EPIRB and AIS

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Cargile

Senior Member
Joined
Nov 7, 2022
Messages
186
Vessel Name
Quasimodo
Vessel Make
Cargile Cutter
About to purchase our 1st EPIRB. I see some are advertised with AIS. Our boat does not have AIS and don't plan on purchasing a unit. I understand an AIS has to be registered with some gov't agency? So of what use is an EPIRB w AIS in my situation? or is it an additional expense? Thanks
 
Both EPIRB and AIS need to be registered. In the US EPIRB with NOAA, AIS with FCC or other approved agency.

EPIRB uses satellites to broadcast your emergency. There are variouis EPIRBs available. If satellite is all the EPIRB has then rescuers get close to you but do not have exact your location and have to spend some time searching for you usually looking for a strobe on the EPIRB.

Some EPIRBs have GPS and or AIS. Either will boradcast your exact GPS coordinates cutting the search time to a minimium.

With a GPS enabled EPIRB as far as I know your coordinates need to go the satellite then be communicated back to the rescuers. With an AIS enabled EPIRB your coordinates will be near real time position broadcast. GPS because it uses satellites is not range limited. AIS uses VHF frequencies and is by it's nature range limited.

You have to evaluate your cruising area and closeness to reescue agencies to make your best decision.
 
Though I have no personal experience with them, a quick read to me suggests a great idea.

Very few vessels, including SAR units, have great or even any direction finding aboard so the AIS included version allows ANY vessel with AIS to come to your assistance quickly if they are AIS receive or transceive.

Worth every penny and the effort to register no matter how complicated.
 
But if you don't register it you have hampered the usefullness. Unregistered is better than nothing though.
 
If an EPIRB is unregistered, SAR will still be alerted but the response may be very slow. Since most of their alerts are false alarms, time is spent vetting the device to see if it is real. With a registered device they will call the registered emergency contact numbers for example to verify you are actually out of the water. Unregistered thew may attempt to contact the last registered emergency contacts, but an unregistered is a second priority.

In my opinion AIS is better in a populated area, more likely to get a quick response. In a sparsely travelled area, AIS is unlikely to be heard.

There is a third category, and that is the satellite messengers (such as the InReach) which fill some of this need and are useful for other things.
 
EPIRB will send signal via satellite to USCG. Unlimited range so perfect of you go offshore.

AIS will send signal to any boat and USCG within VHF range. AIS has not been widely adopted by pleasure boats in some areas so response may be limited but probably OK if you boat in crowded areas.

Any modern marine radio will have DSC and if connected to chart plotter will also send out VHF signal to USCG. Again, VHF is range limited.

And there is always 911 on your cell phone.

If you travel frequently over long distances then all 3 methods should be utilized. If you need help, you need it quickly, so the more methods the better. Obtaining the required MMSI number or registering the epirb is an easy and quick process.
 
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There is AIS and DSC. Both work through VHF transmission. AIS does not transmit a distress call but is highly useful in identifying other vessels and also making yourself seen to other vessels. DCS is usually a part of your VHF radio. The red distress button is one part of it. When the red distress button is pushed it will send a distress signal over your VHF to anyone monitoring that frequency. IE Coast Guard and nearby boats. Very important that you have your MMSI number Pre programmed into the radio so that the signal is identifiable to those receiving.
EPIRB will send distress signal via satellite. MMSI has to be programmed here also. If you are boating in a remote area EPIRB would be my first choice. In less remote areas DCS would be my first choice. Having both can’t hurt.
 
