So I did not have time to figure out a proper ship combat/sailing system before my first D&D game with a ship combat in it. I fudged it and I think it went OK, but I definitely don't want to be making it up as I go along every time. So here are my thoughts. I want the following to matter in ship actions:
- Where a ship gets hit: masts/rigging? Hull? Below the waterline?
- Manoeuvre: in particular, turning in combat is tricky for sailing ships.
- Decisions made by PCs: rallying/commanding, steering, shooting, and of course magic.
I think the easiest way to do this is to give each ship a little character sheet, like the ones in Man o' War:
This example, taken from R. Fuller's Man o' War page, is easier to see.
There are also no skills that reflect the different things ships can do, which on the one hand is a good thing but on the other means we run the risk of a single skill becoming dominant. So here's what I'm gonna do:
- Separate ships into bands: high/medium/low as above. Allocate damage effects to each band. Maybe if you exceed a certain damage threshold, or on a crit, you create some special damage effect like killing a vital crew person. I would assume that typically imposes disadvantage on whatever it is that part of the ship does. Like, kill the helmsman, disadvantage on steering or whatever.
- Give ships proficiencies. So instead of using characters' skills, we use characters' stats but ship proficiencies. For instance, let's say the skills are: Tack/Wear, Chase, Ram, Board/Grapple and Broadside. Galleys are good at Ram and Chase, big battleships are good at Broadside and Board; basically each skill is a maneouvre and certain ship designs are good or bad at them.
- Allocating PCs to a certain station on a ship helps you do something cool with them -- tops, helm, sick bay, guns, whatever. Maybe just allows them to roll their own stats or something, although that might not always be a great thing. But it would certainly help figure out where everyone was. So maybe the character sheet is a little mini-map; put a figure on that area of the ship, that's where the character is.
- Obviously the PC ships are going to be more detailed than the NPC ones.
I guess the real question is the skill list. I like the ones I've listed; tight turning, fast pursuit, and some different combat actions. I don't know if there's anything I'm leaving out.