is one piece episode 4 filler?

The burglar girl's dinghy is discovered by three Buggy Pirates while at sea. Pretending to be a desperate, stranded woman, she lures the pirates on her boat with promises of treasure.

However, she secretly boards the Buggy Pirates' boat and sails away from them without their knowledge. The ship the pirates are on capsizes from a windstorm.

Meanwhile, Luffy and Zoro sail towards their next destination, but Luffy loses his signature straw hat when the boat jostles. Zoro recovers the hat, and its significance to Luffy is explained.