Updated 2012/03/31. All photographers need tools. Away from home, a hotel stay invites a big toolset; a car camp likewise. A large-volume sea kayak can carry the gear you need. With backpacking — or with minimalist-type sea kayaking — it's essentials only. Below is my typical backpacking camera gear list for the Canon 5D Mark III. You can go lighter with smaller frame cameras like the Canon Rebel series, a very tempting option paired with a 10-22mm zoom, but the low noise and high resolution of the 5D III has made it my camera of choice. Two thing of note: I've dropped the split ND filter(s), and instead take over and/or under exposures of identical scenes (on a tripod) to be combined later in photoshop. I've also added some kit to simplify panoramas.
I don't have a specific sea kayak camera list. Sea kayaks can carry a lot of gear, and my equipment changes to meet the needs of the trip.
Backpacking Camera Gear List
Tripod required: two separate images captured at the
scene and later combined in Photoshop. Canon 5D,
24mm f/3.5 TS-E @ f/11, 1/4 and 1/15 sec. ISO 50
Indian Henry's, Mt. Rainier NP
For three-season backpacking, I’ve chiseled my pack weight to 27 pounds for a 3-night trip: 13 pounds for pack, clothing, shelter, stove, etc.; 9 pounds for camera gear; 5 pounds for food. I wrote about light-weight backpacking photography in the 2009/10 tip, with an update in 2010/11 and 2012/01. Here’s my backpacking camera list for the Canon 5D Mark III.
| Equipment |    Weight |
|
  5.6 oz. 25.7 oz.   5.2 oz.   2.0 oz.   1.8 oz.   3.0 oz.    .4 oz.   6.9 oz. 41.9 oz.   13 oz.   2.4 oz.   2.9 oz.   1.5 oz.   4.0 oz.   1.2 oz.       9.28 lb. |
For trips of three days or less, I'm comfortable with a single battery, unless I plan to do star-trails. For a fast and light backpack trip, one lens is key, the versatile 24-105mm f/4L. For less vigorous trips or if I anticipate wildlife, I may go with two lenses— usually the 17-40mm f/4L and 70-200mm f/4L— and include a sock for padding and a 67mm polarizer. In sum this adds about 1.3 lb. for a total camera gear weight of 10.6 lb.
Gary
Also see FAQ for on-the-water advice.