Split from a topic in another section:
For lack of a better "main German connection", here's my input on the easy Rescue:
I held an engineering sample of this product in my hands late January on the "boot Düsseldorf" fair at the Weatherdock booth. A product like this is urgently missing, at least in Germany where AIS is more widespread and has been for many years, and I commend them for doing it as it allows to locate your own MOB with kit that is already installed on your boat.
The alternative is a 121.5 MHz homing mechanism, either handheld (e.g., ACR Vecta) or fixed install (e.g., Crewfinder RT-202), which is many times as expensive (not possible within my budget), requires a trained operator in the case of the handheld and does not allow other boats in the area to participate in the rescue.
However, in my opinion, it has some serious drawbacks:
- Antenna: When stowed, the antenna is folded most of the way around the edge of the unit. The antenna is aluminum and shaped like window blinds (curved along the width not the length) which gives it a tendency to open but not very strong. The sample I held had gone through a thousand hands and so the antenna had lost most of it's tendency to open while the real one only ever needs to open once. I am still dubious, though, about it folding open and staying open while attached to a lifejacket in any serious wind and sea. A unit like the ACR Mini B 300 ILS will give you a whip mark across the face if you are not careful when releasing the antenna.
- Position above the water: I was told that one of the German makers of lifejackets (Kadematic) would adapt a vest to take this unit and hold it high above the water. I didn't look at the vest. Another German lifejacket maker (Secumar) has a model to hold up a 121.5 MHz transmitter beacon which looks impressive so I think that it can be done. The point is that with this type device it *must* be done. Unlike with a typical PLB (121.5 MHz and EPIRB), if the antenna is horizontal at water level, it will be next to useless.
- AIS only: The unit does not additionally provide a 121.5 MHz signal which would significantly help search and rescue by planes or official lifeboats.
Ideally, I would like to see:
- a device for which I can get lifejackets to hold it up
- from a manufacturer with long reputation in this area and impeccable engineering (I have a Weatherdock easySplit that I am happy with but they have never before done anything that is supposed to be waterproof)
- having 121.5 MHz and EPIRB capability alongside AIS, ideally with GPS (but at least 121.5 MHz)
- advanced testing capabilities like the ACR PLB tested here recently
The Jotron AIS SART does not really fit the bill for me as it is too large and expensive to be worn on a person (to be fair, it doesn't claim to be "personal"). It is really only suited for use in a liferaft or on a disabled vessel in the process of sinking while a "personal" device such as the easy Rescue can be used in these applications as well. Also, it doesn't have 121.5 homing capability that is reported to be more important than radar (radar will be useless at the last 1/8 of a mile while the position sent as part of a DSC distress call or EPIRB alert should take care of the longer range).
In spring of 2012 I want to start an Atlantic circuit with my family. If no one has a better product by then, I will get the easy Rescue (two or three, actually).
Posted by: Henning at March 12, 2010 7:32 AM
Interestingly, here in Ireland, where they have DSC for over 10 years, they still get virtually no calls to them using DSC. When I call th using a routine dsc call they always are kinda suprised!
In my opinion dsc should have been reserved soley for distress, it was then complicated to support a kind of selective calling system
dave
Posted by: DAve at March 12, 2010 8:17 AM
I still hold out hope for DSC, Dave, but you may be right.
Thanks, Henning; it seems like you've thought about this subject a lot. I'm curious what you think of GPS/DSC/VHF handhelds for man overboard duty. They are still bulky, but can set off a loud alarm on the mother boat and on nearby boats, even a charted location on some systems, plus they have more power than these AIS SARTS, and they're useful for lots of things besides MOB distress. I'm also curious if WeatherDock explained how the easyRescue would set off an alarm. Did they just mean a CPA alarm, which might be shaky for MOB situations (depending on how a boat's AIS plotter is set up), or are they talking about a special AIS SART alarm that has to be programmed into all the AIS target plotters?
Posted by: Ben at March 12, 2010 12:38 PM
Ben: In fact, I haven't thought of a handheld DSC VHF for man overboard duty a lot. For years I wondered why no one made a handheld DSC VHF and I have only learned about it through Panbo recently. I asked the Icom sales rep at boot Düsseldorf about any plans for a DSV VHF and was told "none". So I have a Standard Horizon HX851 down on my shopping list.
So far I have seen these uses for a handheld VHF: take it along in the dinghy if the outboard fails and you're beginning to drift out to sea, call the mother ship to find out how many rolls I should bring for breakfast and communication in a rescue situation such as from a liferaft. DSC will help with the first two uses.
