AIS receive only or transponder?

[Richard Solomon]

I'm adding AIS and a new chart plotter to my 40' sailboat. I'd like an AIS display unit at the chart table, outputting to the new chart plotter in the cockpit. Cruising grounds, for now, are California and Mexico; lots of shipping lanes, etc. What's the collective wisdom on spending the extra money to get a transponder unit such as the Vesper WatchMate 850? Will it add a sufficient amount of safety to justify the higher (around $600 U.S.) cost?
Thanks for your input, and fair winds!
Richard
Santa Barbara, CA

 

[KAL]

Hi and welcome to the forum!

Not sure how busy your shipping lanes are and whether or not your area suffers from sea fog or other bad visibility, but if you can, I would go for the transponder. Used mine for the first time last year crossing the English Channel and it was amazing to see the huge ships altering course ever so slightly so as to accommodate my anticipated track. Meanwhile, I was doing the same for them so there were never any anxious moments.

Doesn't mean you stop keeping a decent watch, but at least everyone has information well in advance and can take appropriate avoiding action.

 

[chubby]

I had a receiver for a season but have upgraded to a transponder: I liked the idea of being able to positively ID shipping but even more for them to see me and to be able to get my course and speed etc, an alternative might be a radar enhancer but the thought of a transponder was attractive, a by product is that my family ashore with the marine watch website can see where I am!

 

[VicMallows]

The downside is that in places like the Solent AIS is becoming so cluttered with Class B (yacht) transmissions that it will soon be useless. A pity since it is (was) a very useful tool for keeping out of the way of the monsters ... and even the ferries.

So soon, we the yachties, will be filtering out the Class B ..... and you can guess what the professionals will be doing. (I wonder if NASA will sell you the 'old' chip ... before they added the Class B capability )

Vic

 

[davidej]

Could we perhaps persuade pleasure boat owners to transmit only when they are actually crossing shipping lanes or in a similar high-risk situation.

Probably not!

 

[doug748]

Could we perhaps persuade pleasure boat owners to transmit only when they are actually crossing shipping lanes or in a similar high-risk situation.

Probably not!

No probably not.

Quite a number seem to transmit in the marina.

 

[timbartlett]

The downside is that in places like the Solent AIS is becoming so cluttered with Class B (yacht) transmissions that it will soon be useless. A pity since it is (was) a very useful tool for keeping out of the way of the monsters ... and even the ferries.

So soon, we the yachties, will be filtering out the Class B ..... and you can guess what the professionals will be doing. (I wonder if NASA will sell you the 'old' chip ... before they added the Class B capability )

Vic

Or could we persuade people to drop this carp about "filtering out AIS B"?
Yes, filtering happens. IMO make filtering functions compulsory for new installations on solas vesels. But it does not mean that all AIS B targets are deleted. It means that non-hazardous targets are deleted -- so the hazardous ones stand out even more.

Of course the wit of man is such that some bright spark of a watchkeeper might manage to find some particular control setting thatwould delete all class Bs -- just as he might not look out of the bridge window. But it would be a lot more difficult to do accidentally than not looking in the right direction or winding the STC up too high on his radar -- and it would be a seriously career-damaging move.

And bear in mind that the main reason yot AIS looks so "crowded" is because most yots are trying to display everything, all at once, on a screen the size of a fag packet.

 

[VicMallows]

Or could we persuade people to drop this carp about "filtering out AIS B"?

If I understand you correctly, I think you are referring to the suggestions being bandied around that commercial ships are deliberately 'filtering out' ALL class B transmissions. I don't think that for one moment. They also probably have the software (and ability to use it) to selectively see only relevant targets as you describe.

My concern is from the perspective of the typical yacht owner looking at his screen, which I agree is often pathetically small. As far as I am aware very few yet have the selective filtering you suggest, including most PC based chartplotter solutions.

Vic

 

[pvb]

I really think that any owner of a small boat who buys an AIS transponder hoping it will increase his safety is impossibly optimistic. If you want to increase safety, maybe get an active radar reflector. If you want electronic toys, get an AIS transponder.

 

[Cardo]

I really think that any owner of a small boat who buys an AIS transponder hoping it will increase his safety is impossibly optimistic. If you want to increase safety, maybe get an active radar reflector. If you want electronic toys, get an AIS transponder.

