Motor Tanker “Hoyo-Maru” in a State of Hogging Perfectly Restored

Abstract

Hoyo Maru which was built by the Yokohama Dock Company as an up-to-date tanker was completed in November, 1936.She was grounded on the beach of a coral reef island during a storm in January, 1937, with a full cargo of oil.After her grounding, severe storms came along several times in close succession, and the ship rolled and rolled on the ground of the coral reef. Consequently, she was badly damaged and broken all over her bottom. Moreover, the bottom parts of the bow and stern sank into the crashed sand of coral reef, as they were shaped like wedges and were easy to get into the sand, while the bottom at the middle part was flat and remained on the sand.Thus the storm deformed the ship into the state of “Hogging, ” and the deformation at midship was 24 inches upward at upper deck and 40 inches upward at keel. Ship's shell on both sides buckled and cracked vertically at midship. But the ship was salved successfully after two months' efforts, and she was brought into dry dock. Sufficient number of wooden blocks were built by divers on the dock bottom in water to support the ship on her irregularly damaged bottom and the heights of all the blocks were adjusted to touch the different parts of the bottom at the same time when the ship was lowered down to her position by pumping out of the water in the dock.Special device was adopted for stretching out the contracted bottom lengthwise with gradual lowering down of the ship's body and also for sliding the bottom outward gradually at both ends. The repair job was completed in a dry dock and the ship was restored to perfect condition in 180 days after the job was commenced.