The kaag illustrated in the centre foreground is sprit-rigged, which means that it has a four-sided fore-and-aft sail, the head of which is supported by a sprit that extends upwards from the front of the mast to the peak. A Dutch warship lies at anchor in the bay to the left of the picture. The man in the stern of the kaag is pulling on the sail. A kaag was a type of cargo vessel designed for use on inland waterways. In contrast to many river craft, it had a straight stem and sternpost, and a pronounced rake-a wide angle between keel and stem. It was often used as a ferry or a lighter in the Zuiderzee, conveying cargo to and from seagoing ships in the roadstead of Den Helder. The implied storm is emphasized by the height of the cloud above the kaag, whose sail has been highlighted in the foreground, as have the waves.