Surely anything that helps you be seen will add another link to the safety chain? Whilst I wouldn't fully rely on an AIS transponder to get by, I would certainly feel a little more comfortable with it.

 

[pieter2]

I found my AIS transponder very helpfull, sailing very thick fog while crossing traffic lanes.
The interesting part is that you are able to see the characteristics of the other boats (name, speed, direction, etc). So it is very easy to call eachother on VHF and confirm course / change of course.
This works both ways (with a transponder).
I heard about filtering out the B-class boats as well. I suspect this is being done in to busy areas with good visablity, but when it counts (fog) everyone is using every means to 'see' eachother.
You should never rely on anything for 100%, but it sure helps.

 

[Twister_Ken]

I was looking this morning at an article I wrote for a logistics company a few years back. I was rather pleased with it. It covered how to package delicate goods so they stand a good chance of arriving undamaged. The final sentence was "Don't rely on "Fragile" and "Handle With Care" labels as a substitute for careful packaging. They are only for information purposes. They confer no magic powers."

I feel the same could be applied to AIS. Nice to have, but it won't save your butt. No magic powers. Rely on established look-out and collision avoidance techniques.

 

[Tradewinds]

Transponder

Remember how we all discussed the AIS track of the Costa Conrcordia on the way to her final resting place?

Now imagine it's you as the hapless skipper of 'Saucy Sue' as you wend your way through the shipping lanes (see shipping lanes thread) transmitting your errors of judgement to all & sundry - leaving a trail for the authorities to pour over at their leisure in the weeks before your court appearance.

I think I'll stay incognito.

 

[samwise]

The AIS receiver is a boon. We used ours in anger for the first time two seasons ago and I would not be without it. This, together with radar overlay on the GPS screen ( cereal box size rather than fag packet) has greatly reduced the anxiety factor in TSS crossing and poor visibility situations.
We felt that the transmitter was overkill (a)Because I did not wish to add to the increasing clutter of transmissions that must eventually reduce the effectiveness of the system and (b) because I feel it could lead to complacency and lax traditional watchkeeping in the belief that the big ships will take the action to avoid you, rather than the other way round.

I apply the same philosophy on the road -- especially on my motorcycle -- on the basis that it is my responsibility to keep clear and maintain my "safety bubble" and never assume that the other drivers have seen this big guy on a big yellow motorbike coming towards them. Advances in marine electronics have dramatically increased safety at sea but I feel we should resist the siren call from the industry to load ourselves up with all this expensive stuff and concentrate on the kit that provides real safety benefits.

 

[ribrage]

Or could we persuade people to drop this carp about "filtering out AIS B"?
Yes, filtering happens. IMO make filtering functions compulsory for new installations on solas vesels. But it does not mean that all AIS B targets are deleted. It means that non-hazardous targets are deleted -- so the hazardous ones stand out even more.

Of course the wit of man is such that some bright spark of a watchkeeper might manage to find some particular control setting thatwould delete all class Bs -- just as he might not look out of the bridge window. But it would be a lot more difficult to do accidentally than not looking in the right direction or winding the STC up too high on his radar -- and it would be a seriously career-damaging move.

And bear in mind that the main reason yot AIS looks so "crowded" is because most yots are trying to display everything, all at once, on a screen the size of a fag packet.

You raise a good point here, on the bridge of the research vessel here we have four 28 inch displays that are used for radar, plotter and AIS info or combinations of all info , we also have a small "vesper" sized unit that is used as a stand alone AIS next to one of the vhf radios.

I can assure you that we dont filter out b class signals nor are any of our screens cluttered to the point we cant read the information and the small unit feeds info directly to a vhf so that we could easily call any mmsi number to discuss crossing situations.

Radar enhancers such as the sea me do work but it doesnt feed any other information to the bridge watch such as vessel name, mmsi, course, speed , cpa etc, so all we can do is call "vessel in position blah blah blah this is survey ship blah towing 6k of arrays please alter course cos we cant !

IMHO an AIS system is well worth the dosh

 

[prv]

on the bridge of the research vessel here we have four 28 inch displays that are used for radar, plotter and AIS info or combinations of all info

That's good to hear. By contrast, the only ship bridge I ever go on (Stavros) has what I believe is the minimum required fit - a small blue box with a few lines of text on it, mounted in a corner near the nav light controls. Radar and a pair of visual lookouts are the means of detecting other vessels.

