Sea-me or AIS transponder?

[bbg]

An old thread, I know, but it comes up first in a Google search, so here's my experience on the topic.
Offbeat has an old single band See-Me RTE, a Vesper AIS receiver and an Icom DSC radio. Sailing with this kit in the southern North Sea, the English Channel and now across Biscay and down to Lisbon, I've evolved this routine: use eyes and the AIS on 12 mile range setting (AIS, that is, I dont have bionic eyes) to identify vessels that pose a collision risk; when 3 to 5 miles away call them up on the VHF and tell them my intentions (usually turning to avoid them even if I should be the stand on vessel); ask them to confirm that they will maintain their course. On all occasions but one, the watch officer has replied quickly and professionally, confirming that they have me on radar and often quoting the cpa to me. Even that Yemeni coke fiend was right on the ball - very chatty in fact (irony - read the earlier posts in case anyone has a sense of humour failure).

I'm considering upgrading to the dual band See-Me as I plan ocean passages from next year. And I ought to work out how to get my AIS to send mmsi to my VHF; but this system has worked well for us in good vis, thick fog and at night.

If I had enough money I'd add radar in order to see small fishing vessels, land and squalls. btw, most (If not all) modest to large sized fishing vessels so far have had AIS fitted and switched on.

I have to say that I disagree with your approach of altering course when you are stand-on, and informing the ships of that fact.

If you are stand-on (which you will be when sailing, unless you are overtaking ), you should stand on. When offshore and CPA is more than half a mile, there is nothing to do. Just monitor.

My practice, when I was at all concerned (which was maybe twice during a season of offshore sailing and a transatlantic crossing) was to call them on the radio, identify myself and ask if they had seen me. If I was really concerned (only once), I asked what their intentions were.

If they hadn't answered I would, at some point, have to make a decision about whether to take avoiding action, but generally, if you are stand on then you have an obligation to maintain your course.

 

[LadyInBed]

Big ships mainly use Radar, small boats mainly use AIS receiver.
If you have an AIS transceiver you will see big ships and small stuff will see you.
You already have a Radar reflector, if you fit RTE then your visibility will only increase to anyone using Radar and it won't help the radar-less boats like you!

 

[GHA]

Ocean I'd guess a good radar return would be better than an AIS transponder, obviously both is best And not that pricey to send AIS..

On a steel boat with a good echo mostly and ships that you do actually come across once in a while do any dogleg type maneuvers to give you more sea room before they appear over the horizon - usually finished more than 5 miles away so guessing they would be happier the further away they pick you up.

Best to think both though...

 

[PhilipH]

Recently on passage from Santa Maria, Azores to Porto Santo, Madeira Is. On approaching North end of Porto Santo at night Chinese cargo ship popped up on the AIS with a CPA of 1/4nm. We under sail. At 4nm called him up on VHF and all very polite and he altered course so passed about 1nm distant. Visibility was great so we did not have the Sea-me turned on. We do a radar sweep about every 30 mins but depends where we are and how busy likely to be. In fog or in busy fishing waters Sea-me is on and radar sweep more frequent if not permanently on. If cost is an issue then it depends where you are sailing and likely conditions as to which to choose if you cannot afford both. Incidentally when there is lightning around the Sea-me is definitely turned off.

 

[john_q]

I have an old Single band See-Me which I have to turn off if I want to use my Radar as the See-Me will detect it and the alarm goes off continuously I found at sea, when we get a recognisable noise pattern from the See-Me we will find the target on the RADAR at about 14 miles (this is how I got to talk to Alex Thompson)We also came across a ship in Mid Atlantic who we spoke to via VHF who did not have their Radar switched on!!!

 

[differentroads]

I have to say that I disagree with your approach of altering course when you are stand-on, and informing the ships of that fact.

If you are stand-on (which you will be when sailing, unless you are overtaking ), you should stand on. When offshore and CPA is more than half a mile, there is nothing to do. Just monitor.

