AIS wanted on my Cape Dory 25D

[n5ama]

Originally Posted by Orion Jim

I’ve had the Garmin 800 for three years. They have gone back and forth as to whether a mushroom antenna is advised per my pro who made the installation. His advice is to go with the mushroom, which I have installed belowdecks. Since it was added performance has improved so I would consider it a necessary addition regardless of what the current installation instructions advise.
As a side note I have a Standard Horizon VHF (GX2400) which incorporates an AIS receiver. It is a stand alone as my preference is to have independent back up systems.

I have almost identical equipment with the Standard Horizon GX2200 and have the 800 coming. My Garmin 740S unit is a discontinued model of GPS/radar but it works well as long as Garmin continues to update the chart.

I'll definitely look into the mushroom antenna. Does the underdeck mounting bracket in the online installation instructions come with the antenna or is it a optional accessory?

Thanks

[n5ama]

Originally Posted by Donnybrook

n5ama, You might get more input by changing the subject to AIS wanted on my Garmin 740S as electronics integration is mostly independent of boat type...

Great suggestion. I guess I was thinking more boat and less specific equipment in case there was some advise saying that I needed to dump the Garmin 740S and change platforms.

Assuming I'll keep the 740S, it makes more sense to tailor my AIS question to that versus the boat.

Thanks for the guidance on structuring my query to get the information I need.

[Snore]

Originally Posted by n5ama

Wow thanks, This is my first time today to be called a idiot. I'm probably long overdue.

Sorry—- as a delivery Capt, drives me crazy when folks do stuff like that.

Earlier this year—- 150 NM off GA, I am stand-on to another sailboat. I try hailing, no reply. She had AIS off, suddenly it comes on, I hail her. She refused to give way as she “had to get east”. There was no one around!

So if I was unduly “cranky” my apologies.

[Nicholson58]

We chose Watchmate 850. It is totally stand alone but has a NMEA output to link data to a chart plotter. Stand alone means it works when everything else is off. It consumes 7.5 watts max as an anchor watch 24-7. It has its own B&W screen for identifying and plotting other vessels. Having a unit that only works through your other plotter means the plotter must be on, sucking down the amp hours.

[n5ama]

No apology necessary. I understand the problem and risks very well.

I'm located a few nautical miles west of the Houston ship channel and that in addition to the commercial traffic including a endless line of up to 1000' long barges on the ICW makes for a somewhat busy area.

I wouldn't go to the expense or trouble to install this equipment on my boat if I intended to shut it down, but in the very unlikely event I'm down to battery fumes and have to contact the USCG for help, I may "temporarily" shut down the 5w (every few seconds) AIS transmission long enough to make a call.

[n5ama]

Originally Posted by Nicholson58

We chose Watchmate 850. It is totally stand alone but has a NMEA output to link data to a chart plotter. Stand alone means it works when everything else is off. It consumes 7.5 watts max as an anchor watch 24-7. It has its own B&W screen for identifying and plotting other vessels. Having a unit that only works through your other plotter means the plotter must be on, sucking down the amp hours.

Sounds like a great feature to have. Does it run on a separate battery that can be charged with the rest?

[sailjumanji]

Vesper XB8000 with SP160 splitter and one of their AIS/VHF antennas on top of mast. NMEA 2000 so targets show up on your chartplotter via the network. Vesper is best in Class. Have used this setup on my last two boats for almost 8 years and never an issue. Splitter is fine, and theirs is powered so there is no loss. Don't need two antennas regardless if what naysayers say. Their Watchmate app is also an extremely good anchor drag program. The XB8000 also has wifi, so it will also send its own and other data to a tablet. You won't find dissatisfied Vesper owners.

[sailjumanji]

Originally Posted by n5ama

I'm located a few nautical miles west of the Houston ship channel and that in addition to the commercial traffic including a endless line of up to 1000' long barges on the ICW makes for a somewhat busy area.

We've done the ICW run from Kemah to Port Aransas a lot. Before we got AIS, it was always a struggle to contact tows as you needed to know statute mile or their name to hail. Once we installed transmit AIS, we had them calling us to establish passing protocol. Even had one suggest a stretch for us to overtake him.

