Hi Konstantin, really good photos, thank you. The wooden parts are surprisingly well preserved.
Regards
Massimo
In addition to the surface treatment these aircraft received during construction, remember that the structure itself consisted of phenolic-impregnated wood laminate, which would resist decay much better than ordinary untreated wood. In general, a lot also depends on the type of wood and the oxygen content of the water. There are people who make a living recovering sunken logs and selling them to sawmills; even after many decades of submergence, these still yield valuable lumber after only a slight cut off the surface to clean them up. I'm surprised (and frustrated) when canoeing to see (and sometimes run into) submerged tree stumps and brush which I know have been under water for 100+ years, still showing very little sign of decay. Anyway, great photos and links - thank you, Massimo, 66misos, and KL!
John