(
Approx $40
Even in this age of low-cost GPS, a compass is an essential tool... don't let anybody tell you otherwise! First, when the GPS tells you where you are and gives a range and bearing to your destination, it doesn't mention which way that happens to be if you're not already moving (and yes, some units, like my delightful Garmin GPSmap-76S, have a built-in flux-gate compass... but that turns out to be too fiddly on a kayak, as it insists on being absolutely level). Second, you need actual heading data in addition to knowing the direction your boat is pointing to deduce the set and drift of currents without getting out a chartboard and running a dead-recknoning plot, impractical while paddling. And finally, when your AA batteries die in the middle of a crossing in the fog, you really come to appreciate the reliability of a deck compass to keep you moving in more or less the right direction!
You actually need two compasses for kayak coastal navigation: one mounted on the deck and a hand-bearing unit stashed nearby for taking sights without having to stop and re-orient your boat. This one is the former... and it's a good, small, fast-settling unit that's well-suited to feisty little vessels. I use an almost identical model (different housing, same capsule) on the console of the Microship, with a red LED retrofit to make it visible at night.
The compass itself can be snapped out of the yellow housing and carried separately during transport, if you're worried about security. I recommend this unit over the competing models that require 4-5" of deck space.
There is a huge difference between nautical charts and road atlases, of course, and naturally the former is your first choice for navigation on the water. On the scale of coastal kayaking, however, it turns out that a variety of cartographic tools are useful. I normally carry four on any given trip: the waterproof SeaTrails map
On a kayak, this translates into useful coverage of rivers for which there are no charts, data about nearby shore features, and a satisfying "big picture" scale: each page of the Washington atlas, for example, covers 23.4 x 34.5 miles (this will vary with latitude). They certainly don't tell you all you need for open-water navigation, but they do offer one huge plus: uniform coverage of the whole US, not just coastal and offshore features. This makes them a perfect place to log your kayak trips (like this).
For other states besides Washington, just click the Amazon link at left and then explore from the "You may also be interested in these items..." area. There is also a complete selection of all the DeLorme Atlases