In the past few years, commercial shipping vessels have been required to broadcast a vessel position “transponder” similar to those used by aircraft. The system used is called AIS (Automatic Identification System) and uses GPS for position data, but also broadcasts other important data such as ship name, course, speed, and more. The system allows vessels at sea to have a much better awareness of other ships and, in particular, helps avoid the potential of collisions as the seas get increasingly more crowded (especially in ports).
Some academic researchers have been running a web site called MarineTraffic.com that shows the positions of ships around many ports around the world. They rely on a community of data collectors who simply need an AIS receiver and an Internet connection to provide data on ship positions for a given port. A number of similar sites have offered such data on the Internet before (for example, I mentioned VesselTracker.com a couple of years ago). Some of the vessel position report sites are only available on a subscription basis. But, MarineTraffic.com is the largest collection of data I’ve seen and its available for free.
The current MarineTraffic map shows over 10,000 ships. The positions of the ships may be up to 1 hour old, but are otherwise near real-time. Their primary interface is Google Maps which lets you zoom in to see more detail, but only shows a summary of the position data when zoomed out. Clicking on a region zooms you in to show the vessel positions (and headings). Clicking on a ship placemark can give you all kinds of interesting information including a picture of the ship (if they have it), speed, vessel type, size, draft, destination and more (the amount of data varies per ship).
They also have a Google Earth file 
that lets you view the entire dataset of vessels at once. Google Earth is better able to handle over 10,000 position placemarks at once – so you can actually view the entire data set. Also, with the Google Earth version you will see a link in the placemark that will let you see the recent GPS track of the vessel so you can see part of the route it took to get to its current position.
Even Google Earth can get slowed down some by this many placemarks. The developers could use some KML tools to improve its efficiency. For example, by de-cluttering the number placemarks when zoomed higher. Read the MarineTraffic.com FAQ for more information on their data, research, maps, and AIS.
About Frank Taylor
Frank Taylor started the Google Earth Blog in July, 2005 shortly after Google Earth was first released. He has worked with 3D computer graphics and VR for many years and was very impressed with this exciting product. Frank completed a 5.5 year circumnavigation of the earth by sailboat in June 2015 which you can read about at Tahina Expedition, and is a licensed pilot, backpacker, diver, and photographer.
I envision similar response to the UK google maps. The fearers of change will call this a shopping list for pirates
I thought this use of the data, explaining the current economic crisis, was pretty interesting.
http://blog.foreignpolicy.com/posts/2009/05/07/how_google_earth_explains_the_financial_crisis
Too bad they don’t put out the details for the Gulf of Aden. I guess the pirates will have to get their own AIS receivers.
i found a mark on dry desert near my place (in Saudi Arabia)
i didn’t know ships traveled on dry land 😛
http://img514.imageshack.us/img514/8726/shipondesert.jpg
This is a great resource for anyone interested in merchant shipping, and I have been using the Google Maps version of Marine Traffic for a while now. The GE version does not seem to parallel every feature of the Maps version, or vice versa,, and both are a bit ‘clunky’ in places at the moment, for example the apparent lack of an option to delete a ship’s track on the GE version. Overall, however. the GE version seems ‘smoother’.
Users also need to appreciate that lack of ships’ placemarks may often indicate an absence of volunteers with AIS in an area rather than lack of shipping.
A fascinating aspect is to compare what is currently in a port with what was there when the GE (high res) imagery was taken, which gives an even better idea of the traffic at a port – try Southampton or Genoa.
A great system that allows awareness of other ships and port traffic control.
This is incredibly cool. I have no reason to look at this other than to simply enjoy all the ships *right now* wherever they are. Wonderful 🙂
I found a flaw/mistake theres no Marine traffic around Hawaii. Anyone notice that too?
John: It seems there needs to be a local volunteer that receives the signal in order to be displayed in this overlay!
i guess it’s the same as with the flight data, there’s a 200-300km limit to the data, or they could tap into the central server, if there is one… most ships upload their data via satellite to their HQs…
How Can I Download the Marine Traffic ? That i can See The Exact Posidwtions Of the vessels.
The ship positions are updated on a daily basis, weekily or…
carleen:it seems that it is updated daily. and “weekily” is actually weekly
I am not getting the Google Earth version to display under linux – anybody manage to do that?
I am user of shippingexplorer and it is fine for me.
These new apps are fascinating and are improving all the time. You should try the Sail Me feature on Shipfinder 🙂