Coastal defence ships were particularly popular in the Nordic countries, and began serving in the navies of Denmark, Sweden and Norway early in the 20th century. These vessels typically had heavy armament and good armor protection, but were relatively slow. Their sizes were around 4,000 tons, main armament consisted of guns between , the armor corresponded to that of armoured cruisers, and speeds were between . A coastal defence ship was somewhere between a cruiser and a monitor: slower than a cruiser but better armed, faster than a monitor, but with smaller guns. The coastal defence ships also varied among themselves; some of them were closer to cruisers, and others, such as the Finnish ones, were closer to monitors.