We have owned a SPOT for somewhat more than a year. I originally purchased it last year for my daughter who, with 9 other teens, was sailing a Beneteau 50 from St. Martin to Trinadad over the course of a month--from early June to July. We subsequently used it for an extended cruise to the Keys on our own yacht.
The "I'm okay" function sends out 3 I'm Okay messenges at 10 minute intervals to ensure that at least one will be delivered to designated email addresses specified by the user.
The "Send Help" button sends ones position every 5 minutes for an hour until the message is deliver to specified email addresses or the alert is cancelled.
The "9-1-1" alert is sent every 5 minutes until the message is cancelled or power is depleted. With the "9-1-1" message, the Rescue Coordiantion Center closest to the position encoded in the message is notified.
If one signs up for the rescue service provided by Geos--a division of Blackwater that provides private security and rescue services to private contractors, the State Department employees, et al--Geos will arrange rescue with the RCC and, if necessary, mobilize private resources to effect a rescue and evacuation (see GEOS Search and Rescue (SPOT)
). This, of course, involves an extra charge.
In the "Tracking mode", a tracking message is sent every 10 minutes for 24 hours. With this, the users position is plotted on a Google Map that can be accessed via the web by anyone with the shared web address. (The following is a track of our afternoon sail this past Monday SPOT Shared Page
Following our daughter's trip, we loaned our SPOT to some friends that were bringing their Island Packet 38 from Nevis to the Tampa Bay area and we were able to follow their track for 10 days. When they arrived in the Tampa Bay area, I was able to follow their track from our boat well enough that I walked out to the breakwater to watch them as they sailed passed our yacht club at 10:00 PM two daze before Thanksgiving and was able to drive down to Twin Dolphins Marina to greet them as they arrived there (and split a nice bottle of wine!).
With the correct batteries, the SPOT operates for two weeks or better, 24/7.
There is a lot to recommend the SPOT as an adjunct to an GPIRB but it is not a substitute for one, and its cost for yearly service subscriptions, is substantially more than the cost of an GPIRB or PLB over the battery lives of those units.