Last month, I spent a weekend in a small fishing village in Maine. I chatted with a retired boat builder about preserving wood against salt air. He showed me his mix of linseed oil and pine tar. Now I use it on all my outdoor projects. The durability is unmatched, even in harsh weather.
He was trying to impress a client and gouged the oak pretty badly... Watching him recover with a random orbital sander changed my entire view on when to use modern tools.