let's theory craft for a moment. let's say you are a time traveller and a naval architect to boot. you decide to go back in time to the 1780s-90s and get a job as the master architect of your respected navies. what changes could be made to the traditional ship's design to make them more effective for the combat of the time?
now I'm not talking about building better guns, you're an architect, no gunsmith. and for the sake of keeping it fairly not crazy, let's restrict it to wood only, the iron industry hasn't taken off, no iron-hulled ships.
Off the top of my head, I could see bilge keels being useful in stabilizing taller Ships of the Line in rough weather.