Here's a list I compiled years ago. Hasn't been updated since 2004 though, so the links may not be correct anymore. There may be more rules sets available since.
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PIRATES RULES
(Some readily available; some hard to get; some OOP.)
"Privateer" by Steve Winter (2003)
Skirmishing during Piracy's Golden Age. Designed for 25/30mm figs, one fig equals a single warrior though small scale battles can be fought, scenarios, quick play sheets. Available from onmilitarymatters.com
"Once Upon a Time in the West Indies" by Pete Berry/Partisan Press (1991)
Pirate skirmish rules add-on to "Once Upon a Time in the West Country." Both rules sets required because "West Indies" – mostly ship rules and scenarios – uses the land combat rules in "West Country."
Available through Caliver Books (UK): caliverbooks.com and onmilitarymatters.com (US)
"Treasure Island" by Over the Wire
A set of rules with 25/28mm figures for playing out pirate action and the search for treasure. Contents include rules, 10 character figures, 10 pirates, 2 treasure chests, 1 skeleton bits and a palm tree.
link
"Fifteen Men" by Eureka Miniatures
Designed for Hollywood style action and quick exciting games of piracy on the High Seas, these skirmish rules require only fifteen pirates per side.
eurekamin.com.au/index.shtml
"Pirates!" by Flagship Games
Fun system for 28mm; company sells ships, use whatever figs you want; fantasy crews (elves, dwarfs, undead, etc.); rules and ships can be purchased separately.
flagshipgames.com
"Pieces of Eight" -- 1st ed. by Peter Pig (1994) peterpig.demon.co.uk
Rules for 15mm; very basic system; covers both ship combat and HtH
"Pieces of Eight" -- 2nd ed. by Peter Pig (2000) peterpig.demon.co.uk
Rules for 15mm land; 1/450th naval.
Available in the U.S. through Brookhurst Hobbies: brookhursthobbies.com
"Hoist the Jolly Roger" by Ross Rigby and Neil Morris
For 25/28mm; thorough but not too complex; has random event cards; covers both ship combat and HtH (for ship and land); looks to be very fun and accessible. Only available directly from the authors (in
England; very hard to get mailed to U.S.) Check out the Manchester Area Wargaming Society (MAWS) web page for pics and info at link
"Treasure of Sandheap" by T. Sheil and A. Sheil
A beginner's game for fast play with toy soldiers.
link
"Corsari, Pirati & Bucanieri" by Riccardo Affinati
In Italian; free on website:
link
"Blood & Swash / Thunder & Plunder" by Buck Surdu (Jodie-Press)
link
"Shiver Me Timbers" (OOP) by Village Green
"Davey Jones Locker" (OOP) by Daniel Fox (Sutton Hoo Games)
"Them As Dies Is the Lucky Ones" by Johnson/Ratcliffe (thru Redoubt)
(Cannot find any reference to rules at Redoubt site)
redoubt.force9.co.uk
"Buccaneer, Broadsword & Blunderbuss" by Old Glory
oldgloryminiatures.com
"Evil Stevie's Pirate Game" by Steve Jackson
Free at: io.com/~sj/PirateGame.html
"Strange Grogge" (now Strange Tydes?) by Steve Blease, et al (Wessex Games)
link
"Pirates of Sartosa" (Warhammer system) by [Author unknown]
Free at: link
"Pieces of Eight" by Andy Watkins
Free at: link
"Wooden Ships & Plastic Men" by Mathew Clayson
Free at: link
"Debauchery, Rum and Bloodletting" (Fire & Steel variant)
link
"Jolly Roger" (I have copy, but no designer listed)
Land and sea battles; with special action and event cards
"Pirate Raiders" by Brian Whitaker (Not published; I have copy)
Simple raiding party rules special action and event cards
RULES THAT CAN BE USED WITH PIRATES
(Horse & Musket era, or good rules for other eras that can be retrograded)
"Sacre Bleu!" by [Unknown]
Mass skirmish rules 1660-1830. 25mm Skirmish rules 10-100 miniatures.
Available through Caliver Books (UK): caliverbooks.com and onmilitarymatters.com (US)
"Freikorps" by Bryan Ansell of Foundry
Simple skirmish rules for period from about 1700 to 1850; land combat only; random initiative; roll for hit location on body.
Free through: icenter.net/~gisby/rules.htm
"Rencounter" by Edward Allen
Another system covering approx. 1700-1850; far more comprehensive than Freikorps
Free at: link
"Stand To!" by Steve Winter
Covers small "Colonial Era" battles; very simple, fast, fun system
Free at: link
"Limeys & Slimeys" from Outland Games
15mm Age-of-Sail naval warfare; no land combat.
Free pdf at: PDF link
"Matchlocks on the Warpath" by Jon Lundberg / Historic Enterprises (OOP)
Skirmish combat during "the settling of America"; land combat only; roll for hit location on body; rules look great -- too bad they're for land only.
"Swashbuckler" by Yaquinto Games (OOP)
Man-to-man, phased combat.
"Fire and Steel" – by Mark Evans and Dave Wilson
Skirmish wargames rules 1700-1900
There are numerous Age-of-Sail rules that could be applied or adapted for naval action.