Weapons on pirate ships and British ships were basically the same, with a few notable exceptions.
Grenades a.k.a. smoke bombs
Blunderbuss a.k.a. a little bazooka with a whopper of a kick
Rapiers a.k.a. short, sharp swords that are thrusting weapons
They both shared ships
They both had cannons, cutlasses, pistols, daggers, and long swords
The pirates had schooners, brigs, brigantines, cutters, ketches and sloops, and frigates were used rarely.
The Navy had frigates and fishing smacks and the same kinds as pirates.
The Navy had the Union Jack
The pirates...anything they could get but mainly the jolly roger