yup, GMRS.
if you're going to invest in GMRS, get a base station with a repeater function to make your range reasonable.
example, Midland - MXT400 is a 40W - add a decent antenna at a good height and that should be nice for short range patrols. i picked it a bit at random - its semi portable - think gator or quad.
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i still like the idea of using a set of maritime radios in a TEOTWAWKI. - cheap, good range, and an odd band when used inland.