About the War Flag
With some help of the Maritime Museum in Stockholm and the Naval Museum in Karlskrona, I've made some research about the size of Swedish naval ensigns.
The size of Swedish ensigns
The size of ensigns used by the navy are not given metric by length. Instead the width is given in "dukar" (plural of duk, flaggduk=bunting). This goes back to old military regulations, at least mid-nineteenth century, where it was stipulated that the wool bunting "shall be of domestic authorized manufacturing, 18 inches [45 cm] wide, evenly woven and well edged, without loose threads across the bunting, that shows that the weft is thinner than the warp, which can not be considered as good, the weft and the warp must be equally thin." Reglemente den 20 maj 1847.
So, a flag measuring 180 by 90 cm is designated a "tvådukare" (two-cloth or -bunting), a 360 by 180 cm a "fyrdukare" (four-cloth or -bunting) and so on. You can see this on the heading of an ensign. Under the three crowns of Sweden, for example 2 D or 4 D is stamped.
Stefan Klein, 1 February 2002