WAR BY SAIL:
I like to work in a "Simple yet accurate" aesthetic. I start with lots of research and reading of first-hand accounts, then build up simple mechanics to handle what happened.
This system will probably aim at 5 - 20 ships per side, covering all the major naval conflicts from 1550 - 1815.
I want to give players more granularity on the armaments of each ship, to add more historical flavor; Individual named ships will have full lists of the exact guns they carried, and the facing of those guns. Players will roll for each gun to inflict hits and damage, rolling all the same type at once (like all 24-pdrs, or all Demi-Culverins at once).
This way you roll a bunch of dice when you fire a broadside, so it feels like you're really unleashing hell.
As well as lists of individual named ships, there will be generic ship lists, for people who don't want to worry about specific names, or want all their Third Rates armed the same, etc.
All the usual mechanics in Sailing will be represented: Boarding, Warping, Boxhauling, etc. and I have a simple Sailing mechanic based on a single template lined up with the wind direction. Sailing works in a way that will cause collisions if you're not careful about where your ships are facing...
There are no ship data cards, so damage is handled with a minimal number of markers placed directly on the ship's base.

The Sailing Move (a mandatory forwards move) is done simultaneously, after which players roll off to see how many ships they can activate. Activation then alternates between players, ship by ship. If one player runs out of activation, they can only do minor actions like turning instead of being able to have full control and do things like turns & attacks at the same time.