Erik Springelkamp offers a set of free wargames rules for 16th to 19th Century Naval Wargames.
David Manley offers Victory At Sea – General Chase! a set of free wargames rules for the Age of Sail.
Jim Gandy offers Camp Cromwell Rules For Naval Warfare In The Age of Sail. The author writes:
The rules are designed for multiplayer games with each player commanding a squadron of a few ships. We mostly fight small actions of 2 players & about 5 ships a side – which take an hour or so. But the game goes quickly, so large fleet actions are perfectly feasible, if you have enough ship models & a big enough hex grid.
The principles of the game are:
1. The game is played on a hex grid.
2. The ship models are mounted on magnetic bases with a paper overlay with washers used as sliding counters to record damage
3. Each squadron has log to record proposed maneuvers. These too are magnetic boards with paper overlays. The proposed moves for each turn is recorded in secret by positioning magnetic counters for each ship on a small hex grid on the log. Details of ammunition type & reload status are also recorded here in secret.
4. All the ships are then moved simultaneously in accordance with those orders.
5. Firing of broadsides is then adjudicated for all ships, usually simultaneously.
6. Finally, boarding actions are resolved.
The skill in the game is the need to second guess the enemy, work out where he’s going be at the end of the next move phase & get your ship in a position to fire at him with the optimum ammunition loaded – and to avoid that fate yourself – in particular to get & to avoid raking fire which is particularly effective.
Empires of the Seas is a set of rules for the Age of Fighting Sail. The author says that the rules allow battles between large fleets without lots of record keeping.