Wood seasoning and the economics of fleet replacement

Seasoned timber might give a wooden ship twenty to thirty years of service, depending on use, while an unseasoned hull might last roughly a decade. The suggestion that most Song ships used unseasoned wood is an inference from their descriptions. It could make sense for riverine craft that suffered frequent collisions and needed replacement within ten to fifteen years. Building those hulls to last much longer would offer little benefit if damage forced their replacement anyway. Smaller ocean-going ships might also follow the same construction methods where yards were already producing large numbers. Seasoned timber seems more plausible for large seagoing vessels, although that expectation does not establish how particular Song ships were built.