No batteries required. Some are backlit though for night travel.
OS looks like the fish I catch you can just use for bait.  ;)

DB your navigation style is mine exactly. Or should I say usually. This trip I would like to employ a compass and follow a bearing. Learn a new skill where it's not crucial that I be without error. With my usual map reading and occasional GPS usage as a backup I want to get a "feel" for following a route by using a compass bearing.

I hadn't thought about it spinning as per the cheap clip ons I used to use. We'll see, this is a kayakers compass and other boaters use a compass so I suspect the dag-gone thing better work. (Or else my boys will meet with theirs.......sometimes things gets messy >:( )

It is removable but I have no intention of removing it and will take steps to insure that it doesn't want to find a new home without me. I will have a separate compass (probably a silva ranger) to keep on me. And of course a trail of gorp left behind to help me find my way back to the boat.