AIS and vessel tracking

[csoule13]

So, S/v Discovery is currently somewhere in the Atlantic en route to her new home in Rhode Island. The Captain has a new spiffy VHF with AIS, and I have the MMSI number. His last words before heading out past cell range was "Hey, I bet you can track us online!"

We can not, in fact, seem to do that.

There's a number of websites that show shipping traffic on a map, and have MMSI searches to find vessels. Discovery is not on them. So, either she's sunk, or there is a misunderstanding on my end.

Any experience here with this type of stuff? Am we just overestimating what information is publicly available? It's a nice to have, but it would also put some of the support crew on shore at ease, y'know?

Thx,
Chris

 

[nquigley]

I don't think that's possible via AIS. I think that real-time tracking needs a satellite-based system like InReach, with a service to provide tracking updates made available by the subscriber to chosen friends/family.

 

[csoule13]

I don't think that's possible via AIS. I think that real-time tracking needs a satellite-based system like InReach, with a service to provide tracking updates made available by the subscriber to chosen friends/family.

Thanks, that's my assumption, but worth a shot. Seems like a good use for something like the Spot Trace. For $50 for the unit and $15/mo for service plan, that's a pretty cheap way to keep the less salty members of the on-shore crew happy. Should have thought of that a month ago, oh well.

 

[JPS27]

If I follow what you are saying/asking, a VHF with AIS might only be receiving not sending. That's waht I have. The MMSI number is important when you hit the DSC button in an emergency. I'm a novice in these areas though...

 

[ddoles]

I had this same observation with AIS and on line systems. What I find with my AIS is if I am in a heavy traffic area like NY Harbor my boat is visible with all relative information available through a number of online sites. When I venture off to less populated areas, or certainly at sea, I am no longer visible on these sites. I believe these online systems pick up the AIS feed from shore based receivers and the coverage is focused on busy harbor areas. Outside busy ports they seem to get some feed, but mostly from ships carrying class A AIS. Most recreational vessels will have class B AIS.

 

[Christian Williams]

AIS transceivers transmit using VHF. Shore based stations can make that wide, which is why my boat sometimes shows up en route Catalina. But offshore, not. I believe the signal can piggyback on commercial ships, for longer range, and also maybe from fixed nav aids--the nonphysical kind.

Kind of a mystery in the real world, because I have seen ships 50 miles away or more when offshore, and nav aids 100 miles away.

 

[csoule13]

Thx everyone. Captain and crew of Discovery got their ass handed to them at the mouth of the Delaware River and spent a night recovering at a dock in Atlantic City. Currently en route to Block Island before the blow comes in tomorrow evening. I think a Spot is on the list for a Father's Day gift this year.

 

[toddster]

I have not looked into the details but I believe that to unlock the details of satellite-detected AIS signals, you need to buy a subscription to the service. Otherwise the "Marine Traffic" map just shows "tug" or "pleasure vessel," etc., with no other data. I seem to recall that you subscribe to a specific group of mmsi numbers : "my fleet." For example, during Jeanne Socrates recent circumnavigation, several members of other forums subscribed to follow her AIS signal.

 

[mjsouleman]

Closing the loop on this discussion,

MMSI was useful when we contacted the Coast Guard for identification while off the Long Island coast. The Standard Horizon GX2400 AIS was able to detect vessels up to 21 miles in 360 directions, also helpful. What was odd to this newbie were commercial vessels that did not broadcast an AIS signal. Two standout. the first was in the Chesapeake and Delaware Canal and the second was about 2 in the morning 30 miles off shore when the captain identified the red/ and double white light tower of a (barge?) off to starboard, also not showing on AIS.

Note: Shennicock Bay, Long Island is "shallow" and dangerous to enter. Be advised to enter from the East. Some how we managed to get into a marina under a super moon. Most of 4 days were spent in 2.5 feet of water and 4-5 at high tide. The day after the storm an other sailor was able to sail into a shallow sheltered space nearby.

Mark "Souleman" Soule

 

[rbonilla]

imho the garmin in reach unit will do a nice job tracking...once you
pay $ and activate the feature....shows a nice map - worldwide..no voice..just txt,
lat & long position info....and, you can "drop e bread crumbs" every hour, or so for speed
and distance ++ never hear of online ais...

 

[paul culver]

AIS is being engineered to light up NAVAIDS on your screen. Instead of putting a transmitter on a buoy for instance, a shore based station can broadcast the buoy's position. In fact, its possible to create virtual NAVAIDS where none physically exist, perhaps to warn of a newly developed hazard. Cool stuff.

 

[toddster]

Yeah, some of the features around here have been showing up on AIS for a couple of years. But not always the same ones. The hydroelectric dams show up sometimes. Now, some of the range markers (but not all) show up. I guess they're experimenting.

For a while there was a strange one shown several miles inland that appeared to rapidly move along about a 1-mile track, over and over. I guess it was some sort of directional marker, but the direction of what, I don't know. Haven't seen it for a while.

Wow, I just looked at "Shipfinder" and they want $60 a month (and up!) to see real-time info now! MarineTraffic is still showing realtime data in the free version. But for my immediate area, that often depends on whether the volunteer ham who operates a ground station is up and running.

 

[paul culver]

For a while there was a strange one shown several miles inland that appeared to rapidly move along about a 1-mile track, over and over. I guess it was some sort of directional marker, but the direction of what, I don't know.

Yep, a pointer to the local Hooters I bet.