AIS SART

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lpdsn

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I've been looking at AIS SARTs. Seems they've been out for a few years now and seem pretty useful but it's almost as if they've been hushed up, so I'm keen to hear if anyone else is using them.

Any feedback on experiences? Anyone had to use one for real? Anyone picked up an emergency signal from one?

One of my doubts is that a lot of AIS installations may not pick the signal up correctly as they use message type 14 for part of the alert. As far as I can tell my receiver will, but as I convert the messages to N2K using an Actisense NGW-1-AIS that doesn't support VDM sentence 14 I may never know if someone in the vicinty has set one off. (I am considering another display that will interface directly using NMEA0183.)
 
They're intended to indicate your position to your own boat, so your crew can get back to pick you up. If you invest in them, you'd naturally make sure that your on-board kit does something sensible.

They're not intended to signal distress to third parties, the range is too short under most circumstances and, as you observe, not everyone is equipped to notice. For that you need a 406MHz PLB.

Pete
 
prv said:
They're intended to indicate your position to your own boat, so your crew can get back to pick you up. If you invest in them, you'd naturally make sure that your on-board kit does something sensible.

They're not intended to signal distress to third parties, the range is too short under most circumstances and, as you observe, not everyone is equipped to notice. For that you need a 406MHz PLB.

Pete
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I've not found anything yet that says they're restricted to just your own boat. Seems they transmit at 1W and a range of up to 5NM is expected. Obviously, I understand that it may be less under non-ideal circumstances. I'm often crossing shipping lanes (albeit not as busy as the English Channel) and ferry routes so there's quite often commercial shipping within 5NM. Just wondered if anyone had any real life experience of them.

I have a PLB already.
 
lpdsn said:
I've not found anything yet that says they're restricted to just your own boat.
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There isn't some kind of legal restriction, they're just not very well suited for other purposes.

They were originally invented for events like the Clipper Round the World Race, to enable the yacht to return to a man overboard in the Southern Ocean. At the speeds they go, with big swells, doing it visually is more or less impossible, and there's no point signalling for external help because it's all many days away.

Pete
 
They are not restricted to your own boat in any physical way, it's just that in many cases it may be that only your own boat is in range. I suspect that's what Pete meant.

I reckon 5NM is hugely optimistic. That's about all you get with a decent handheld VHF on an average day. 1w at sea level isn't going to be anywhere near, IMO.

If you are on your own, then unless you are in a busy area it's not going to be much help, your PLB is a better option. If you have crew it might help them to get back to you easier, you'd really have to provide all of the crew with one each though, unless you don't like some of them :)

I think the PLB is probably a must have for single handing. If you wanted to add an AIS SART it can't hurt, even if it doesn't help.
 
prv said:
There isn't some kind of legal restriction, they're just not very well suited for other purposes.

They were originally invented for events like the Clipper Round the World Race, to enable the yacht to return to a man overboard in the Southern Ocean. At the speeds they go, with big swells, doing it visually is more or less impossible, and there's no point signalling for external help because it's all many days away.

Pete
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Not saying they wouldn't be very useful under those circumstances with your own vessel likely to be the only one within a few miles, but I've not found that restriction stated in anything I've found on-line yet.

In the North Channel/Irish Sea external help shouldn't be many days away. They just seem useful in that they bypass the satellite & MRCC path and broadcast to nearby vessels. I guess as no one else is posting on this the impression I get that there is minimal market penetration isn't being challenged.
 
lpdsn said:
I've not found that restriction stated in anything I've found on-line yet.
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What "restriction" are you talking about?

I described the purpose they were designed for (as stated by one of the designers, I'm trying to find the video of it) and for which they are well suited. For other uses they are not very well suited, but nobody except you has said that such uses are "restricted".

Are you "restricted" from using an adjustable spanner as a hammer?

Pete
 
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Nearby vessels? I've cruised the North Sea a lot and near the coast you pass quite a few boats at less than a mile but otherwise there are very few you actually get within a mile of, and even that is chancing it with 1w at sea level. Still it's great for your own boat and when the mother ship calls for SAR they can use their helicopter/lifeboat AIS to home in on you. But don't imagine for a moment that a personal AIS beacon is going to trigger much if anything beyond your own boat.
 
lpdsn said:
In the North Channel/Irish Sea external help shouldn't be many days away.
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I get the feeling from the above that lpdsn is talking about this:

5_s5.jpg


http://www.mcmurdomarine.com/images/s5/5_s5.jpg

And Pete is talking about this:

5_s10.jpg


http://www.mcmurdomarine.com/images/s10/5_s10.jpg

Very different devices, one being on a pole and intended for disabled craft or liferafts; the other being for a MOB in the water. Thus a conversation slightly at cross purposes.

