First, make sure you have some Langridge (or other Anti-Personnel Shot) and some Bar Shot (or other Dismantling Shot) as well to slow down your prey before taking out her crew. Keep in mind, when you purchase any type of shot from other players or the AH you are purchasing crate/s of shot. After you purchase the crate/s, it goes into your ship hold or your warehouse. Now, you must right click the crate/s, then left click on "unpack the crates". You now have actual units of shot in your ship hold. Now, drag and drop the Langridge icon from your cargo hold window to your hotbar so you can "load" it when you are in combat.

[edit] Boarding UI

Everyone starts with the boarding skill, you DO NOT need to earn it. Keep in mind, you will only be able to board when you are within 50 yards of your Target. At that point, the Grappling Hook button will appear below the ship UI. If you hover the cursor over the Hook you will see a percentage chance to Board the Target, and you can simply click (I found that it does not always work on the first click so be ready to click a couple times) on the Hook to attempt boarding. I the skill icon should also be available to use on your hotbar unless you've removed it. It looks like a pirate swinging on a rope. If it's not there, you can drag it from your Skills window to your hotbar as a backup.

[edit] The battle begins!

Check whether your intended boarding target brings friends. As a word to the wise disable or sink his friends first unless you intend to board them too. This is essential in many missions to avoid being shot up while you board your intended target as enemy ships in most missions keep firing on your ship while you are in boarding combat. When you start a battle and you plan to board the enemy straight away, load your Dismantling Shot either Chain Shot,Star Shot or Bar Shot before you get into range so that it will be loaded and ready to fire. I recommend Star because it does the most damage, but it has the shortest range also. In fact this type of shot has a much shorter range than Heavy Round Shot, about half. When you are in range fire your Dismantling Shot to slow down your prey so they will be easier to board. It may take 4 or more shots to get their Sails/Masts down to 50% or less. By now you can load your Grapeshot or Canister Shot. As you position for the boarding fire 1-2 broadsides with the Anti-Personnel Shot. This should cut their crew by about 50-90% (for smaller ships). Keep in mind that you are only injuring most of their crew and they will regain health and crew quickly, so be prepared to fire more Anti-Personnel Shot as needed.

[edit] Finally, time to Board!

Now, try to maneuver your ship into position (slightly ahead and along side your enemy) without taking too many broadsides from her in the process. Ideally, you want to cut them off stopping with your broadside facing their bow. Once you close to within 50 yards you will see the Grappling Hook icon light up. Your objective is to be going the same relative speed as your target - if either you or your target goes faster than 8 knots boarding is impossible. The slower the better, STOPPED IS IDEAL.. The slower you are each going, the higher the chance of boarding. In normal circumstances, you have 100% chance of boarding if both ships are not moving. There are however some skills and ship outfittings that can increase or decrease the percentage. There are also penalties relating to ship size (eg a small ship trying to grapple a huge ship has a penalty to the chance to grapple). The Grappling icon should change colors depending on how high your chances are for success and if you hover your cursor over the icon a percentage will be displayed. Now is the time to use your grappling & boarding skills if you are high enough level to acquire them. Wait until you can get the UI green about 65% or more before clicking the Grappling Hook . You will go into a separate boarding instance.

[edit] The Boarding Action!

The aim of boarding the enemy ship is to kill the enemy captain and/or crew. When the battle starts (after a short period while the countdown timer on screen runs down), the two crews will run towards each other and start fighting. Your best bet is to stay behind your crew when they run in. A wild melee will start, and you want to use your captain to the best effect, and hopefully take down the enemy captain as quickly as possible. At this point, I'll explain the mechanics of the boarding action as I understand them, and then suggest the tactics you can use to maximize your chances of winning.

Your crew will at one end of the ship, the enemy crew will be at the other. The amount of crew you and your enemy have is based on the size of the ship being boarded. Smaller ships will have 4 crew plus the captain on deck, and in each wave of reinforcements. Larger ships will have 5 in each wave. The number of waves of reinforcements for each side is determined by the relative size of the crews each had in the ship battle at the moment of boarding. Note that the number of crew in a wave is the same for both sides, at least until casualties start occuring. It is only the number of waves of reinforcement you have that varies.

