just remembered an old trick my mate used to do if he had to cut off his anchor, some might find this silly, others might think it is a good idea, so here goes, he used to get the rope as short as he safely could, then tie a Snapper lead to the end, near where he was going to cut it, when cut, the snapper lead would take the end to the bottom, this prevented slack rope floating about on the surface, if you cut it at high tide, when the tide is low, there could be a couple of metres of rope floating on the surface, waiting to get tangled in someone else's prop.