I've used the TK102B and GT-02A trackers in my cars and offroad vehicles. The TK102B has a battery
that will last a few days, and the GT-02A is a very slim waterproof model that doesn't have a battery
. They both use SIM cards and must transmit their location back to you via the cell system of the carrier that you select. I chose T-mobile because they have a $10 plan that's good for 3 months.
These units cost about $35 ea. and $3.33/mo. to track, they transmit a text msg to your cell phone
with a link to Google
maps. The drawback of course, is that your vessel may not be within range of a cell tower.
I've also installed battery powered GPS
trackers for Portvision, which uses satellites to communicate back to their servers and display the last known position based on the ping rate that you selected when you programmed the unit via PC software
. These were considerably more expensive, both to buy and operate. They have a web site where you can view your vessel tracks. Take a look at the Portvision website, they may have some cheaper options than when I last installed units for them.