Sea kayaking differs quite a bit from whitewater kayaking. The kayaks one uses on the sea are quite different both in shape and in size from the whitewater kayaks. Whereas the whitewater kayaks are small (about 6-8ft in length), sea kayaks are usually between (12-17ft.) Whitewater kayaks are all about maneuverability, you can spin them 360 degrees with 1 or two strokes almost within a few seconds whereas with sea kayaks it takes quite a bit of effort. Sea kayaks on the other hand are made for comfort and speed. Whitewater kayaks on the other hand are quite painful to paddle in flat water as they are not built for speed.
Anyways, coming back to the original topic, the book goes through a lot of real life stories about how people got in trouble while kayaking in the sea. Some of the mistakes committed by the people were simply due to a lack of understanding, preparation and practice. People have gone kayaking in the sea without putting on a lifevest or keeping the lifevest under their seats. In one unfortunate case, the body of the kayaker was found drifting. When they recovered his kayak, they found the lifevest still tucked under his kayak seat!! There were cases where people were caught unawares by the weather. Even experts got caught up in unfamiliar situations and barely survived because they had flares, wet suits and other survival gear along with them.
It amazes me to no end how people take such risks with no regard to their own lives or the repurcussions on the lives of their well wishers. I remember the story of two Indian men, who were found hanging to the side of their rental kayak in one of the bays around Seattle. Neither were strong swimmers, they went out without any additional company in a double seater kayak. They had no warm clothing on and had no self rescue training. Their kayak capsized and they could not get in. When the boat found them, both the guys were hypothermic. One of them did not survive the ordeal.
I know of friends who go kayaking in the lakes around Seattle without even knowing how to swim. The waters of these lakes is cold year around and it takes 15-20 minutes for hypothermia to start setting in, any time of the year. Assuming a capsize, it would take at least 10-15 minutes before help would arrive and what if it doesn't?