on the cell phone thing, just remember to turn off all the non-essential apps and you'll save a lot of battery life.

I can do it in "settings / Application manager", but i don't know how you do it in Apple phones.

E-mail, messaging, app store, music service, etc. all run in the background and probably sap your battery life. "Close all" and then just open Kattack.

Normally, I'd switch to "Airplane Mode" as well, but I suspect you need the cell transmission to continuously track the boats, right?

I go in airplane mode when I'm using the Navionics app since it uses the GPS (which still works), and won't kill the battery looking for a cell signal when I'm more than 2-3 miles offshore...