Nasa AIS
- Thread starter rosewood
- Start date
prv
Well-Known Member
pvb
Well-Known Member
I'm just casting my mind back to the posts years ago when I was criticised for suggesting that fitting an AIS transponder was, for many leisure boats, a bad move as it would result in so much Class B clutter on ships' screens that they'd simply turn off Class B. Now it's happened, and it's the leisure boats that are turning off AIS because of the clutter. Delicious irony.
maby
Well-Known Member
I'm not sure that is true - a good AIS setup will take into account the rate of turn data in the message to predict a collision that is not immediately obvious.
I have to say that my primary interest in AIS is getting the MMSI of a ship to check their intentions - putting out a call on channel 16 for "effing big green cargo vessel two miles behind me..." seldom produces an answer.
prv
Well-Known Member
I'm not turning off because of the clutter; the Vesper copes reasonably well with that. It's just that I don't see any need for AIS in the Solent. The ships travel up and down a well-defined track, one at a time, at a relatively slow speed; it's easy to make sure you're not in their way. And you need to be always on the ball for other leisure vessels, ferries, etc, so the AIS's benefit of keeping a constant lookout all day over a boring sea isn't needed. And there's no point in the ability to see over the horizon, because in most directions that's on land!
Pete
rosewood
Well-Known Member
Thanks for all the replies. Still not sure what to do though. Will have a another read and a think
VicMallows
Well-Known Member
Quite agree. Is there ANY leisure market equipment yet that allows Class B to be filtered out? It should be a simple change to something like OpenCPN or SeaClear but the 'powers-that-be' seem disinclined. Maybe there is a perceived liability issue if you deliberately exclude AIS data which 'could' be important? ..... obviously ridiculous if it then results in you turning AIS off altogether.
GHA
Well-Known Member
I have a nasa standalone, nasa engine into a computer running Opencpn and shortly to have a gx2100! 3 onboard might be a bit overkill, but the standalone will stay, it draws a tiny amount of power and works to well below 11v. Suppose it depends a lot on your boat and type of sailing but a bit off the beaten track I find it too useful to risk loosing it to flat(ish) batteries.
Scomber
Well-Known Member
me too- and-if the plotter packs up youve still got ais
pvb
Well-Known Member
Errr... as long as you have an alternative source of GPS data...
johnphilip
Well-Known Member
We started with a NASA display AIS but when we fitted a plotter fitted the AIS engine to display on the plotter at the binnacle instead. In practice with so much info on the plotter we found we missed the dedicated info on the NASA Screen. We reinstated this NASA screen and find both useful. Watching shipping on the AIS in a shipping lane requires more attention than the helm readily copes with. With the NASA also at the chart table the crew is able to monitor the position.
I am pleased to have both. (they share an aerial)
prv
Well-Known Member
I do
(My gx2100, Vesper display, and BR355 GPS puck form a self-contained VHF+AIS system with no reliance on anything else.)
Pete
Simondjuk
Well-Known Member
AIS on the CP180 works reasonably well despite the clumsy alarm logic if you use it where you need it, which is in open water. Entering a harbour or the Solent, I just switch the alarms off.
I managed to connect my 180 so that it shows depth, wind, speed and temp graphs, and to AIS from a 2100e and the autopilot, so there are sufficient ports. That said the graph data comes via a Raymarine bridge, which effectively adds a port, but is needed to turn the SeaTalk data into NMEA for the plotter. Wouldn't have bought it specially but thought I'd use it since it had become redundant elsewhere on the boat.
Connections were as per this very rough sketch,
Looking at it now, I'm not actually sure that all the connections I made are necessary. I can see two, one or the other of which may be superfluous, but it all works as it is anyway.
I managed to connect my 180 so that it shows depth, wind, speed and temp graphs, and to AIS from a 2100e and the autopilot, so there are sufficient ports. That said the graph data comes via a Raymarine bridge, which effectively adds a port, but is needed to turn the SeaTalk data into NMEA for the plotter. Wouldn't have bought it specially but thought I'd use it since it had become redundant elsewhere on the boat.
Connections were as per this very rough sketch,
Looking at it now, I'm not actually sure that all the connections I made are necessary. I can see two, one or the other of which may be superfluous, but it all works as it is anyway.
Last edited:
blackbeard
Well-Known Member
I have a NASA standalone; display is above chart table, can't put it in cockpit as display unit is (from memory, so may be mistaken) not waterproof.
might be worth checking to see if this is still the case (as it were) with current units. Apart from that, is fine.
might be worth checking to see if this is still the case (as it were) with current units. Apart from that, is fine.
alanwilson
Well-Known Member
I had a NASA AIS display for some time: it worked OK, but did seem to have a not very good range (separate aerial - definitely best - mounted on top of the mizzen mast, so good height of "eye").
Then was tempted by a Digital Yacht AIS engine, which displays on my chart plotter (using the same aerial): immediately double the number of targets shown. I navigated from Harwich to Southampton with the NASA, bought the Digital Yacht at the boat show & navigated back with it, so was able to do a good comparison.
The main problem is that the NASA AIS is single channel, while the Digital Yacht is dual channel: AIS transmissions are on either channel, so even if the NASA is set to alternate between the channels, you have a good chance of missing signals.
So I'd definitely go for a dual channel AIS which will display on your chart plotter. The display on a VHF is too small to be any use. You can get splitters so you can connect the AIS to the same aerial as the VHF, but they will reduce the signal strength and can't receive both signals at the same time, or when you are transmitting: get a separate aerial.
Then was tempted by a Digital Yacht AIS engine, which displays on my chart plotter (using the same aerial): immediately double the number of targets shown. I navigated from Harwich to Southampton with the NASA, bought the Digital Yacht at the boat show & navigated back with it, so was able to do a good comparison.
The main problem is that the NASA AIS is single channel, while the Digital Yacht is dual channel: AIS transmissions are on either channel, so even if the NASA is set to alternate between the channels, you have a good chance of missing signals.
So I'd definitely go for a dual channel AIS which will display on your chart plotter. The display on a VHF is too small to be any use. You can get splitters so you can connect the AIS to the same aerial as the VHF, but they will reduce the signal strength and can't receive both signals at the same time, or when you are transmitting: get a separate aerial.
BrianH
Well-Known Member
+1.
There is no excuse for single channel AIS receiver these days, even with a minor price advantage - and it is minor, check out the Advansea RX-100.
My single channel unit can take up to 12 minutes to synchronise with the static sentence (every 6 minutes) to obtain the ship's name - useful if you need to call up one heading straight at you. It's planned for replacement any time soon.