These are pretty new...everyone done their homework? Not sure based on some parts of some posts.....

https://www.hodgesmarine.com/acr285...200315462&utm_content=Shopping - All Products

Acr Globalfix V5 Cat 2 Gps Ais Epirb W/Return Link Service & Mobile App
GlobalFix™ V5 Cat 2 GPS AIS EPIRB with Return Link Service & Mobile App

The ACR GlobalFix V5 EPIRB combines 406 MHz satellite connectivity with Automatic Identification System (AIS) functionality. This means that when the EPIRB is activated not only does it transmit your emergency signal to the global Cospas Sarsat satellite rescue system, but it broadcasts an AIS safety message on VHF-frequencies that can be seen immediately by any AIS-equipped vessel nearby. Other great features include Return Link Service (RLS) technology that provides visual confirmation to the user that their distress message has been received, a 121.5 MHz homing signal, and visible and infrared strobe lights for easy target identification at night or in poor visibility. Another feature is Near Field Communication (NFC) which allows users to monitor their EPIRB using a smartphone App. ACR is the global leader in marine safety and rescue technology and the GlobalFix V5 GPS EPIRB with AIS combines the durability and reliability they are known for with advanced technology designed to speed rescue response time.
 
When I was in the cg and one of the stations would receive a distress signal, IRC these could be satellite but 121.5 not 406mhz. We would launch and once in the general area we would then use df capabilities at a 121.5 mhz.... I'm pretty sure things have changed now with GPS coordinates embedded in the 406 mhz distress message.
 
https://www.yachtworld.com/research...additional homing signal for greater accuracy.

An EPIRB is registered to the vessel and transmits a short burst of data when it’s activated. Most EPIRBs today function on the 406MHz bandwidth and their signal can be picked up anywhere on the globe as opposed to the older and less expensive 121.5 MHz units whose signal was designed to be picked up by airplanes flying overhead. Some EPIRBs include both bands and use the 121.5 MHz as an additional homing signal for greater accuracy. Some also have integrated GPS to broadcast not only distress but also a specific location and they’re called GEPIRBs.
 
There is AIS and DSC. Both work through VHF transmission. AIS does not transmit a distress call but is highly useful in identifying other vessels and also making yourself seen to other vessels.
The AIS MOB beacons broadcast a DSC distress call and also AIS beacon information. In theory, everyone within range will get a DSC distress alert along with the AIS information.
Some also have integrated GPS to broadcast not only distress but also a specific location and they’re called GEPIRBs.

Almost any new EPRIB you buy these days will be 406 MHz and have GPS. For example ACR does not sell one without GPS. A GPS receiver module is <$5 these days, almost criminal not to put one in.
 
There is also one PLB/AIS approved in the US that just went on the market: ResQLink AIS Personal Locator Beacon - ACR ARTEX. The PLB capability (same as EPIRB but with less battery life) alerts the SARSAT/COSPAS system and will provide a distress alert to the appropriate SAR system. The AIS capability transmits the local VHF-FM alert that can be picked up by nearby AIS receivers. Thus you have what is in effect a "global alert" and a "local alert" functionality. The unit also transmits on the aircraft distress UHF frequency which provides a homing signal for SAR aircraft. ACR has the only one so far but I am sure the other PLB manufacturers will get there's soon! The PLB/AIS is also designed to be attached to a lifejacket.
 
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There is also one PLB/AIS approved in the US that just went on the market: ResQLink AIS Personal Locator Beacon - ACR ARTEX. The PLB capability (same as EPIRB but with less battery life) alerts the SARSAT/COSPAS system and will provide a distress alert to the appropriate SAR system. The AIS capability transmits the local VHF-FM alert that can be picked up by nearby AIS receivers. Thus you have what is in effect a "global alert" and a "local alert" functionality. The unit also transmits on the aircraft distress UHF frequency which provides a homing signal for SAR aircraft. ACR has the only one so far but I am sure the other PLB manufacturers will get there's soon! The PLB/AIS is also designed to be attached to a lifejacket.
Thanks, hopefully some will do a bit more research to get the big picture on what is truly available.
 
Transmission of AIS by an EPIRB is a great enhancement. I didn’t realize that was available. So I guess I will stand as corrected / educated. My post was to distinguish the 3 different technologies and their different strengths. Most importantly I didn’t want someone to think AIS would suffice as a distress mechanism. Learn something new every day.
 
I apologize for my shortness and brusk attitude sometimes.

Most posters do their best to post good info. Some not so much as darn near every post of theirs has incorrect info in it.

Most of the time, if I have no personal info on the subject or it's one I haven't been personally involved with, I try a little research before I post. Keeps down the confusion and misinformation.... in addition to creating mindless discussions other posters have to wade through. Even in this case I am not well read on the subject...but my post/links are designed to get truly interested persons tuned in to their own research on the subject.

