Golden Harbor is one of the 5 trading islands. Here you can buy Grain cheaply for sale at a profit at the Pirate Outpost (clockwise, to the left).
The Golden Harbor bank will loan you doubloons to use in trading or buying a larger ship. You pay 5% interest per trading day and must pay back the funds in order to get another loan. If you do not pay back your loan by the due date, you cannot buy a larger ship. Pay off the loan to restore your credit and you can make a larger loan.
(Generally, you should buy each larger class of ship as soon as you can afford it.)
To get the Treasure Map piece at Golden Harbor, you have to click on the street lamps (lanterns) so that the 1st, 2nd and 4th lanterns (counting from the left) remain on. The lanterns should be turned on from right to left : 4th, 2nd, 1st. The map piece will appear in the draped archway near the 3rd lantern.
go to the fisher man at the end and make him catch a fish then hit every light post and you get the map piece
there is five lights. click the lights in this order:4,2, and then1.
golden harbor
Skullduggery Island.
The archway is right to the right of the trading post in the golden harbor. You need to turn the lights on and off according to the combination.
golden harbor does
if you have all 5 map pieces, put them together and it will show you where skullduggery island is. go to skullduggeryisland and recover the buried treasure.
The bank on Skullduggery Island is the Golden Harbor Bank, located in the Arabic-themed port at the lower right on the island map.
Use your raft to sail to Golden Harbor.
There is a secret island on Skullduggery Island, and in fact that is its name : Skullduggery. It will appear on the treasure map (and actually in the open sea) when all five pieces of the map are assembled. It is near the bottom center, between the Pirate Outpost and Golden Harbor.
skullduggery island!
You repay the loan (in full only) at the same place you borrow it. The loan officer is upstairs in the Golden Harbor Bank at Golden Harbor.
The loan officer grants and collects loans. She is on the second floor of the Golden Harbor Bank at Golden Harbor (all the way to the right side).
The treasure is on Skullduggery Island, between Golden Harbor and Pirate's Outpost. You have to defeat Captain Crawfish and get the map that shows where exactly it is buried before you start digging. (Answered Provided by Little Bird)