What coins do I have in my hold at the beginning of the game?
Is it possible to have any spare coins in my hold or has the hold to be empty at the beginning of the game.
I was just wondering cause the rules state that it is possible to draw a second captain through buried treasure.
Where does this spare captain come from?
It had to be in the hold right from the start, right?
Does that mean, that shipyard and hold can be the same thing at once?
I´m kind of confused. 
Your hold is always empty at the beginning of a game. Any coins leftover in your shipyard (above the 13 that make up your ship in the current game) are not part of play at all in the current game.
That rule about drawing a second Captain using Buried Treasure is there to address the (unusual) case where you're playing a multi-player game, lose your Captain (so it's in your hold), then Pillage a Captain from someone else, and then use Buried Treasure. If you happened to draw your original Captain from your hold at that point, you'd be in violation of the two-Captain rule. So this clarification solves that problem.
Does that answer your question?
Yes, this perfectly answers my question.
THX!