Question about Gold

Hey guys whats up im new to these forums as of today. Ive been playing the demo alot since it came out. Now i have used the mega city strats that i have found on these forums. I maxed out my population at 31 and could only produce 1014 GPT. I built the Trade fair, market and the bank. I have noticed in some Screen Shots that you can get 3 gold on 1 sea square what do you need to get that.

Does the city have a Great Explorer (+50% gold) and are you using Democracy (+50% trade)?

East India Company wonder has +1 trade in sea squares.

PS: Welcome to the forums, Steveox15.

I did have democracy but not great explorer and this site helped me figure out how to get the east india trading company so thanks alot for the quick response and awesome site guys.