Most pros recommend about a pound of anchor weight per foot of boat for offshore fishing.
An alternative is to add some stout galvanized chain to your anchor line. And going to more scope also helps. Let out five times the water depth routinely, or more if the wind and current are exceptionally strong. Frank's Tacklebox is a forum for readers to address Tribune Outdoors Editor Frank Sargeant with questions and comments concerning the great outdoors. Letters should be brief and signed by name.