I do have enough experience to know tidbits about quite a few subjects and know that electronics tech changes every year and be careful to not report only what I knew last year.

Again, just a couple of minutes to double check a post's validity takes only a few minutes. Soapbox.... out.......
 
My understanding is in open ocean, particularly beyond helicopter range, most MOB rescues are done by the boat you fell off of or a boat in your fleet or rally. In this setting AIS is a much more valuable aid than any gps based device. Our harness/pfd set ups have carried both a 24 hour epirb and a AIS but now you can get both in a single device. As well as the personal devices we carried a ship’s epirb. It was in a bracket so could be removed and carried into the liferaft if needed.
Believe in a coastal setting this is overkill and unnecessary expense. Realistically you can set off the personal devices sequentially so get at least 48h even with only two. The majority of rescue occurs with 24 hours. With AIS there’s two things to consider. Can your vessel see the signal generated by a MOB? Can the rest of the world see the signal? In a coastal or near shore (<200nm offshore) setting believe a ships epirb is unnecessary but each personal set up should carry a combined personal epirb/AIS and the ship should have AIS on its own antenna. Appropriate spare connections to allow the ships AIS unit to use the VHF antenna as well. Prior boat had both SSB and KVH satellite comms. Once again if coastal believe both are unnecessary. However if nearshore or open ocean at a minimum would carry some form of satellite communication. Ideally one that could carry both voice and data. My two cents. P.S.-combo personal units are on my Xmas list.
 
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https://www.lrse.com/collections/epirbs-plbs/products/acr-globalfix-v5-category-i

https://www.lrse.com/collections/ep...ps-personal-location-beacon-plb-450-w-ais-rls

The second of these devices are personal epirb offering gps locators for at least 24h and AIS. Several vendors offer similar. Apparently things have changed since you retired. I continue to believe they are more than adequate for coastal near shore environments. My viewpoint is based on both professional and amateur opinions I’ve garnered.
 
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As an aside would give a +1 to ocens for offshore communications needs. Personally had the best experience with KVH, second with iridium products and not so much with globalstar. Understand starlink changes things now. But if going nearshore would add some form of satellite communication independent of a SAR request. Feel it’s a necessity if offshore. Believe in certain scenarios having that may even prevent the need for further outside help. Have used voice satellite to help me work through things like navigation instruments troubleshooting and repair, watermaker troubleshooting, medical issues such as obtaining salient information about crew from loved ones. Text is wonderful but when stressed or it’s real bumpy voice is very helpful. Also a +1 to LFSE. Talking with them is always an education. They service pros and amateurs so get sufficient feedback to make appropriate recommendations.
We are in the process of replacing all our PLBs with combo devices. So far the ACR device linked above seems the best bang for the buck for our current program.
 
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Transmission of AIS by an EPIRB is a great enhancement. I didn’t realize that was available. So I guess I will stand as corrected / educated. My post was to distinguish the 3 different technologies and their different strengths. Most importantly I didn’t want someone to think AIS would suffice as a distress mechanism. Learn something new every day.

The combined EPIRB (or PLB) / AIS were literally just approved (in the US) and hit the market only in the past couple of months. But your review of the the 3 very different technologies (and their pros and cons) is still very valid as many people will not have the combined units (if at all) or will still make the decision between different technologies.
 
Another way to skin the cat is to keep your existing PLBs and add this handheld DSc vhf with AIS
ICOM IC-M94D AIS & DSC VHF RADIO.
Keep it charged and ready for the ditchbag. Sure a ships Epirb will go 48h but coastal/near shore likely not needed and if so set off the PLBs sequential. Current personal units tell you the request was received. Then the radio when you hear the helicopter or see the boat. Of course what you do is situationally specific. Likely radio battery life is sufficient in most coastal settings. Talking with active CG members think it likely more combo units will become available at both ship and personal levels and the transition to combo units will occur.
 
