AIS transponder

[Daydream believer]

As a single handed sailor I have recently had some rather startling near misses.
The last one where i came withing 60 feet of being run down in the Black Deep by a large container ship that did not see me, nor I them ( How on earth can one miss 2000 containers coming at me - don't ask) has me worried

I need the equipment on deck & do not have time to go below in rough weather or fog to read instruments be they radar or AIS or whatever
My yacht is 31 feet & there is little room for anything so it will have to go in a box on the pushpit where I can see it from the tiller

I think that I need an AIS transponder so others see me as much as I can see them

My question is :-
Should I be looking at class B or class A ?

 

[pvb]

As a single handed sailor I have recently had some rather startling near misses.
The last one where i came withing 60 feet of being run down in the Black Deep by a large container ship that did not see me, nor I them ( How on earth can one miss 2000 containers coming at me - don't ask) has me worried

I need the equipment on deck & do not have time to go below in rough weather or fog to read instruments be they radar or AIS or whatever
My yacht is 31 feet & there is little room for anything so it will have to go in a box on the pushpit where I can see it from the tiller

I think that I need an AIS transponder so others see me as much as I can see them

My question is :-
Should I be looking at class B or class A ?

Class A is for ships! Are you running around Black Deep in a ship?

 

[prv]

Class A is for ships!

Doesn't have to be.

Pete

 

[davidwf]

I suspect they did see you but their ARPA may well have plotted a course quite close to you mind you 60ft is seriously close.

I presume you have a Radar Reflector? if not that's where I would start.

Apart from that an AIS receiver is good option, and a transponder even better for limited visibility, you would normally fit a class B transponder.

What about putting the plotter to display AIS etc. on a board that slots into the washboard slots or a swing arm I used a RAM mount on my previous boats which worked well.

 

[prv]

Personally (as I've said before) I would go with a radar target enhancer (Sea-Me or Echomax) before an AIS transmitter. All ships will be using radar, not all will be effectively using AIS (the number with integrated ECDIS or a useful AIS display prominently mounted is presumably increasing, but it only takes one...). An AIS receiver is always helpful.

If you do go with AIS, I would recommend the Vesper Watchmate series for their very useable display software.

Pete

 

[ShinyShoe]

Class A was the original and was designed for ships. Expect to pay over £1k.

Class B was designed for people without multi-million pound cargo. Expect to pay £500 +

Class B only transmits at 2W and has a range of 5-10miles transmit. If you were travelling in a power boat at 50kn that means you might only appear on a big ship's AIS for 6 minutes and if there were two vessels travelling on a head on collision course at 50kn they'd get just 3minutes warning.

I'm guessing you are more likely to be travelling at 5-10kn so you are going to normally appear at least 30minutes away. Even if you are head on with a ship doing 20kn and you are doing 10kn the effective closing speed becomes 30kn thats 10minutes of warning and as he's a ship you probably get more warning from him as he may be visible up to 20miles away so 40minutes warning.

There are some extra bits of detail in the vessel details of a Class A message. But I very much doubt they make any difference to you

 

[Daydream believer]

I suspect they did see you but their ARPA may well have plotted a course quite close to you mind you 60ft is seriously close.

I presume you have a Radar Reflector? if not that's where I would start.

Apart from that an AIS receiver is good option, and a transponder even better for limited visibility, you would normally fit a class B transponder.

What about putting the plotter to display AIS etc. on a board that slots into the washboard slots or a swing arm I used a RAM mount on my previous boats which worked well.

I have not one but 2 reflectors
I had not thought of a washboard mounting. Good idea need to sort the wiring so it can be easily disconnected as i do not want loads of wires etc hanging around when in port. Thanks for that not sure what you mean by R A M
Definitely going with the transponder but not sure if A or B:

 

[Daydream believer]

If you do go with AIS, I would recommend the Vesper Watchmate series for their very useable display software.

Pete

I have been in touch with them & had immediate helpful response. There's is class b & less than £1 K with aerial etc but if i really need class a i want to spend it now rather than blow £1k & find it is the wrong one

 

[ShinyShoe]

Try this link: http://www.shinemicro.com/AISOverview.asp#AB
Apart from the power difference which i don't think should worry you here's the other differences:
In a REALLY BUSY sea a Class B set will let Class A's talk instead. Even in the Solent Class B's seem to do plenty of talking. Maybe in Cowes week some Class B's will miss a beat if its really really busy. But I think you can fit something like 2000 boats into the 10miles radius before its a problem. If you are in water with 2000 boats I suggest you are on deck using your eyes to avoid boats!

