Yes, the wave sounds are a bit strange. They sound more like a someone sitting in a bath doing repeated rhythmic movements and click sounds, as the loop is clearly to be heard. This also applies to other vessels. But this definitely doesn't sound like a ship moving ploughing through the waves, which you nearly don't hear inside the ship on bigger vessels - standing outside, it is a very different sound.
It is my impression, that the sounds - teh engine and horn sounds as well - were not ready when the game was released. But we can always hope that the Creator's Forum will create new sounds as they did for SS08 - thanks again - these horns are great!