiny and I understand has readability issues, but could be OK for hooking to the laptop. That VHF is about $400 so not much savings.


My current VHF does have DSC and ability for GPS input (which I have not hooked up)

As I already had the SH GX2200, displaying AIS/GPS on a monitor/HDTV cost me $5.00 for the 422/485 USB adapter, $90 for a Raspberry PI 4 computer (I could have used a $30 Raspberry PI 2B) and then I bought a 19" HDTV for the display for $65 which I will also use as a TV

I rarely look at the GX2200 screen except for the radio channel and maybe GPS

You can click on any of those AIS targets and get really good detail (SOG, COG, Home Port).....the display is Open CPN with AIS / GPS data showing my boat at the marina and the AIS Targets as far as 25 miles out

I also bought a GPS dongle as backup and a spare Raspberry PI and several spare adapters

[Reefmagnet]

I'd go with a new VHF transceiver with AIS reception. The reason being that by the time you add an extra antenna or antenna splitter you're probably going to be spending much the same amount. If you can pick up a NMEA 0183 version, it should be cheap and is easy to interface into a PC with an USB RS422 converter that can be purchased online for a few dollars. If you already have the antenna or want to play around with additional capabilities than a rPI 3 or 4 with AIS HAT is probably the cheapest stand alone option which will also provide the facility to transmit the NMEA data over wifi.

[Pegu Club]

From my experience with have a receiver only, I would say go transceiver. Its a one time cost and worth being seen when it is stormy rainy and dark out.

Fair winds,

[Tenedos]

AIS transceivers are very useful and I'd highly recommend. You are not only seen but other boats & ships know who you are as well. We sailed from San Francisco to Mexico and back last year, we were hailed a few of times by name at night by boats that we saw in radar but didn't know who they were (a pleasure boat called to ask for a port-to-pass passage at night, they never got closer to us than 2 miles, so that was a mystery. Anyway...). At all times, they could see us on their AIS receivers and knew who we were. AIS receivers are common, so even if you don't see them, they can see you and know who you are and where you are heading.

You can find a relatively cheap transceivers. If that is above budget and you decide to go for a receiver only, I'd recommend dAISy from Adrian Studer who is also a regular participant of this forum: https://shop.wegmatt.com/

[captmikem]

I bought this a while back and am very happy with it.

$132

It is not only an AIS it is a GPS. works wirelessly or wired.
It works on my Raymarine E-180, works on my Raspberry Pi, and works with my Garmin plotter.

simple and easy to hook up.

M

[pcmm]

For a receiver, you can't go wrong with a Dasiy 2+ they're $89 and work well. You can even make them wifi for a few$ more by getting a wifi card (DT-06) for about $6-7 on ebay.

https://shop.wegmatt.com/products/da...with-nmea-0183

they have an even cheaper one but its single channel

[meirriba]

Originally Posted by sanibel sailor

I am considering adding AIS to my very simple electronics. I would like to maintain a tight budget. My Raymarine plotter is the RC435 that I understand does not accept AIS input.

Not sure if I want just the receiver or also a Class B transceiver. Don't think there is much value to me in the added SOTDMA features.

My questions-
1) How much range is lost -in practice- with a sternrail mount antenna? I feel I don't really need
2) While I understand the theoretical advantages of broadcasting my AIS info, how useful is it in practice?

Are you sure you cannot connect AIS to your MFD? Seems strange as the MFD unit sits on NMEA net. Suggest to call RM to find out

I would strongly advice to have a transmitting unit! Great feeling when you call the tanker on your path and ask him "This is yacht XXX, do you see me on your starboard/port bow?"
They can't ignore such a call. Makes life easier, especially recogition by other crafts and arrange passing by in tight situations.

If you have an VHF you can use the radio antenna with a splitter for the AIS. Works fine from my experience.