I like the half plunder costs suggested by Haron. I would say 2 turns plunder, 1 turn skirmish.
Alternatively....
HNs and FFJs have 100% piercing for the day.

Most Lee Harmless wrote:Pirate auto-win : every hit is a win with 500% increase in plunder gained and all the targets ships are sunk and it only costs one turn to raise them!
Did I mention that only pirates are allowed to use turns on that day?
Oh, and they win.
The 90% of the player-base who are not pirates know their place.
Most Lee Harmless wrote:Pirate auto-win : every hit is a win with 500% increase in plunder gained and all the targets ships are sunk and it only costs one turn to raise them!
Did I mention that only pirates are allowed to use turns on that day?
Oh, and they win.
The 90% of the player-base who are not pirates know their place.

Most Lee Harmless wrote:Pirate auto-win : every hit is a win with 500% increase in plunder gained and all the targets ships are sunk and it only costs one turn to raise them!
Did I mention that only pirates are allowed to use turns on that day?
Oh, and they win.
The 90% of the player-base who are not pirates know their place.

, no one mentioned NPC's. What if the day was focused on the prize fighting style event that Will suggested and for this one day, all NPC's swag bonuses are doubled/trippled to make up for non traders loss of revenue? Now that is double or triple before voodoo is cast 

Haron wrote:Pirates across Avonmora reluctantly had to accept that April 12th, 2021, there would be no plundering. Merchants would sail safely that day. However, the pirates expected to get something in return. This year, there would be no plundering on April 12th, but to make up for that, there would be a LOT of plundering on April 12th the coming years. This way will forever be known as the Plunderfest!
Suggestion: On April 12th, to be called the "Plunderfest", plundering only costs 2 turns, instead of the normal 4 turns.