Caulking the ships on the IJ at Amsterdam by Reinier Nooms, mid 17th century. Wooden sailing ships needed constant maintenance. They had to be examined after every voyage. To close gaps in the ship's outer planking with pitch and old rope(caulking), the vessel was careened on to its side bringing the hull out of water. Big ships only came into the harbour if they were due for repairs or to be laid up. Otherwise, they would remain out in the open water: in front of the line of posts (left) that protected the city and harbour from the IJ. The cargo was transported to and from the quay in smaller boats.