This requires a character with positive reputation and medium to high commerce level.

Go to the first tavern you find and hire an officer. When the dialogue text comes up choose Isn't that to much? Keep selecting this choice until the amount you will spend for the officer is a negative number.

Repeat this process until you have the desired amount. You can lower this amount by a max of 1000 at a time with a commerce of 10. (Each point of commerce equals 100 gold).
If you run into a pack of unsavory characters, and don't think you can best them in battle, flee from them and go past the last point where the game loads. They will not follow.

Enter the following codes on land or in ship command mode:

A, X, Y, B, Y, B, X, B, B, A - Accrue 100,000 gold
A, Y, X, X, Y, Y, B, Y, X, A - God mode for self and your ship. Sails and ship crew unaffected.
A, B, Y, X, Y, B, B, Y, B, A - Accrue 50 Skill Points
A, X, Y, X, Y, B, B, Y, B, A - Set reputation to neutral

If you get yourself into a bad position in a sea battle, and know you're going to be blasted with serious cannon fire, there is a way to avoid it. When you see the smoke from the guns, quickly Sail To a different part of the ship and you should completely avoid the blast.