Cabin Fever

War o' words
Travel to Port Phasmatys - bring ecto-tokens, and the Ghostspeak amulet if you have not completed Ghosts Ahoy, or you may also charter a ship for 3,500 coins (requiring no ecto-tokens, 2 ecto-tokens still required to speak to Bill) and speak to Bill Teach in The Green Ghost Inn. Bill is the captain of The Adventurous, a ship which he claims is the finest ever to sail the seas. He needs a pirate to help him leave the port, but none will sail with him, not even his crew.

Last night, he had a heated argument with the captain of another ship, wherein the captain threatened to sink The Adventurous and put his crew "to the sword". Scared, all his crewmembers have abandoned him and he has no choice but to sail back to his home land.

Seeing his dilemma and wanting to be a pirate, you offer to help him. Although he doubts your plundering abilities, Bill accepts your help and tells you to meet him on his ship. Go to the Port Phasmatys docks, and board the easternmost ship, The Adventurous. Speak with Bill to set sail for Mos Le'Harmless and begin your journey as a pirate.

Under attack!
As soon as you leave port, you see a cutscene, where an enemy pirate ship starts firing on The Adventurous, destroying the ship's hull and cannons. Bill calms you down and tells you to first take care of the enemy's cannon.

He suggests you grab some fuse and rope from the ship's bottom deck. Climb down to the bottom deck and search the repair locker, to take out six ropes. Search the gun locker located near the repair locker, and pick up a fuse. In the southern corner, there is also a tinderbox; grab it. Climb up the ship's ladder to the main deck, and use the climbing net to climb up the main mast. Use your rope on the hoisted sail of The Adventurous to swing over to the enemy ship. If you fail the jump, your run energy will drop considerably.

The ship is populated by level 57 pirates. If you need to escape from them for a moment, climb up the net on the main mast. For your job, find the powder barrel next to the cannon on the west side of the deck and use the fuse on the powder barrel. Light the fuse to blow up the barrel and the cannon. Climb back on the main mast using the net, and using a rope, swing back over to The Adventurous - if you forgot to bring a second rope, you can find one in the southwestern corner of the main deck of the enemy pirate's ship.

Shielding
Now that you've controlled the offence, you need to build your defence. Talk to Bill, and he'll want you to repair the damaged hull. Climb down the ship's ladder and search the repair locker for: Each of the three holes takes two planks, ten tacks and one swamp paste to fix. When you have enough resources, a message in the chat interface will say so, if you try to get more than is needed.
 * 6 Repair planks
 * 30 Tacks
 * 3 Swamp paste
 * A hammer

For each hole, use a repair plank and then a swamp paste on the ship hull to patch it up.

Then, go talk to Bill again.

Retaliation!
For attacking your ship, the enemy pirates need to be taught a lesson. Bill asks you to pillage the enemy ship and bring back their booty. Climb down the ship's ladder, search the repair locker and take two more ropes (if you didn't take 6 originally). Return to the main deck, climb the net again, use a rope on the hoisted sail, and swing back over to the enemy ship.

Climb down the ship's ladder. Steal from the chest, loot the crate and ransack the barrel for enemy plunder; you will need to wait for it to respawn. You need 10 plunder, but looting all three once only provides you with 6 plunder, 3 being from the chest, 2 from the crate and 1 from the barrel. It can take anywhere up to 5 minutes for the plunder to respawn; however, you can simply log out and log back in for the plunder to respawn. The barrel will respawn fastest, then the crates and finally, the chest.

After you have ten plunder in your inventory, return to the main deck, and return to The Adventurous.

Climb down the ship's ladder, and use your plunder on the plunder storage at the back. If you leave the ship, you will lose the plunder and have to steal it back over again. Also, you can only store ten plunder; Bill will confiscate any surplus in your inventory when you talk to him.

Into Davy Jones' Locker
Finally, Bill wants you to prepare a send-off for the enemy. He wants to give the enemy pirates a blast, from the cannon. The aim here is to prepare the cannon (follow steps below) and to fire the cannon when the pirates are in front of the cannon on the pirate ship, so that you will hit them. Follow these steps to repair and fire the cannon:

Climb down the ship's ladder, search the gun locker, and take a cannon barrel. Trying to take anything else at this point will result in the message "You do not need a [item name] right now." Climb back up and left-click the broken cannon to fix it (The cannon will have the option "Repair broken cannon").

Talk to Bill again, then go below and search the gun locker for a ramrod, a few fuses and a cannon canister. Return to the main deck, and choose the take-powder option from the powder barrel next to the cannon.

Gunpowder can be obtained from the powder barrel located right next to the cannon, just left click the 'take powder' option.
 * 1) Use gunpowder on the cannon.
 * 2) Use the ramrod on the cannon.
 * 3) Use a canister on the cannon.
 * 4) Use a fuse on the cannon.
 * 5) Fire the cannon!
 * 6) Use the ramrod on the cannon again to clean it out.

If you miss, use the ramrod on the cannon to clean it out and then repeat the steps, until you score a hit. If you don't clean the cannon, it will explode from the previous unused gunpowder. If this happens, replace the broken barrel with a new one from the gun locker.

When you hit the pirates with the canisters, talk to Bill. He tells you to sink the enemy pirate ship by blasting holes in its hull; three would be enough. Go down below, and search the gun locker to take three cannon balls. Up on the main deck, clean the cannon out with a ramrod and then repeat the steps - except for loading the cannon with a cannonball this time, and not a canister - until you have hit the enemy ship three times.

Mos Le'Harmless
Following your third hit of the enemy pirate ship, you see a cutscene with Bill Teach talking with Mama Le'Fiette in The Other Inn. Bill then thanks you and gives you a Book o' piracy, to add "pirate" to your vocabulary as your ineptitude at speaking "pirate" annoyed him to no end in the voyage.

Reward

 * Quest points
 * Crafting experience
 * Smithing experience
 * Agility experience
 * 10,000 Coins (only if you speak to Bill Teach after the quest)
 * Access to Mos Le'Harmless
 * Access to kill cave horrors
 * The Book o' piracy
 * Charter ship prices are halved

Trivia

 * During the Ranged level check for the quest, Bill Teach asks the player about shooting an albatross. This is a reference to poem  (1798) where the ghost of a sailor tells a tale of killing an albatross with a cross bow while out at sea, leading to the death of his crew and himself.