This certainly looks like a landing gear strut, with the tire imbedded in the reef. Makes sense to me that the surf would have ripped the airframe from the strut, and then the strut from the reef, especially if a storm had moved over the island.
Personally, I think that you'll find parts of the Electra just off the reef, and will be able to recover something. This photo matched against the others that you have means that there is an "amomaly" on the reef, north of the shipwreck, and probably not part of the ship. I hope that you find it!!
Tom