Well that is a lot of good info - thanks!. Our boating is mostly inshore/nearshore Florida. I believe our situation would be best served by an EPIRB w GPS. Our VHF radio has DSC. The antenna tip is >25' above the water. For VHF the range is really good. As AIS uses VHF line of sight frequencies could an EPIRB w AIS be connected to our 25' antenna? or does it use the EPIRB antenna?
 
These are pretty new...everyone done their homework? Not sure based on some parts of some posts.....

https://www.hodgesmarine.com/acr285...200315462&utm_content=Shopping - All Products

Acr Globalfix V5 Cat 2 Gps Ais Epirb W/Return Link Service & Mobile App
GlobalFix™ V5 Cat 2 GPS AIS EPIRB with Return Link Service & Mobile App

The ACR GlobalFix V5 EPIRB combines 406 MHz satellite connectivity with Automatic Identification System (AIS) functionality. This means that when the EPIRB is activated not only does it transmit your emergency signal to the global Cospas Sarsat satellite rescue system, but it broadcasts an AIS safety message on VHF-frequencies that can be seen immediately by any AIS-equipped vessel nearby. Other great features include Return Link Service (RLS) technology that provides visual confirmation to the user that their distress message has been received, a 121.5 MHz homing signal, and visible and infrared strobe lights for easy target identification at night or in poor visibility. Another feature is Near Field Communication (NFC) which allows users to monitor their EPIRB using a smartphone App. ACR is the global leader in marine safety and rescue technology and the GlobalFix V5 GPS EPIRB with AIS combines the durability and reliability they are known for with advanced technology designed to speed rescue response time.

This looks very nice. I was going to get one except they aren’t available yet. I guess they will become available in a month or so.
 
Go with an EPIRB/AIS Combo

While new and more expensive, if I am ever in a situation where I need to to activate an EPIRB, I want to maximize the probability that I and any crew are rescued in the shortest possible time. Based on this, a combo is the one I would go for. The AIS registration process is very simple and should be able to be completed when registering the unit with NOAA.
 
This looks very nice. I was going to get one except they aren’t available yet. I guess they will become available in a month or so.

ACR website says orders for the ACR Globalfix V5 Cat 2 GPS AIS EOIRB will shIp the week of 3/20/23, so dealers should have them soon. You can also order direct from ACR.

GlobalFIX V5 AIS EPIRB

The PLB version has been available for about a month or so.
 
Well that is a lot of good info - thanks!. Our boating is mostly inshore/nearshore Florida. I believe our situation would be best served by an EPIRB w GPS. Our VHF radio has DSC. The antenna tip is >25' above the water. For VHF the range is really good. As AIS uses VHF line of sight frequencies could an EPIRB w AIS be connected to our 25' antenna? or does it use the EPIRB antenna?

The EPIRB antenna is integral to the unit as it is designed to "take with you" or float free when you abandon ship. Since the signal is sent to a satellite, I don't see an advantage to a higher mounted antenna. All that is needed is a clear sky view. Same for GPS reception.

As you mention, perhaps a higher antenna would give a better AIS range (for the combined unit), and longer range homing signal on 121.5, but I don't think that is an option on the combined EPIRB/AIS being discussed.
 
Wouldn’t be too worried about antenna height and range . The gps gets them in the neighborhood and the AIS at the right street address. Suspect with the AIS they will be looking down at you from a helicopter or even a ship. Don’t think curvature of the earth comes into play nor getting maximum line of sight from a high antenna as the other antenna should be high enough. Suspect even if both antennae are low given close proximity now available from gps other than intermittent signal from wave height interference a handheld AIS would be adequate. During the ocean races crew fall off their boats and are recovered by their mothership utilizing AIS signal attached to their harnesses. Can’t think of an antenna lower than that. A hockey puck on a pulpit rail is sufficient for gps.
Love the concept of gps and AIS as they complement each other beautifully.
 
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I would think that both the EPIRB (if a GPIRB) and the AIS are transmitting a WAAS corrected GPS positions to within a few meters or whatever the accuracy.

I would also think both are getting positioning from the in device GPS receiver.

