I think this is the first time I have heard of Chestnut wood being used for a dock.
Here is very common to use chestnut wood for external and long-lasting uses as containment of slopes, reinforcements for the banks of channels etc.
I never even heard of someone who used it to make a dock here too, but I wanted to try and for now I'm very happy of it.
It is still stable and perfect as the first day, so only time will tell if it will be a successful experiment or not.