AIS question for the experienced

[jackdale]

Originally Posted by Pleiades

In our context “local” meant transmits MOB info to all AIS ships in the vicinity of the vessel to which the PLB is registered by itS MMSI number.

PLB do not transmit locally, they transit through the same satellites as EPIRBS. PLB do not have MMSIs, they are registered with same beacon registry as EPRIBS.

Personal AIS transmits locally and enables the casualty’s position to be displayed on the chartplotter of your own boat and others nearby, including lifeboats once near the scene.

By contrast, personal locator beacons transmit their primary 406MHz signal only to a remote rescue coordination centre. This can be helpful in raising the alarm and in deploying search and rescue assets, but doesn’t help your own boat and others around you to locate a person in the water.

Personal locator beacons transmit a secondary signal on 121.5MHz, which is helpful for lifeboats homing in on a casualty, but other vessels are rarely equipped to receive this signal.

https://www.yachtingworld.com/yachts...boating-137237

I own one of each.

[Pleiades]

Am I using the term PLB incorrectly?
In my world PLB = Personal Locator Beacon
and we are discussing the differences between EPIRB PLBs and AIS PLBs.
In my case at least (I have both types on my PFD) my AIS PLB is registered to my boats MMSI number. I know this because I programmed it. The AIS PLB communicates with satellites on 161.975/162.025MHz+/-500 Hz at 9600 baud. DSC (which is what I meant by “local”) transmissions to the parent vessel’s MMSI are on 156.525 MHz at 1200 baud.
EPIRB PLBs and EPIRBs transmit to satellites at 406MHz.

[jackdale]

Originally Posted by Pleiades

Am I using the term PLB incorrectly?
In my world PLB = Personal Locator Beacon
and we are discussing the differences between EPIRB PLBs and AIS PLBs.
In my case at least (I have both types on my PFD) my AIS PLB is registered to my boats MMSI number. I know this because I programmed it. The AIS PLB communicates with satellites on 161.975/162.025MHz+/-500 Hz at 9600 baud. DSC (which is what I meant by “local”) transmissions to the parent vessel’s MMSI are on 156.525 MHz at 1200 baud.
EPIRB PLBs and EPIRBs transmit to satellites at 406MHz.

Yes you are using the term PB incorrectly.

A personal AIS is not a PLB. PLB's transmit on 406 mHz and are registered with the registry to a person. AISs have an MMSI, PLBs do not. EPIRBs and PLBs also differ. EPIRBs are registered to a vessel and have twice the battery power of a PLB. EPIRBs and PLBs communicate with RCCs. Personal AISs communicate with nearby AIS receivers.

A personal AIS does NOT communicate with satellites. It communicates with nearby AIS receivers.

AIS transponders and receivers use two VHF radio frequencies.

Unlike a personal locator beacon, which signals orbiting search and rescue satellites, AIS sends an alert message within seconds to all local vessels with an AIS receiver and/or AIS-enabled plotter. Plus, the DSC alarm on your vessel’s VHF radio can also be signaled to make first responders aware of what’s going on.

[HeywoodJ]

There was a discussion of the term “PLB” in the recent thread on the Sydney-Hobart race where a number of “PLBs” were accidentally activated.

https://www.cruisersforum.com/forums...ml#post3548694

PLB is a COSPAS-SARSAT term for a non-boat-registered 406 MHz beacon:

PLBs are portable units that operate much the same as EPIRBs or ELTs. These beacons are designed to be carried by an individual person instead of on a boat or aircraft. Unlike ELTs and some EPIRBs, they can only be activated manually and operate exclusively on 406 MHz.(emphasis added). And like EPIRBs and ELTs all PLBs also have a built-in, low-power homing beacon that transmits on 121.5 MHz. This allows rescue forces to home in on a beacon once the 406 MHz satellite system has gotten them "in the ballpark" (about 2-3 miles).Some newer PLBs also allow GPS units to be integrated into the distress signal. This GPS-encoded position dramatically improves the location accuracy down to the 100-meter level…that’s roughly the size of a football field!

Unfortunately, several vendors advertise their AIS and DSC devices as “PLB” and so the term has come to be used generically.

[cohort]

A VHF with DSC and AIS (receiving) is too easy and inexpensive not to have in 2022. Same goes for a PLB. If the skipper can't (or won't) spring for a new VHF with these basic capabilities, maybe you better take a hard look at what else is not on the boat, or what else is not working, or is old enough to fail enroute.

[donradcliffe]

While I deliver boats without radar or AIS, I prefer to have them both. It's not practical for me to carry my own radar, but I bought the Icom IC M94D handheld with a built-in GPS/DSC/AIS.

As I have said before, I'm not happy with the product as it was produced, but its shortcomings could be easily rectified by Icom if they were given some incentive. If any of you happen to visit the Icom booth at a boat show, tell them you are interested in the product, and ask them why it can't be used while it is being charged and why it seldom recognizes the long AIS packet which gives the ship's name, even at a range of less than 5 miles.

BTW, it was a lot easier to get an MMSI for the handheld from the US Power Squadron than from BoatUS.

[Bmorgan562]

Originally Posted by donradcliffe

While I deliver boats without radar or AIS, I prefer to have them both. It's not practical for me to carry my own radar, but I bought the Icom IC M94D handheld with a built-in GPS/DSC/AIS.

As I have said before, I'm not happy with the product as it was produced, but its shortcomings could be easily rectified by Icom if they were given some incentive. If any of you happen to visit the Icom booth at a boat show, tell them you are interested in the product, and ask them why it can't be used while it is being charged and why it seldom recognizes the long AIS packet which gives the ship's name, even at a range of less than 5 miles.

