Yet of the COG remains its MOSS - polytrichum commune - flourishing all over the region.
Since Soviet studies had to ignore dendochronology (tree-ring dating) & Chernobyl’s radiation (=false chemical dating) & skirt the limits of KGB monitoring,& since 1992 each free
Baltic country is just now recovering both hidden histories (Countess von Przeździecki’s Latvian Terra Mariana from the Vatican) & secretly-kept skills (primitive cogs spotted on each side of the Estonian/Russian water border) meanwhile MOSS became a Baltic celebrity!
Botanists reported keenly on this moss' water-proofing characteristics in flooded villages - vital knowledge from medieval cogs built/fixed on Baltic sorties, using scavenged or scrap wood to stuff 40-80cm lengths of this easily-found, water-directing moss into any gaps
btw clinkered strakes (overlapping side-pieces) where scarfed (joined to make one long strake). And this MOSS is the best indicator of hydrogeologic instability (land becoming waterlogged) - useful knowledge for medieval people on the move & archaeologists seeking them.
In 2010 I used the "De itinere navali" chronicle to identify cogs from the western Baltic using the moss Polytrichum commune, of which 7 types still grow in the Riga-Tartu-Jerzika bioscape where a Slav chief was caught between Catholic & Orthodox raiding groups in 1210.