Fire continues to be one of my strongest openers in any sea-battle. I see almost no one use a cannon-shot firebomb...yet your ship will look like these after a few of them hit you.
And don't be fooled. It's a lot harder than you'd think for any crew to manage a fire while also getting hit with chainshot or, my new personal favorite, blunderbomb shots from a cannon.
Those things pretty much wreck any crew, letting the fire cook nice and good.