Now for a key mechanic - a reinforcement wave gets used up whenever a captain (you or the enemy) respawns, or when either side calls for a new wave of reinforcements. When a wave of reinforcements is called up, a number of new crew appear to replace the fallen, but only enough to bring your total crew on the deck up to the original number.

Boarding Tip #1 - Target the enemy captain - the captain will be tougher than any one crew member, but killing him is easier than killing the rest of his crew, and has the same effect - it uses up a reinforcement wave to replace him, or them. The best way to take out the captain is to select him (or her), and then issue the order to your crew to concentrate on him/her. If you have the pistol skills, save your shot for the captain, don't waste it on a crewman. Assist your crew and attack the captain, but pay attention to Tip #2.

Boarding Tip #2 - Protect your own life - especially if you have less waves of reinforcements than the enemy. Everything I said above applies in the other direction to you. You are (or should be) smarter than the AI, so act like it. Take risks only when it is to your advantage. You have skills that can manage your crew to some degree. If you have taken a lot of damage, use your crew to block the enemy or hold the line so you can get far enough away from the enemy to be able to use first aid on yourself.

Once you have taken the enemy captain down, if there are no reinforcement waves left for the enemy (you can check on the Reinforcement Waves window on the top right of the screen), you have won the boarding battle. If there are one or more reinforcement waves for the enemy side, the captain will just respawn in 10 seconds. Similarly, if you die in a boarding battle, and you still have reinforcement waves you will respawn in 10 seconds on your side of the ship, otherwise you lose.

When the enemy runs out of crew, if there are reinforcement waves left, the enemy captain will call for his next wave of reinforcements, which will appear on the raised deck at the enemiy's end of the ship. Similarly, you should call for a reinforcement wave when your crew is reduced Your crew does not respawn until you call for reinforcements. If you are left alone on the deck, you will be swarmed by every surviving enemy crew, and will likely die very quickly. Also, when your crew respawns they will appear back at your end of the deck and it will take some time for them to rush to your defense, so allow for this, especially if you are fighting well down at the enemy end.

Boarding Tip #3 - Time your reinforcements carefully! If you call them too soon, you are only getting a few men as reinforcements instead of a full wave. But, if you wait to long, you risk being swarmed and taken out, which is even worse.

One thing to consider is the layout of the deck. You won't have much time to look at it, especially if you experience much lag - once the countdown timer runs out, the fight will be hectic. There are obstacles on the deck, and thse create choke points that can be problematic. Each crew starts on either the raised poop or bow of the ship. There will be two stairways leading down to the main deck. If you manage your crew well, you can keep the choke points blocked fairly well, keeping your captain safer. This is especially true for the two stair cases at each end of the ship. If you manage the fight rather than just chopping away at everyone in reach, you are more likely to win the fight.

[edit] After the Boarding Action

If you win the boarding action, you will return to the ship battle. You will have loot to claim, and the enemy ship will be a derelict (which navy, freetraders, and privateers can claim as commendations or pennants, and which can be scavenged or taken command of by pirates.

If you lose the battle, you will go back to the ship battle, next to the enemy ship, and you will not be able to re-board for 30 seconds. Depending on the relative sizes of your remaining crew, you may try to reboard. Keep blasting in the antipersonnel shot to reduce the enemy crew, and you can also use Rum or various other consumables to replenish your crew before boarding again.

In either case, if there were other ships (enemy of friendly) about, besides the one you boarded, they will have continued to maneouver and fight while you were busy with the boarding action. Check your ships status, and if necessary use your skills or consumables to repair any damage (including crew loss) that is a concern. If you are in danger, do not waste time looting the enemy ship, but instead, do repairs, raise your sail and get back to fighting. You can come back for the looting and scavenging later. That's one of the advantages of winning a boarding fight - the enemy ship will likely be in better shape, so unlike a ship that was abandonned after being shot to pieces, it is not likely to sink anytime soon. You can also raise sails and still pick up loot items once you're moving, as long as you haven't gone too far before clicking on the loot box. I beleive that to scavenge or take command of a derelict, you have to be moving fairly slowly and be within 50 yards or so of the derelict, much the same as when you are trying to board.