Giant shark encounter in Iceland

This was filmed in August 2022. We had seen lots of whales and dolphins during the day. Late in the evening we decided to go out on the boat. We skipped life-vests this time because we wouldn't go too far from the coast and the only life-vests available were large and bulky. But after rowing a little bit further into the fjord we noticed something floating not too far from us. We decided to go and investigate but suddenly we were further out from the coast than we had decided, and that's when this huge beast appeared. I just heard some additional sound of water moving and looked over my sister´s shoulder when I noticed this fin coming straight at us. At first I thought it might be an orca swimming sideways, but it never went up for air. I rowed to the left and the shark followed, I rowed to the right and the shark turned as well to the right. Then I took a U-turn back to the coast and the shark continued to follow. Then I decided to stop rowing and see if it would loose interest. At that point I was quite sure that it was a basking shark but still worried that it might collide with the small rowing boat that we were on. As soon as I stopped rowing it passed us and went down under the surface and we didn't see it again. It may look like we were much further away from shore than we actually were. The furthest distance to land was 400m but it is only visible at the very beginning of the video.