wave riding, shark

one always hears about sharks or seeing a picture or video and felt nothing to it. But when you actually see a fin swirling around your aft/stern cabin), you may stop breathing for a second. I did today. I was on deck rowing/the North Atlantic towards England when I spotted a shark following on my aft/stern cabin. I called Ran out of his cabin in case it attacks under. It followed us for 10 minutes and disappeared. Probably the shark was curious. I did not need any motivation to row away faster.