In 1978 after sailing out to a reef after a storm I found a 12 inch iron spike encrusted in coral. It was just on the edge of the reef with deep water on the other side. By the looks of it the reef had been hit by a propeller and broken the spike out of the reef also shattering the coral off the rest of the spike except for the top end. The spike is 3/8 by 3/8 inches square with a wedged end. I think that this spike was deposited due to a collision with the reef rather that floating in attached to wooden parts of a ship as the reef is submerged at high tide. I’ve included some pics any info on it’s possible origin would be appreciated.