There's obviously a scale of AIS provision on ships - from the text display in the corner, via perhaps a leisure display added as an extra, to an early AIS-equipped ECDIS, to the full Starship Enterprise fit on your research vessel. It would be interesting to know the distribution along that line of the world's active shipping.

Pete

 

[Colvic Watson]

Tim Bartlett will never be accused of having an open mind on this, or on almost any subject. I'd love a 28" screen but sadly that would mean I couldn't see out of the wheelhouse window. Also, I can't afford it, so I use the best I can which is a 7" screen, now that gets cluttered by AIS class B signals unless I zoom in so close that I can't see the class A signals from 3 miles away, and the class B signals trigger endless CPA alarms so I turn off the CPA alarm altogether. Tim can't understand how this works on a small yacht so his comments on AIS are like a stuck record "buy a huge screen then everything will be lovely". Shame, he clearly understands engines so perhaps he should confine his comments to what he knows.

 

[ribrage]

That's good to hear. By contrast, the only ship bridge I ever go on (Stavros) has what I believe is the minimum required fit - a small blue box with a few lines of text on it, mounted in a corner near the nav light controls. Radar and a pair of visual lookouts are the means of detecting other vessels.

There's obviously a scale of AIS provision on ships - from the text display in the corner, via perhaps a leisure display added as an extra, to an early AIS-equipped ECDIS, to the full Starship Enterprise fit on your research vessel. It would be interesting to know the distribution along that line of the world's active shipping.

Pete

Hi Pete

of course you are right in that levels of equipment vary and ours is probably not the norm - towing ten million quids worth of silly string does tend to focus attention on collision avoidance , sounds like our FRC has more electronics than the good ship Stavros :+)

I think as ships are replaced and the old stuff run up a beach in India the level of equipment on new ships will improve, the vessels plying the major trade routes tend to be newer and in good shape.

Although it has to be said I have had to launch the RIB before, not to rescue an M.O.B but to stop a shiney looking container ship running into our gear, we ask for a five mile clearance astern of our cables as a safety margin and as the noise from their props disrupts the data stream........ sadly some ships arent always as obliging.

At least by reading the AIS data we know who to send the insurance claim too !

 

[ribrage]

Tim Bartlett will never be accused of having an open mind on this, or on almost any subject. I'd love a 28" screen but sadly that would mean I couldn't see out of the wheelhouse window. Also, I can't afford it, so I use the best I can which is a 7" screen, now that gets cluttered by AIS class B signals unless I zoom in so close that I can't see the class A signals from 3 miles away, and the class B signals trigger endless CPA alarms so I turn off the CPA alarm altogether. Tim can't understand how this works on a small yacht so his comments on AIS are like a stuck record "buy a huge screen then everything will be lovely". Shame, he clearly understands engines so perhaps he should confine his comments to what he knows.

I was nt suggesting that leisure vessels should have a 28 inch screen purely that from a commercial point of view some of us are monitoring large screens and in high density leisure boat scenarios we dont filter out the class B targets.

 

[timbartlett]

Tim Bartlett will never be accused of having an open mind on this, or on almost any subject. I'd love a 28" screen but sadly that would mean I couldn't see out of the wheelhouse window. Also, I can't afford it, so I use the best I can which is a 7" screen, now that gets cluttered by AIS class B signals unless I zoom in so close that I can't see the class A signals from 3 miles away, and the class B signals trigger endless CPA alarms so I turn off the CPA alarm altogether. Tim can't understand how this works on a small yacht so his comments on AIS are like a stuck record "buy a huge screen then everything will be lovely". Shame, he clearly understands engines so perhaps he should confine his comments to what he knows.

I'm afraid you are misrepresenting my opinion -- whether by accident or intent I cannot tell.
One of the common arguments against yachts installing AIS B is that it will clutter the displays of ships. This appears to be based on yotties perceptions of clutter, based on very small screens, so it does not apply to ships, where screens are (by law) considerably bigger.

Of course I appreciate that most people cannot fit a 28-inch display. I am sorry if I did not make that clear, but I regard it as self-evident. There are plenty of solutions: my personal favourite would be not to overload a small display with excessive information -- i.e. have either separate displays for each type of data, or one display switched between different types of data.

You are welcome to your opinion, and to express it. OTOH, you might like to consider the possibility that the reason my mind appears (to you) to be closed is because my opinion is based on considerably more knowledge of the subject than you appear to have.