Pirates usually wore what they wanted and there was no dress code aboard a pirate ship. However there were two essentials. A good sturdy pair of seaboots and a well fitted tricorn.
The tricorn kept both the rain and the sun off your head and it kept the sun out of your eyes when you were scanning the horizon.
The boots kept your feet dry when the waves were crashing on the decks. These particular boots have very hard protective toecaps, which are handy if your toes got run over by a stray cannon of if a clumsy gunner dropped a cannon ball on your foot.
