We have had a number of earlier posts discussing the Automatic Identification System (AIS) for recreational sailors and like all technology it has raced forward at a tremendous pace, to the point now where there are apps available for your smartphones that can be used as a fall back situation in an emergency if your hard wired AIS installation has failed.
They are not to be used in place of a full AIS installation and the app suppliers are quick to warn against this practice in their installation notes. However, they are a useful device for locating other shipping in your area, the course they are on, speed and possible collision information.
A recent incident of how useful they are occurred in South Africa with a yacht avoiding collision with a merchant vessel in fog. These sailors were using the 'Boat Beacon' and the following story is described in www.sail-world.com :
|  | 
| Vessel and buoy in fog | 
'Boat Beacon, a very inexpensive App you can have on 
your Smartphone, has helped some South African sailors to avoid a collision 
according to the story they told after the incident. As reported recently by 
Afloat, the two sailors were on a delivery trip between Cape Town and Durban 
when their AIS equipment on-board failed and they found themselves in thick 
fog. 
They resorted to the only alternative they had, their Boat 
Beacon app on their smart phone. This did the job reporting that there was a 
container ship advancing on them. The only problem was, unlike the AIS, they 
could not tell the Closest Point of Approach (CPA), so in the foggy conditions, 
they still had some anxious moments. 
Nevertheless, with heightened 
awareness, the collision was averted. The developers of Boat Beacon have since 
said that they will add the feature of CPA to the App. 
In fact, Boat 
Beacon was designed and developed by Pocket Mariner’s sea-faring CEO after his 
own near miss at sea – and provides an affordable and reliable AIS-based 
collision detection system for iPhone and iPad or Android smartphones and 
tablets. 
|  | 
| Boat Beacon Display | 
|  | 
| Boat Beacon Display | 
Features: 
Real time 
map view of your boat and boats near you via AIS. 
Over the horizon collision 
avoidance and alarm using Closest Point of Approach (CPA) 
CPA calculations 
and AIS position updates continously in background 
Compass mode to sight 
ships on the map 
Current Speed, Course and GPS location 
Share your 
location with friends and family (iOS only at present) 
Man Overboard 
tracking (iOS only at present) 
Anchor Watch and Theft Alarms (iOS only at 
present) 
Ship to Ship instant messaging – chat with other Boat Beacon boats. 
(iOS only at present) 
Magnetic or True North setting. (iOS only at present) 
MMSI numbers to contact nearby boats on via VHF. 
With transmit 
enabled your boat will appear on other Boat Beacon devices. If you enable AIS 
sharing and have an MMSI number your boat will also appear on live AIS traffic 
sites and their associated mobile applications, eg: 
AIS Hub 
Marine 
Traffic 
Ship finder 
Boat Beacon supports iPhone, iPad & Android 
Requirements: 
iPhone or iPad with GPS. e.g. iPhone 3GS, 4, 5 or 
later, with an active Internet connection. 
Android device with GPS and 
an internet connection. 
Fortunately Cellular data coverage extends up to 
15 miles out to sea and most popular boating areas are covered.
NOT FOR 
NAVIGATION 
This program is distributed in the hope that it will be useful, 
but WITHOUT ANY WARRANTY. Boat Beacon should not be relied upon to determine 
precise locations, proximity, distance, or direction or make navigational 
decisions. The author assumes no liability for damages arising from use of this 
program.
AIS data is sourced from a variety of voluntary shore stations 
across the world and there is no guarantee of service or availability. 
The 
accuracy of digital compass headings can be affected by magnetic or other 
environmental interference, including interference caused by proximity to the 
magnets contained in the iPhone earbuds. The compass may need to be calibrated 
from time to time. When the device displays the calibration alert, move the 
device in a figure 8 motion until the calibration screen disappears. See http://support.apple.com/kb/TS2767 for more information.
N.B. This is not an AIS VHF Transponder. Your boat will not show up on 
other Ship based VHF AIS systems (unless they are linked to a common Global AIS 
system).'
Article courtesy sail-world.com, images courtesy Pocket Mariner and Google 
Go Pocket Mariners website on http://pocketmariner.com/boatbeacon/ for a full description of how to use Boat Beacon and particularly read the FAQ section.   
There are three apps currently available for Android and iPhones and are either free or just a few dollars for the more detailed ones.
We will look at these three models and their prices in our next post.
You can read much more about navigation and the cruising life in my ebook 'Sailing Adventures in Paradise' downloadable from my website http://www.sailboat2adventure.com