Rain shaft seen at sea

A rain shaft is one type of precipitation shaft; other types are hail or snow shafts. They appear as dark vertical shafts emanating from the clouds. We recently saw one such rain shaft at around 9 pm on our overnight ferry trip back to Oslo from Copenhagen. This shaft was not very wide but was a bit fuzzy. Although it was not raining at our location, it was clearly raining in a very localized spot over land to the left of the ferry (northeast Denmark). A strange weather phenomenon! I managed to get a few photos of it. The other interesting thing was that the clouds in the sky all seemed to level out at the same lower position, something I've never seen before. The natural world never ceases to amaze me.