YO-257

For decades this plain workboat carried fuel around Pearl Harbor's piers, one of the unglamorous yard oilers that kept the fleet running from the Second World War era onward. Her second act is far more public. Purchased by Atlantis Submarines and scuttled off Waikiki in 1989, the roughly 53-meter YO-257 was placed specifically to give the company's tourist submarines something to circle — which means divers on her deck routinely look up to find a 48-passenger submarine gliding past, faces pressed to the portholes, everyone waving at everyone. She sits upright on a flat sand bottom at about 30 meters, cut with large access openings, her rails thick with encrusting growth. Green sea turtles treat the wreck as a rest stop and can be found dozing on the deck plates; whitetip reef sharks tuck under the hull; bluestripe snapper — the introduced taape — swarm the superstructure in yellow rivers. A second wreck, the smaller San Pedro, lies within an easy swim, and most operators run the pair as one dive. As an easy, animal-rich introduction to Hawaiian wreck diving, she has few rivals.

沈没の経緯: Deliberately scuttled as an artificial reef off Waikiki, 1989.

コンディション: Upright and intact, heavily encrusted; access cuts keep the structure open and bright

洞窟貫通（ペネトレーション）: Limited. Large cut openings allow straightforward swim-throughs of the main spaces; overhead time is short and well lit, but training still applies. オーバーヘッド環境への進入には専門的なトレーニングが必要です——最低限、レック・ダイビング認定資格が必要で、完全貫通には技術的なレック・トレーニングが求められます。

推奨ライセンス: Advanced Open Water

流れ（カレント）: Mild · 透明度: 15–30 m

海洋生物: Resting green turtles, whitetip reef sharks under the stern, clouds of bluestripe snapper, spotted eagle rays over the sand, and octopus in the fittings.

危険生物・リスク: Submarine traffic overhead — stay with the wreck and your group; depth on the sand