Recently I was in Alaska as part of an organized outdoor tour. Part of the tour involved sea kayaking. Sea kayaking is like regular kayaking except in... the sea (or ocean, if there is a difference).
We really didn't know what we were signing up for. We crossed a couple miles of very smooth sailing and a cold ocean and really were heads down, focusing on paddling (it was a double). When we returned from the round trip we were thankful that we were back on solid ground. When you are out there you get a brief taste of how big the sea is and the fact that you are in a tiny boat and it isn't a good feeling.
About ten years ago we were in Australia and spent some time in Tasmania. Tasmania is south of Australia and you can reach it by ship (ferry) or by plane. We went by plane after hearing tales of how wild the seas are down there.
I am watching a documentary about Andrew McAuley, an adventurer who went by sea kayak through the thunderous seas not from Australia (mainland) to Tasmania but from Australia to New Zealand. This is 1600 km (1000 miles) and he got to within 80km of his destination before his customized kayak with capsule turned over and he fell out and his body was never recovered.
Hat's off to that guy for having so much guts to take on that challenge... unfortunately he didn't make it and left a 2 year old son behind.
My tiny sea kayak experience is infintesimal compared to his efforts, just enough to give a tiny taste.