The top one is a SART. the other one is a personal beacon.

Apologies if I've got it wrong gents.
 
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lpdsn said:
Thanks. Definitely SART from my point of view.
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So you were talking about the one in the top pic ?

I think that's even less useful than the PLB style one. If you've had to deploy the raft the only people who could possibly receive the transmission would be on other boats.
 
https://www.google.co.uk/search?q=a...ibbNAhWLKcAKHVO7AbIQ_AUICCgB&biw=1137&bih=601

I think it's a waste of money. If you've deployed the liferaft the chances are that most of the people who would receive the transmission would be within visible range anyway.

A handheld VHF with GPS/DSC makes much more sense to me. A much higher percentage of vessels will have DSC than will have AIS. A DCS mayday will alert all of those vessels and a voice mayday will alert the others. A handheld will transmit at 5 or 6 watts and will have a much greater range than a 1 watt AIS SART.
 
I think two things need to be seperated in any rescue strategy: calling for help and then helping the rescuing vessel pinpoint you.

How you call for help is going to depend on the nature of the emergency. In the case of a MOB (from a crewed yacht in daylight hours) you would hope that your absence is fairly quickly noted and so the situation immediately moves to stage 2, pinpointing the MOB who hopefully won't be far away. The MOB would be expecting the yacht itself to be callng for additional help. This is the basic set of circumstances in which the personal beacon AIS is intended to operate.

In the case of abandoning to a liferaft, you are going to need to call for external help- probably a SAR asset. Neither the AIS SART or a personal AIS beacon have the range to do this effectively, nor does an AIS alert necessarily express the immediacy of the emergency to any receiving vessels. Calling for help is best done via a VHF with a GPS position, but if youy don't hava a VHF or get no response- depends on the nature of the emergency- your best bet is going to be a PLB or EPIRB. Incidents like Rambler 100 (http://www.mcib.ie/reports.7.html?r=159) and a MOB from a RIB in Pembrokeshire (http://www.bbc.co.uk/news/uk-wales-south-west-wales-23469810) indicate the likely time between firing a PLB and rescuers being at hand is going to be in the order of 2-3 hours in coastal waters. Incidentally, the point of lowest morale in a liferaft is thought to be around 2.5 hours after abandoning, when the reality of the situation is starting to sink in for the occupants. By this point, however, someone will be in the area and looking for you so this is the time to help them locate you, and this is where a SART (either AIS or radar) comes in. Because the SAR vessel is actively looking for any indication of where you are, you can be pretty sure they will notice an AIS alert straight away, so the SART should be effective.

Personally I can't think of a reason why the personal beacon wouldn't function just as well as the AIS SART in those circumstances. In an ideal world I'd have an AIS beacon on every LJ (we already have PLBs on each) and a radar SART in the grab bag. But the point is that all the AIS systems are for guiding rescue to you, not calling for help- a strategy which relies on them to do both might work (by luck) but it quite probably wil not- i.e. it is not robust enough.
 
PaulRainbow said:
https://www.google.co.uk/search?q=a...ibbNAhWLKcAKHVO7AbIQ_AUICCgB&biw=1137&bih=601

A handheld VHF with GPS/DSC makes much more sense to me. A much higher percentage of vessels will have DSC than will have AIS. A DCS mayday will alert all of those vessels and a voice mayday will alert the others. A handheld will transmit at 5 or 6 watts and will have a much greater range than a 1 watt AIS SART.
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I think it's about having 'layers' of rescue equipment so that you have redundancy, becasue what you will have available to you depends on the emergency.

Calling for help:
a) Fixed masthead DSC & voice VHF
b) portable DSC & voice VHF
c)EPIRB/PLB

Helping rescuers locate you:
a)Radar SART
b)Flares
c)Personal AIS beacon

Everything plays its part depending on circumstances.
 
Just a note, most PLB and EPIRB transmit on both 406 MHz to the satellites and also transmit a homing signal on 121.5 MHz, the aim being that the satellite signal will get the SAR assets to your general location whilst the 121.5 mhz signal lets the lifeboat or helicopter home in on your exact location. No need for additonal bits of gear just to provide the homing signal.
 