[n5ama]

Originally Posted by sailjumanji

Vesper XB8000 with SP160 splitter and one of their AIS/VHF antennas on top of mast. NMEA 2000 so targets show up on your chartplotter via the network. Vesper is best in Class. Have used this setup on my last two boats for almost 8 years and never an issue. Splitter is fine, and theirs is powered so there is no loss. Don't need two antennas regardless if what naysayers say. Their Watchmate app is also an extremely good anchor drag program. The XB8000 also has wifi, so it will also send its own and other data to a tablet. You won't find dissatisfied Vesper owners.

Sounds great.
Do you think it will work with a generic VHF antenna such as the Shakespeare VHF antenna or does it need the Vesper unit to work both VHF and AIS frequencies? I see you can buy the unit with a splitter and the external GPS antenna. If it needs their VHF antenna means I have to climb the mast to change the existing antenna. Really don't want to do that unless its necessary.

I'm sure the splitter doesn't care but the transponder might choke with a SWR it doesn't like.

[slipaway]

I have the (discontinued) Garmin 740s; added the Standard Horizon GX2200 with GPS and AIS receive only. Works great. All the AIS info is displayed on the charplotter. There was no need for any changes to the antenna configurations; just had to run the new cables and connect to the chartplotter. I only have need for AIS receive (based on where and how I sail) so didn't want to add the transmit capability which does require the seperate unit and antenna (or splitter).

[CarlF]

In a relatively slow (but wonderful) boat like the Cape Dory 25d - the biggest benefit of AIS transceiver is that you don’t get run down by an 800ft freighter going 24 knots. You don’t always have the speed to get out of their way.

For commercial ships AIS is the primary anti-collision systems - much more now than radar. If you don’t show up on their AIS display, you are at a disadvantage.

A regular vhf antenna will work fine. Use a splitter - an AIS antenna at deck level may have only a 3 mile transmit range - not enough time for a big ship to avoid you.

[sailjumanji]

Generic antenna that works well and is tuned for the VHF, would probably still work satisfactory for the AIS. That's what I did originally, but then we swapped out a year later when we rerigged the boat.

[n5ama]

Originally Posted by sailjumanji

Generic antenna that works well and is tuned for the VHF, would probably still work satisfactory for the AIS. That's what I did originally, but then we swapped out a year later when we rerigged the boat.

I'll probably do the same but climbing the mast to replace a one year old antenna gives me the Hershey squirts. I was recently at the top when a helper stepped on the boat at the slip and it felt like I was going in the water before it recovered and straightened up.

[Jim Cate]

but in the very unlikely event I'm down to battery fumes and have to contact the USCG for help, I may "temporarily" shut down the 5w (every few seconds) AIS transmission long enough to make a call.

FWIW, the power used to make the AIS signal transmission is essentially zero... the two or five watts is only on for a few milliseconds for each transmission, and that's only every 30 seconds or so for the 2 watt system and a bit more often for the 5 watt models. It is the display and other bits that use the (rather miniscule) power... usually a total of a few watts average.

And for your application, a reasonably new standard VHF antenna at the masthead will work just fine...at least ours does, and has for several years now.

Jim

[thomm225]

Originally Posted by CarlF

In a relatively slow (but wonderful) boat like the Cape Dory 25d - the biggest benefit of AIS transceiver is that you don’t get run down by an 800ft freighter going 24 knots. You don’t always have the speed to get out of their way.

For commercial ships AIS is the primary anti-collision systems - much more now than radar. If you don’t show up on their AIS display, you are at a disadvantage.

A regular vhf antenna will work fine. Use a splitter - an AIS antenna at deck level may have only a 3 mile transmit range - not enough time for a big ship to avoid you.

If you have an AIS receiver though, you should be able to set your CPA alarm so you would know if a ship was for example within 5 miles of you. (depending on the range you decide)

My AIS info is received thru my old VHF antenna and I have received target info as far as 32 miles out.

You can set that CPA Alarm on your VHF (the SH GX2200 and above can) and don't even need anything else for that matter.....