AIS immediately made sense to me because you can see it on the chartplotter - better even than a 121.5 homing device which only gives direction not distance. I assumed there would be a special icon for this type of target (I have read about plans in Germany to replace navaids with a virtual version based on AIS. The physical buoy is no longer there and an AIS signal is broadcast from a transmitter on shore nearby providing the former location of the buoy. These would have a special icon, too).
I wasn't told at boot about how alarming is implemented with the easy Rescue (probably because I didn't ask). I just compared it with a 121.5 homing device which doesn't have alarming either.
DSC is certainly good at alarming although with widespread use (in Germany), false alarms are commonplace (supposedly they have increased 8-fold because of DSC). I frequently have to cancel (silence) a DSC alarm when we are on the water. But I guess it wouldn't be a problem to check around if anyone may have fallen overboard while I do it.
The position indicating capability could be a problem, though. I have a Simrad RS52 dual station that is only two years old (it has SimNet so must even have NMEA2000). I heard or read that it doesn't support "buddy boating" - automatically replying to a DSC position request and sending the sentence with the position of the buddy boat on NMEA0183 or 2000. I don’t know and cannot find out right now if it can output on the bus the position of a DSC distress call. That would be a good thing in any case and I will look into it and consider it when deciding on the PC/Chartplotter solution.
There is also the issue of our two year old daughter who is the most likely crewmember to fall overboard. Even last season at one and a half she climbed up the companionway and out of the cockpit onto the side deck unnoticed on one occasion (though we try to keep her shackled to jack lines). I couldn't teach her to press the distress key on the HX851 when in the water and hold it for 5 seconds with any reasonable hope of success. Although, come to think of it, that is exactly what I tried to teach her not to do on the cockpit station of the RS52... But then, the easy Rescue must also be manually released by removing a plastic cradle that frees the antenna.
There is no form of SART (search and rescue transponder) function in the easy Rescue.
Posted by: Henning at March 12, 2010 5:40 PM
I stated the incorrect model number for the Simrad DSC VHF. The correct model is RS82. I downloaded the manual and learned:
- the following NMEA0183 sentences are read as *input*: GGA, GLL, RMC, ZDA
- there is no NMEA output whatsoever
- there are 2 SimNet connectors but no mention what data is read from the SimNet (NMEA2000) and what is written. Specifically, there is no mention that any is written at all.
- There is an "iDSC" connector that is referred to as an output and that is physically identical to the NMEA0183 connector. The following information is given for this port:
"12.2.4 iDSC output
The RS81/82 is designed to integrate with other Simrad equipment,
which enables DSC call information to be displayed on
the 33, 42 and 52 series Chartplotters.
Connect the iDSC input terminals of the chartplotter to the terminals
marked “iDSC” as shown (Fig 12.7):"
Maybe I should connect a PC with Hyperterminal to it and find out if there is any NMEA0183 data on it (I will use a RS422 to RS232 coupler with optical protection). This will have to wait until the mast is back on the boat and I find someone to call me on DSC or someone to send a DSC distress call... ;-)
Also, I guess I should query Navico Germany about this. This might also take a while as I want to use my special contact but I will post any information here that I might get.
Posted by: Henning at March 13, 2010 4:17 PM
Regarding Jotron Tron AIS-SART:
Please see
http://www.jotron.com/admin/images/viewresource.asp?aid=2237 about how to test and appearance on ECS/ECDIS (Chartplotter)
Posted by: Fred at March 15, 2010 3:31 AM
Thanks, Fred. The USCG's Jorge Arroyo also sent me IEC62288 documentation about what AIS SART and AIS ATON icons will look like on IEC compliant displays. Plus he explained that the "AIS SART signal burst is actually a combination broadcast of an AIS message 14 (Safety related text message stating “SART ACTIVE”, nominally every 4 min.) and an AIS message 1 (Class A Position Report with a nav status = 14 , 8 per minute); both of which should be readable by all existing AIS systems."
Which is all well and good, but, geez, there are a lot of AIS transponders and target plotting programs today that still haven't been updated to understand the Class B Static Data message that was written at least four years ago (I think). Plus I'm not sure how many recreational AIS displays can show Safety Related Messages, or what any will do with Navigation Status #14, which is currently listed as "reserved".
I suspect that it will be a while before many vessels will see an AIS SART as anything more than an unknown target. But that's way better than nothing, of course, and in most real world situations vessels and SAR folks will be looking for the target because the distress was broadcast in other ways.
Posted by: Ben at March 15, 2010 11:10 AM
