If I am remembering correctly, Mr. Bidini accused Gord of plagiarism regarding The Wreck, and then, when given a chance to clarify his remarks, declined to do so.
Gordon later said that he had based the melody on classic old sea dirges, which makes sense, given the subject of the song. That is a long way from plagiarism - taking someone's creative original work and claiming it as your own - which is, for an artist, the unpardonable sin.
David, I have found this forum to be a wonderful place full of friendly, knowledgable, and generous folks. You and your questions are more than welcome here