1.Gather a full crew. Make sure they stay about lvl 25 and up. Try to get a man who has take cover. It is best to have a crew of 12 (including you).
2.Entering the Black Pearl. You could skip or watch the cutscene. When you are on the actual Black Pearl, you will have to face officers (lvl 28 and up). It is best for someone to use their staff if they have one.
3.After the officers, have your "take cover man" take the wheel. Then, Light Frigates will appear. Don't waste your best ammunition but at the same time kill'em quick.
4.Allow your steering man to go. He should allow enough space to shoot the towers guarding the drawbridges. Once you did that go as fast as possible and shoot the last drawbridges AS QUICKLY AS POSSIBLE! ALMOST EVERY ATTEMPT LOSE AT THIS PART!
5.If you actually made it here then your in luck. After the drawbridges, have everyone head to the LEFT CANNONS. THE GOLIATH WILL APPEAR ON THE LEFT. Then shoot him with ALL YOU HAVE! Try to hit him long enough so that your steering man can drive away fast. When you escape.........
If you had to do it for the quest at the end, head back to Jack Sparrow in Faithful Bride in Tortuga. He will give you 2000 Notoriety points, and you get the special sailing skill Leadership (i have it :))
Hope this helps! Happy PLunderin!