duncan99210 said:
Just a note, most PLB and EPIRB transmit on both 406 MHz to the satellites and also transmit a homing signal on 121.5 MHz, the aim being that the satellite signal will get the SAR assets to your general location whilst the 121.5 mhz signal lets the lifeboat or helicopter home in on your exact location. No need for additonal bits of gear just to provide the homing signal.
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That is true, and some SAR beacons- such as those in the offshore oil industry- are 121.5 only, becuase these can legally be automatically triggered on entering water, which a combined 406 beacon can't. I believe the 121.5 component of the beacon only transmits with around 0.25 watts though and are intended mainly for air assets to locate the person(s) in distress. Although my understanding is that RNLI lifeboats carry the equipment needed to make use of the 121.5 signal and there is no reason why they would not be useful in a coastal rescue situation, I have never read a report of the 121.5 signal being used in one. Consider this passage from the MCIB Rambler 100 report:

At 19:30 hrs, after making several unsuccessful attempts to contact ‘Rambler
100’ by VHF on Channel 16 and satellite phone, MRSC Valentia declared
‘MAYDAY’ and tasked Coast Guard Helicopter R115 from Shannon. The
Baltimore lifeboat was also en route to a new position (51°21.10’ N,
09°39.15’W) supplied by MRSC Valentia. They also made repeated calls to
‘Rambler 100’ on Channel 16, but received no response. Visibility was down
to approximately 0.5 nm in fog.

At 19:46 hrs, one of the lifeboat crew saw a light flashing through the fog. As
they approached the light, they could see an upturned yacht. MRSC Valentia
was immediately informed. At 20:00 hrs, the Baltimore lifeboat arrived at the
yacht at position 51°20.50’N, 09°37.80’W to find 16 people on top of the
upturned hull.
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Note that despite the poor visibility, there is no mention of the lifeboat trying to find Rambler via 121.5Mhz equipment- instead the casualty was located by visual means. The report does notexplicitly say whether the PLB fired by Rambler was a combined beacon or a 406Mhz alone; but if the Lifeboat had tried to find the casualty by looking for a 121.5Mhz signal, their failure to do so would be an event of interest to the MCIB narrative, either taking the form of a recommendation to use combined beacons (should 121.5 not have been present) or in the form of a note on the dificulty of using the signal (if it was being transmitted by Rambler's PLB).

Even the RNLI have to prioritise one thing or another and my feeling is that 121.5Mhz is not going to be the number 1 means by which they try to home in on you when the reach the position supplied by the MRCC as derived from your PLB's GPS reporting. In this rescue the casualties were sending a visual signal.

Here is part of the MAIB safety digest narative for the other incident I linked to above, which is about a MOB from a RIB in Pembrokeshire:

When the RIB was about 5 miles offshore,
rough seas were encountered, so the helmsman
reduced speed from around 24 knots to
between 14 and 17 knots. All was well until
the RIB landed so violently and with such force
after riding over one of the moderate waves
that the helmsman’s seat was wrenched from
the deck. As a result, he was thrown overboard.

...

The PLB alerted the local MRCC, which
contacted the wife of the RIB owner, who
confirmed that he was at sea in the area of the
distress beacon. In a bizarre twist of fate,
however, the coastguard then received a report
that the RIB had since arrived at its destination.
In fact, this was a different boat with the same
name. After some delay, the situation was
resolved and a full scale SAR operation was
initiated. Ferries, fishing vessels and local
leisure craft converged on the PLB’s position.
RNLI lifeboats and a rescue helicopter were
also tasked.

A passenger ferry spotted the empty RIB and
the helicopter located the helmsman 300m
from his boat. After 1 1/2 hours in the water,
the RIB owner was winched on board the
helicopter.
Click to expand...

In this incident the RIB itself was spotted by a ferry acting on an MRCC mayday- essentially providing a large orange visual indicator as to the position of the MOB to a non-SAR vessel engaging in the rescue effort. Had this been a liferaft and not an MOB, the ferry might not have been able to spot it visually- but it might have noticed an AIS SART or a a series of flares, because it was looking for a casualty. I think it very probable it would have been immediately alerted by a radar SART. What it certainly wouldn't have done is notice a 121.5Mhz signal, because it would not have been equipped for that.

PLBs have a very good record now in alerting SAR to dire emergencies, even in catastrophic emergencies far from land- consider Cheeky Rafiki- so much so that, if VHF/DSC/GPS is not available or does not work or is not available, the PLB is a completely effective means of calling for help. Attracting help once a SAR effort is launched however remains more complicated and IMHO requires more redundancy than the aero homing signal. Visual signals- laser or pyro flares- are essentials for a grab bag, and there is something to be said for personal daylight or miniflares (RNLI crew all carry a daylight flare in their lifejackets). This is probalby enough for the kind of coastal day sailing most of us do, but further offshore a grab bag SART, radar or perhaps AIS, is a very good idea, and I don't think the 121.5 signal of the PLB is really equivalent.
 
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