Warship Island Arc

The Warship Island arc, sometimes referred to as the Apis arc, is a story arc in the anime One Piece. It is the first story arc of the series not to be based on any content from the manga by Eiichirō Oda. It was left out of the 4Kids dub.

Summary
This arc takes place just after Luffy receives his bounty of 30,000,000 Beli at the end of the East Blue Saga, and before the Straw Hat Pirates enter the Grand Line.

The Straw Hats find a young girl named Apis floating in the ocean. She has a Devil Fruit ability that allows her to talk to animals, and she's used it to befriend a dying Sennenryu, a type of dragon species thought to be extinct. She wants to return this Sennenryu to his homeland, but they run into two problems:
 * A Marine fleet is after the dragon also, because it can be used to make a powerful, and valuable, medicine. Their commander (Commodore Nelson), has hired the mercenary Erik the Whirlwind (A Devil Fruit user with claws so sharp, that he can cut the air) to help him get the Sennenryu, but Erik may have his own agenda.
 * They don't know where the Sennenryu's homeland is.

This arc chronicles the Straw Hats' efforts to return the Sennenryu to his home, make Apis happy, and stay out of Erik's way.

Scenes Fitting With the Manga
Despite the Filler status of the arc, the anime manages to incorporate some parts from the manga into it. Most notably the crew accidently sailing into the Calm Belt. In the manga, after finding themselves on a Sea King's nose, it sneezes them back onto the main course. The crew nearly lose Usopp during the flight but Luffy catches him. In the anime, the scene is changed and Apis is the one who nearly falls off after the sea kings reveal themselves. After Luffy catches her, he swings Apis into the sea king's (the one the ships on) nose allowing her to pluck a nosehair, causing it to sneeze and the crew to fly back into safe seas. Also the crew entering Reverse Mountain is incorporated at the end of the arc, in which Erik comes back at the last minute to try and take his revenge on the crew as they go up the slope. Nami, however, trips him off the railing of the ship and knocks him into the water.

Controversy and Plot Holes

 * When the Straw Hats find themselves surrounded by a Marine Blockade connected by steel-chains, Roronoa Zoro says that he can "cut anything" and proceeds to slice through the steel chains. However, later in the canon Arabasta arc, Zoro reveals he cannot cut through steel.
 * Another plot-hole is revealed during the Thriller Bark arc. Zoro at one points out to Ryuuma that he does not believe in dragons, a line that doesn't make sense after seeing Ryuji.

Translation and Dub Issues
In the English dub of the anime, produced by 4Kids Entertainment, these episodes were cut completely from the series. No explanation was given, and nothing (other than their irrelevance to the main plot of the series) would seem to be just cause for dropping them from the show entirely. Since their content is much more "kid-friendly" than the rest of the series, many fans actually expected 4Kids to heavily promote the arc, but the exact opposite happened. The precise reason for their deletion from the run of the English-dubbed anime remains unknown.

Trivia

 * Warship Island arc is the very first filler story arc in the series.
 * Like other fillers, the Warship Island arc received its own manga adaption in the form of a "novel."