Yes, sailing is much more challenging than one might think. I used to live a very adventurous life. Been in some really hairy situations. But, one day, me (14 at the time) and 2 friends, took a 45 foot sailboat we “borrowed,” from the yacht club and took it out the golden gate. We all had a lot of experience sailing. As we went under the golden gate, the ocean became absolutely diabolical. It went from a sunny, lightly windy day, to winds gusting to 75 mph and 25 foot waves, and a wall of fog so thick, visibility was maybe 10 or 15 feet. My friend, who was going to Olympic trials for sailing, had a look on his face that indicated we were in mortal danger. The next few hours were spent fighting for our lives existing solely on adrenaline at that point. We were soaked and frozen, pure misery. The ocean is very cold in Northern California. If we were novices, we would have 100% died. If you are taking to the ocean, you better know EXACTLY what you are doing. You NEVER know what the ocean will do. Even if you have a yacht with a decent engine, you need to know the ocean. Things can turn in a second out there.
I suppose you could be a shore cruiser. Always stay super close to shore so if you have to abandon ship you might be able to swim in. As far as crossing an ocean, the greatest heights of madness.
One time I got wasted in France, met a girl, went down to the docks and hooked up in a row boat. She took the oars out to make room. Well, we passed out, and when I woke the next morning, we had drifted so far out I could barely see land. This was a slightly alarming development that turned into two days of dehydration and pure hell. Beware of large bodies of water.