Easy money
Go to any of the loan sharks and ask for any amount of money. You can go to the box in his office and drop your money in it. Then, go up to him again and ask for more money. Continue to do this until you have the desired amount. Even though he says that he has ways of getting his money back, he never comes after you.
Stack captain scores
You can add more than one person, other than the Captain, onto your other three ships. All of their scores will stack with that ship's captain's score. There are two different ways to do this. The first method is at the "Open Sea" screen (where you can see all of your ships), get close to another one of your ships and a swap cargo icon will appear. Go into the swap cargo menu. There is an option to switch captains. Under this option, there is a screen that has four slots. One of them is the captain of that ship. Click on one of the other three slots, then assign passengers to each one. When you do this, they dissapear from your passenger list. You will need to get more party members at the tavern if you want to fill up all your ships. Do not sell the ship with the other three crewmembers still on it. You will lose anyone that is still on board. The second method is to capture a ship and do it when you assign a captain to the captured ship.
Unlimited Money
Raise your Commerce to 10 as soon as you can (use all the points you get towards it). Then, go to a tavern and talk to an officer that you can hire and ask him 'How much are you asking?'. He will respond with a price. Then, say 'Isn't that a little too much for you?'. He will reply 'I guess you are right' and then offers less. Say 'Nah, still too much' ( or something to that effect) and the dialog box will close. However, the next time you talk to him, the price will be the last price he offered. Repeat this until he responds with a negative number (i.e. he will pay you for you to hire him).
Ding Dong Ditch...