BTW, it was a lot easier to get an MMSI for the handheld from the US Power Squadron than from BoatUS.

Thank you Don, for both replies. Ais/OPO. IVE ALREADY PURCHASED the ICOM. ITS ENROUTE AS IS AN EXTRA BATTERY MOOT POINT OF COURSE(cancelling). spent too much time yesterday. trying to figure the ins and out of that charging sensation they have. i was resigned to purchase another dock, cord (also loot point )and battery. thanks for the power squadron heads-up. !

[GrowleyMonster]

AIS. Get it. It is well worth it to install a full transceiver setup for that passage. Further, you can leave it on and not seriously impact your batteries. Modern radars are not too bad in that regard but you still don't want the set fully powered up 24/7. Eyeballs are more important, but AIS and radar both definitely have their strong points and are valuable tools.

Lack of AIS isn't really a good reason to not make the passage, but it just seems rather silly to not install it. If the budget won't allow for AIS then maybe the sailing on a shoestring thing is stretching the shoestring a bit too far.If the crossing isn't affordable, then compromising on safety is not the way to make it so, IMHO. YMMV. Good Luck. Hope this works out for you. It probably will. It might not.

[Bmorgan562]

Ok, we made it, 20 day passage from Oceanside, Ca. via Guadalupe island, to Hilo, Hawai’i. And believe me I could write a fair size book about the experience ( character count being limited here). I’m kicking around titles. Currently shying away from “ My passage aboard an anxious and unsure christian supremests boat”. as i don’t want to offend anyone out there trying to find their way. Just wanted to speak about the M94D AIS/GPS/DSC Marine Handheld Radio. Very susceptible to even mist, it alerts visually and with sound. over and over like your about to be run down, which was the most annoying aspect of it. second was the inability to charge it while the unit was on ( risk of sure catastrophic damage). and the inability to charge a back up battery to replace the used watch battery. Multiple times throughout the Pacific i used the dsc function( so awesome!!!!) to speak to and navigate many ships the most friendliest and well welcomed voices. So as far as the voyage, thought i did my due diligence to vet this particular Uscg 10t Captain and his boat. Well the boat made it Thank you Stan Huntingford. Sometimes you eat the bar and sometimes the bar eats you. Well I made it. Want my own boat.

[Jim Cate]

^^^^^
Thanks for the update! (and for the warning about the handheld unit). Your untold story reminds me that the two most dangerous things one can do on a boat are: 1. Crew for an unknown skipper and 2. Take on unknown crew on your own boat.

Glad that you came out unscathed and with some new knowledge.

Jim

[Bmorgan562]

Originally Posted by Jim Cate

^^^^^
Thanks for the update! (and for the warning about the handheld unit). Your untold story reminds me that the two most dangerous things one can do on a boat are: 1. Crew for an unknown skipper and 2. Take on unknown crew on your own boat.

Glad that you came out unscathed and with some new knowledge.

Jim

Thank you Jim. 👍😊

[Hoodsail]

Originally Posted by Jim Cate

^^^^^
Thanks for the update! (and for the warning about the handheld unit). Your untold story reminds me that the two most dangerous things one can do on a boat are: 1. Crew for an unknown skipper and 2. Take on unknown crew on your own boat.

Glad that you came out unscathed and with some new knowledge.

Jim

Jim, fully appreciate the risks of your two most dangerous situations as a small sailboat off shore is an environment that doesnt lend itself to private space or room for much if any error. BUT, I had the good fortune to be the instigator of #2, taking on 2 unknown crew for 6 and 12 day passages. We met before and sailed once on my boat before going offshore. Both crew were accomplished sailors, one with more experience than me as the erstwhile skipper. They were both stalworth fellows who handled "robust weather" and the unexpected breakage without an issue...not certain how their evaluation of me via your #1 scenario would sound but I would hope at least passable. thnks

[JPA Cate]

Yes, you do not need AIS. If you and the others are attentive watch keepers, you can get out of the way of fast moving cargo vessels. AIS would give you earlier warning than the mark one eyeball; however, most radars will pick up commercial vessels at 16 miles at least--steel cargo ships send back strong returns. Not if it is pouring rain, maybe not until 8 mi, then, but the return is a large one, you'd notice it if you've any experience with radar. Suggest you spend some time with it while you leave, looking at the land, and boats, and ships, if available to learn what the returns look like.*

AIS is nice to have, because it gives you the names of the vessels, so you can hail them directly, rather than "Commercial vessel located at position x deg N, y deg W." And it gives you their range and course and speed, so you can figure out where they want to be and you can go elsewhere. Always mention that you are a sailing vessel. Some of them have recorders that will record their response (or lack of it) if it comes to litigation.



*note, we were using celestial when we sailed SF - HI and return. We didn't have sat/nav till 3 yrs. later. There was no AIS, and that boat didn't have radar, either. One rainy night, I saw ship lights astern at some distance from us. I put out a blind call on the VHF --the only one I'd ever done--, just to let the traffic know we were there. It was most gratifying to see them change course to avoid us. Not all ships do that.

Ann

I apologize for the first paragraph, hadn't finished reading all the posts, yet. Mea culpa

[goboatingnow]

Transmit AIS is much more useful then that as it’s gives commercial shipping advance warning you are a WAFFI and they will change course to comply with their COKREGS obligations. I’ve seen commercial shipping alter course over the visible horizon to avoid yachts.

[MC2019]

I carry a AIS transponder, vesper 8000 in my delivery business. Saved our bacon numerous times, reprogram it for each vessel and cary a handheld VHF programmed with the MMSI number. Have the programming tool on my laptop to change the information when moving to another vessel. Yes I cary antennas with me