Puerto Rico is a game about harvesting crops from your plantations and then shipping them. But the only way to ship anything is with the Captain role, and once the game starts there will always be jockeying for positions on the boats. Here are some tips about picking the Captain role:

• Generally speaking, you want to pick Captain as soon as possible after someone else picks craftsman. Once the game gets going, there will almost always be a fight for space on the ships, and picking captain can be the difference between getting three extra victory points, and having your barrels rot. Picking captain is important offensively to pick up extra points, but also defensively, to avoid letting someone else pick captain and force you to rot your extra crops.

• Picking up a warehouse can be a good investment that gives you a lot more flexibility with the captain phase. Once you can store a whole type of crop, you won't need to pick captain defensively because you won't be in danger of rotting your barrels. As an added bonus, having a supply of warehoused goods puts you in a prime position to captain again next round before craftsman happens, while everyone else only has a single barrel remaining.
• The harbor is another key building that augments your captain phase. The harbor is most effective if you can get on lots of ships, so producing four types of goods (even if it's just one barrel of each) can be very strong with the harbor. The harbor is so strong, in fact, it's often worth picking mayor to man the harbor instead of captain, if that won't lock you out of a ship. The bonus VP you lose from not picking captain will be more than made up for if you can get two bonus VP from your harbor.
• Consider your trade goods, especially in the early game. If you've just crafted a "cash crop" such as coffee or tobacco, you may not want to pick captain if it would force you to ship your goods for points rather than trading them for money. Early in the game, it's much more important to trade your cash crops for doubloons, so don't throw them on a ship. If you have multiple types of goods, captain may be a better option, because you can ship your cheaper goods and hold onto your cash crops.

• If you don't have cash crops, don't let your opponents trade them either. If the next player is sitting with an unprotected barrel of coffee that could be traded for five doubloons, picking captain might be the perfect way to deny him the extra money by forcing his coffee onto a ship for a single point, especially if you can ship a few cheap barrels in the process.
• As a general rule, it's important to look at what crops other players have available when considering the captain role. Ask yourself: How many types of crops are currently on the board? If the answer is more than three, someone's crops won't fit on a ship. If there are only five spaces left on the corn ship, and nine corn on the board, someone's corn won't fit on the ship. Don't bother picking captain when there's plenty of space for everyone, but be quick to grab it when shipping room is scarce.
• Finally, when placing goods on a ship, pay attention to what options other players will have. If your opponents all have a lot of corn, you may wish to place your corn first, to assure that yours ships and theirs can't fit. Conversely, you may wish to start by placing a crop on which you have a monopoly, to tie up the ship for your personal use. When placing crops on a ship, you should always be thinking not only of how many points you get for that placement, but what will happen with the rest of the ships this round.