Four relevant keywords, sorted, duplicates out, broken into groups by year posted and approximately 50 topics, irrelevancies removed by hand (political trainwrecks are not 'wrecks', for example; also removed all or most of the Edmund Fitzgerald topics, any modern vehicle or ferry crashes, all Concordia and much Titanic stuff):
Whoops, six relevant keywords — anchor/s, shipwreck/s, wreck/s.