Heading information may not always be sent. That said if you look at the majority of pleasure vessels on Marine Tracker they will be on Class B and are sending some heading information. Class B don't send a rate of turn. I'd guess you just turn!

Safety Text Messaging - depending on your Class B set you either send no message or only pre-configured ones eg a MOB button. You wont be sending things like 'Underway with engine', 'destination port' etc. But I'd put money on if you have a Class A you wont have the time when short handed to go updating things like that. (A good many commercial vessels don't seem to either!)

I'd want my AIS data on a chart plotter.

I'd want to be able to quickly set CPA alarm active or not.

RAM is a swivly thingy - http://www.ram-mount.co.uk/device-mounts-gps-marine-c-360_538.html

 

[davidwf]

I have not one but 2 reflectors
I had not thought of a washboard mounting. Good idea need to sort the wiring so it can be easily disconnected as i do not want loads of wires etc hanging around when in port. Thanks for that not sure what you mean by R A M
Definitely going with the transponder but not sure if A or B:

RAM mounts see http://www.ram-mount.co.uk/device-mounts-gps-marine-c-360_538.html quite expensive but given you are going to hang an expensive display on it I think they are worth it. I used a ball mounted one with the ball permanently mounted and just disconnected the plotter arm when locking up.

 

[dansaskip]

In rather similar dilemma myself - although no near misses yet. After a lot of thought and some research I have opted for a Vespa watch mate 850. As prv suggests

"If you do go with AIS, I would recommend the Vesper Watchmate series for their very useable display software. "

Not cheap but it seems to tick all the boxes, can have it just receive or receive and transmit to let those big things out there know you are there - haven't used it yet (boat ashore for winter) so no experience of its use Im afraid but self contained & standalone so doesn't rely on other kit ( I don't have or use a chart plotter), low power too . Best of luck in your search for a solution.

 

[johnalison]

In the end it all comes down to how much you are willing to spend. For £500 or so I would agree with those who advocate an active radar reflector. On the other hand, An AIS display is a very reassuring tool and before deciding on a transponder only I would suggest the OP has a look at AIS in action on another boat if he hasn't already, and he will see how helpful it can be.

 

[Mistroma]

I must admit that if OP is considering purchase of a class A transponder it sounds a bit excessive. An active radar reflector plus a cheap AIS receiver would probably be less than a class A transponder. Probably more frugal on power, able to see other vessels a long way off and large ships are more likely to spot him on radar than via AIS.

 

[prv]

Have to say I can't really see a good reason for a yacht to have Class A, but I'm not an expert on the technical details.

Pete

 

[Tintin]

Cover all bases...get a class b transponder and an active radar reflector.

The cost may seem high, but not if it saves your life.

 

[bbg]

Personally (as I've said before) I would go with a radar target enhancer (Sea-Me or Echomax) before an AIS transmitter. All ships will be using radar, not all will be effectively using AIS (the number with integrated ECDIS or a useful AIS display prominently mounted is presumably increasing, but it only takes one...). An AIS receiver is always helpful.

If you do go with AIS, I would recommend the Vesper Watchmate series for their very useable display software.

Pete

I would agree with that. Vesper provided me with excellent service and the kit works well. I can't think of any reason to fit Class A.

Radar target enhancer probably equal or higher on the priority list, but both is really the best solution for sailing solo.

 

[Daydream believer]

Cover all bases...get a class b transponder and an active radar reflector.

The cost may seem high, but not if it saves your life.

Sensible suggestion I will probably go down that route
I had thought that A & B were 2 different frequencies like radar but probably incorrect
What about active radar reflectors. Is that not a problem with those?

Do not know anyone with an AIS so cannot try out first. They will probable be wanting to look at mine!!!

 

[Koeketiene]

My question is :-
Should I be looking at class B or class A ?

Class A is for ships >300 GRT

 

[Rivers & creeks]

Just checking, you do know that 95% of all commercial ships do not have a plotter screen showing AIS targets? When you say that a transponder means that they 'know you're there' it means that your lat and long appear on a numerical display listing you and the three other closest targets. Sure, all new codings have to have a plotter type display for AIS so you've got to hope that the ship that's nearest has been built in the last five years or so. Otherwise you are relying on their RADAR which they will be using all the time that there is some one actually on the bridge and on watch. AIS receivers are superb, AIS yacht transponders are a triumph of marketing over reality.

 

[gjgm]

A receiver is very cheap, and at least you now know where the ships are, well before you can see them.Also, as you suggest, you dont risk being overconfident that THEY can see YOU.
Mind you there was an article a few years back suggesting that radar reflectors (not the active ones) were probably more dangerous than nothing as too many folk imagined ships could see you. The article argued it was better to have nothing, as then you paid alot more attention !