im sure i have mentioned this before, why not strip the top for valuables and pollutants
several well-placed and timed bangs to cut the top off the legs at a respectable depth under the surface(marine hazard would be ideal but a bit harsh) to drop the top to the sea bed(or into a crumple with the legs part way down using a few clever cables and placings)
chuck a tyre in the sea and within days something will consider it home
the things living in "captain haddock's jacket" that washed up next to me were amazing, american jacket, landed in kernow, left it in a barnsley nightclub it still had dried shrimps stuck in the lining
wreck fishing by line is a well known way to catch fish, i have had a few good runs when the boaty folk know where to park
when folk have created scrapyard reefs the dramatic increase in biodiversity and biomass can be measured very quickly
a bit like planting a wood on a bare mountain, but faster