The advantage of the mixed device is that any vessels (AIS equipped) within the AIS transmitter range can respond immediately where the EPIRB signal has to go through a more convoluted system and relayed to any vessel or SAR asset from a rescue coordination center.

But the device relays the same position either way.
 
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I give up. Yes I know that. But I also know over the last few years more and more sailors are now carrying personal AIS rather than gps only PLBs. Position isn’t everything. Getting the person out of the water quickly and safely is. Given just about every MFD gives you a AIS position on your screen in real time can you accept it greatly enhances odds of recovery of a live person? Even with drift or in a raft. In the past on a small boat you were taught to hit the MOB button, drop a MOM then search. Sure that’s still true but having the person in the water actively transmitting a AIS signal is a game changer in my mind. You can look at your MFD and go to where they are now.
PSN I’m not a professional SAR but I’ve been on the other side of this for 35+ years thinking about how to keep me and crew safe. Say whatever you want they definitely compliment each other.
Looking at the forest not one tree OP asked how to spend his money.
Have a handheld and ships DSC vhf and know how to use it
Get a personal AIS/gps unit for your self and crew
Get a raft appropriate for where you may find yourself.
Have a ditchbag appropriately stocked.
If offshore have some form of Satphone and ships epirb.
Then you’re covered for fire, sinking, medical emergency and MOB. Ships epirb doesn’t help much with MOB to my thinking.

As said we’re replacing our PLBs with the linked combo units as cruising kitty allows. Being coastal now I’m not replacing the ships epirb battery and will depend on the combo units. Now that’s my decision without any nitpicking. Given the ACR unit isn’t that expensive but still a boat buck for two think the OPs and my money is better spent there then on a ships epirb. Outside helicopter range definitely necessary but doesn’t sound like he’s crossing oceans. Have fun nitpicking.
 
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I have one EPIRB on my vessel. I plan to add a second at some point, but between a bunch of radios of location-transmitting radios of various kinds, a satellite phone, etc, a second EPIRB just hasn't been a priority.

The unit I have is one of these:
https://defender.com/en_us/mcmurdo-category-1-smartfind-g8-automatic-epirb-with-ais-23-001-501a

-- The 121.5 MHz is the old, nearly obsolete marine/aviation distress frequency. The satellites that once monitored it are no more. It can't encode location information. Even at its peak of utility, it was rough. It could be localized to about a 15-17 mile radius -- a nearly 800 sq-mile search area. Having said that, plenty of aircraft (and perhaps commercial vessels) still monitor it to this day.

-- The 406 MHz signal is the current beacon frequency and is received by satellites as well as locally. It can be localized to a radius of 1-3 sq-mi for a ~25 sq-mil search area. If GPS is available, it can be localized within a few hundred foot radius,

-- With an internal GPS available, the 406Mhz signal, which is digital, can send out the GPS coordinates. GPS can often put the location within a 100 yard radius, which is a search area of ~0.005 sq miles. Much better.

-- The AIS transmitter is dual channel, but only 1W. This is probably to minimize power draw and maximize useful lifetime. None-the-less, the range is probably only a ~1mi radius. And, maybe less -- if the EPIRB is floating in the water, the VHF is going to have a really hard time getting past swells. So, a very nearby boater (more likely ship) with AIS integrated into their MFD could find you this way. But, other than in busy waters, it may just help someone nearby look the right way. At least in my thinking.

Personally, I like the idea of it having AIS, but I am much more comforted by the internal GPS and 406Mhz signal. Well, that and the fact that it can self-deploy.
 
Use case turns out to be interesting, I think. For a PLB, I'd really want AIS. Especially for a race. The person who goes in the drink is right near a bunch of boats paying attention. The goal is for the vessel to find the nearby person.

If the case of a long delivery or cruise or Bahamas crossing in the event of a major medical issue or vessel issue, the goal is to find the vessel and it isn't known if other vessels are nearby and that helicopter has to find its way there. It isn't clearnto me how much sending the GPS location via AIS is helping any more than sending it by satellite. The officials get it and can use it or relay it.

AIS PLBs are great. They are also on my list. If I had a sail boat, I'd have a bunch already.

Just my thinking -- among much thinking around here!
 
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