Fujairah, UAE (CNN) There is no mistaking the ugly gash ripped in Andrea Victory's stern.

From aboard a tugboat, rising and falling with the light swell of the Gulf of Oman, I could see part of the ship's steel hull gaping like a ripped-open tin of sardines. Water swirled in and out, the jagged hole big enough to swim through.

At 183m long, 32m wide, the Norwegian-flagged tanker is not the biggest of the 140 ships at anchor near the Strait of Hormuz off the port of Fujairah on Sunday, but it is typical of the international flotilla that uses this geostrategic chokepoint as a maritime parking lot.

The MV Andrea Victory had arrived at noon on Saturday, its crew resting following a two-week sail from South Africa. They were waiting to fill up its near-30,000-ton tank when what appears to be an explosion ripped open its side.

Early in their investigation Emirati officials suggested the hole could have caused by a rocket or missile. Since then, with US help, they have concluded it may have been a caused by mine or improvised explosive device attached to the side of the ship.

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