I think it's called tandem. The idea of putting two anchors on one chain, one about 10 feet behind the other. I've tried it a couple of times on difficult bottoms and it worked pretty good. Once was at 'French Cay' near the Turks and Caicos. The bottom was hard flat bottom under 3 inches of sand. Impossible situation but it held, perhaps just from all the junk on the bottom.

Of course, if you snag a tree you won't get either up.