All right and proper when we need to do the correct and predictable thing to avoid a collision from occuring. I have low tolerance for proximity to ships though - a cpa of a mile is the boundary of my comfort zone. So I usually take action to pre-empt situations that I imagine the colregs were written for.

I'm overcautious, I admit, but the combination of RTE, AIS receiver, VHF and the professionalism of merchant navy watch officers has served me well. I'd have an AIS transceiver too if I had more confidence that ships were not habitually filtering Class B transmissions out. As it is, I wanted a standalone AIS set with a display and could only afford a receiver as an EPIRB and other stuff for the grab bag were much higher up the priority list.

Now, as I'm about to head out of Lisbon to round Cape St Vincent and then through the Straits of Gibraltar, I will have jinxed myself by asserting my approach and collide with a cargo ship that I'm overtaking while surfing down a swell that's come from one of those storms that are battering Britain at the moment. Watch out for one of the unlikliest MAIB reports ever! ?

 

[bbg]

Well, I guess we're different.
I recall a crossing near Land's End where I was content with a CPA of 0.1 mile in front of me, after I had called the ship and confirmed that he had seen us. Didn't ask him to do anything or his intentions. Just told him that my AIS showed he would cross in front of me, and was he comfortable? "Yes", so I just kept an eye on him as he passed in front. It was not a 90 degree angle, so I was not closing on his track very quickly. No worries.

Only other time I can remember calling a ship to discuss a "crossing* was with a CPA of less than a mile, at dusk. But I hadn't spoken with anyone for a few days and I really just wanted someone to talk to, even if it was only for a minute or so.

 

[LadyInBed]

When I went down to Portugal last year I didn't see any ships, maybe I was asleep

 

[Seven Spades]

Out of interest has anyone here fired off a white flare?

 

[Zing]

A lot of ships don’t see your AIS signal. Some ships even turn off Class B to avoid clutter. Get an active radar transmitter to be sure you are seen.

Don’t use the VHF. The MCA recommend it is not used as a collision avoidance tool. Stick to colregs.

 

[westhinder]

On passage from the Azores to Nova Scotia, a pretty empty stretch of ocean, we had AIS and Sea Me dual band. We only encountered a couple of ships, whose presence was always first announced by the beep of the Sea Me, indicating that we had been painted by a radar beam. In most cases at that point there was not yet an AIS contact, which may be down to the fact that the Sea Me antenna was on the second spreader and the AIS aerial on the transom arch. Still we spotted ships on AIS over 30 miles away. My estimate is that the Sea Me was hit by radar from as far as 50 miles off. Pretty impressive.

 

[jamie N]

My EchoMax will ping a supply ship at about 10 miles, about the same distance as my AIS receiver. Crossing to Fair Isle in thick fog, a couple of months ago, it gave great comfort to know that the other vessel's radar are seeing me as a 100m long steel thing, and not a 7m long wooden thing. Having it made easy for them to avoid me by just watching the CPA from my XPNDR on their AIS was nice, as was being able to monitor their changing bearing to me, or not. If not, then I've time to react an make us both safe. This was the 1st time that I've 'felt' the true benefit of the £900's worth of kit, probably the best 'real world' options available to me, on my £2k's worth of boat, and can now say, that I'd have happily paid more! I do laugh when I see a large, posh AWB, with all of the luxuries built into it, and tuppence worth of radar reflector, when the 'crew' have spent more on Dubarry's than I've spent in total!

 

[bobgarrett]

The CG dont understand the difference between the theory and the practice, then. I took avoiding action whilst sailing across the channel, on the starboard bow of a ship. Afterwards, I tried two calls using MMSI from the number picked up on AIS, both cancelled, and twice on Channel 16, both ignored.

As Graham of these forums explained to me, you have to assume the watch officer is a Liberian coke addict who is having a kip.

We had the same experience this year with a ship not responding to calls on Ch 16 nor DSC calls. We then took avoiding action which resulted in a brief conversation with one ship at my initiation as we would then be going closer to him, then another ship called us to confirm our intentions after passing astern of the second ship.
This shows how everyone assumes that rules are followed and one doesn't follow the rules then many have to take action.
We reported the first ship via CHIRP. We will see if anything comes back but I doubt it will though I hope the owners did pass the question to the skipper.
Radar would not have allowed identification of the ships or they of me; AIS did.

