I just loaded this new app onto my phone and used it last weekend for a trip to Alderney and back. Great results no missing parts of the voyage.
I have always been disappointing by the coastal coverage of AIS using class B transponders round the UK, as the results are very varied depending on how many and how good the shore based receivers are that transmit the information to the likes of marinetraffic.com
This new FREE app is great, it takes your location, speed, & direction information from your phone, you type in your vessel MMSI & details, then when you are in range of cellular data / wifi /3G the info is passed onto the marinetraffic.com website. Turn the app on when you leave port, turn it off when you arrive. Very simple.
This is not AIS, other vessels in your locality wont see your position
, but anyone looking on the marrinetraffic.com website can see it historically, so really good when round doing a Round Ireland or Round Britain voyage and having a live map.
For further details see mAIS - iAIS for Marine Traffic - Report the position of a vessel using a mobile smart phone on board