What is the price of power and water supply for the yachts?

The water and power is from machines which are not automatic sellers.
For water the price is 3€ per 200 lires and for power 3 € per KW.
Vat is not included in the given prices.

Where can I pay for the port taxes?

At the cashier of the Port Fund (Laiki Kyriarchia sq,) to the person responsible for Syros port.

Where can I pay the fines of Coastal Guard?

At the cashier of the Port Fund or in the following bank account of Piraeus Bank:
Account No.: 5710-017689-636
IBAN: GR52.0172.7100.0057.1001.7689.636

Where can I object for a fine I was given by the Coastal Guard?

At the Port Authority of Syros in Laiki Kyriarchia sq.