I have a full out battle strategy.
A. When the invasion is announced, get a few, outspoken (not too much though) pirates who can inspire, and work as leaders.
B. Use these to gather together as many recruits as you can.
C. During this time, gather as many of your guild and crew as you can.
D. Gather a group around you that will listen to you, and will follow orders. (hard for pirates i know)
E. First, split these loyal allies into regiments ( about one-third should go in each ), and further break them down into companies. ( You should appoint a leader for each regiment, and then another one for each company. The company leaders will answer directly to the regiment leader. )
F. Make sure they are in fairly orderly lines. And make sure they don't run away. ( Try a few, FOR THE CARRIBEAN!s ) Get guns and grenades towards the back ( healers may be in the midst of the frenzy, but a few should be behind the grenadiers. ), staffs in the middle, and Cutlasses/daggers towards the front.
A few tips
If your barricade falls, pull back a little. (Not always neccessary)
Make sure the Mansion has a
fairly well supplied force.( I say fairly because hopefully Jolly Roger won't ever make it there.)
Lastly, Keep your forces together and fairly orderly. If you don't hold together, they may retreat, and be picked off
one by one.
Here's a map of the invasion. The blue circled areas are places where there should be a high concentration of pirates, the bright red is the path the undead seem to take, orange are barricades, and the red dotted line along the right side is the path Jolly himself will take.
http://www.piratesonlineforums.com/g.../Screaming.jpg