 

[Yealm]

All right and proper when we need to do the correct and predictable thing to avoid a collision from occuring. I have low tolerance for proximity to ships though - a cpa of a mile is the boundary of my comfort zone. So I usually take action to pre-empt situations that I imagine the colregs were written for.

I'm overcautious, I admit, but the combination of RTE, AIS receiver, VHF and the professionalism of merchant navy watch officers has served me well. I'd have an AIS transceiver too if I had more confidence that ships were not habitually filtering Class B transmissions out. As it is, I wanted a standalone AIS set with a display and could only afford a receiver as an EPIRB and other stuff for the grab bag were much higher up the priority list.

Now, as I'm about to head out of Lisbon to round Cape St Vincent and then through the Straits of Gibraltar, I will have jinxed myself by asserting my approach and collide with a cargo ship that I'm overtaking while surfing down a swell that's come from one of those storms that are battering Britain at the moment. Watch out for one of the unlikliest MAIB reports ever! ?

Is it legal for big boats to filter Class B ?
Does it need international law change to improve safety at sea for all ?

 

[bobgarrett]

One other important point re AIS. If you are a boat is a sailing vessel be sure to set the vessel type when installing it as Sailing Vessel not the default Pleasure Vessel. Too many installers, even the professionals, make this mistake. Then ships may not make the right decision. We have seen this and even heard a VHF discussion between a ship and a yacht about it.

 

[jamie N]

Very good point!

 

[RichardS]

Is it legal for big boats to filter Class B ?
Does it need international law change to improve safety at sea for all ?

Don't worry .... it only happens on the Forums.

(Actually, it once did happen in the real world but that was in The Solent, so not that real. )

Richard

 

[LadyInBed]

A lot of ships don’t see your AIS signal. Some ships even turn off Class B to avoid clutter. Get an active radar transmitter to be sure you are seen.

Don’t use the VHF. The MCA recommend it is not used as a collision avoidance tool. Stick to colregs.

What is your evidence of this?
I can understand that it might be true in places like the Solent to reduce clutter but not when ships are ploughing​ up and down the Channel.
As for VHF, when going X Channel, I have asked ships their intentions several times when AIS has told me that they will pass very close and AIS hasn't seen them change course. The response is always​ positive and the odd occasion when they don't reply, AIS sees them change course.

 

[Zing]

What is your evidence of this?
I can understand that it might be true in places like the Solent to reduce clutter but not when ships are ploughing​ up and down the Channel.
As for VHF, when going X Channel, I have asked ships their intentions several times when AIS has told me that they will pass very close and AIS hasn't seen them change course. The response is always​ positive and the odd occasion when they don't reply, AIS sees them change course.

There is an MCA advice note on VHF:
https://www.gov.uk/government/publi...vigation-watchkeeping-safety-use-of-vhf-radio

On AIS, not all ships have AIS, so of course, those that don't can't see you and often those that do can't see you anyway. Information concerning the inability of ships to pick up AIS is in here (and on weak radar returns):
https://www.atsb.gov.au/media/1539485/mo-2009-008.pdf
This is a really good report by the way and worth reading thoroughly.

It is often reported that ships turn off class B. It clearly will happen mainly when there is a lot of clutter and when in a channel for example, so big ships only need to deal with other big ships.

 

[GHA]

It is often reported that ships turn off class B. It clearly will happen mainly when there is a lot of clutter and when in a channel for example, so big ships only need to deal with other big ships.

It's not a problem, if there's that much traffic like in the Solent the AIS is of little use, look out the window.
It's feasible that a ship might forget to unfilter but if anything happened and that was the case they would get hammered by the authorities for running a very bad ship, day to day for us class B filtering is a non issue. Been done countless times already.
https://www.panbo.com/class-b-ais-filtering-the-word-from-dr-norris/