Many factors
What's the bottom like ? Rocks need a grappel type, sand $ mud need a flat fluked type like a danforth or a plow. Kelp ??????Go over the recomended anchor size by a size or two. It's heavier but when you really need to hold in bad conditions, you will be glad you did.How much scope is being payed out. Too steep an angle is going to pull out anyanchor. When in doubt, let it out. 6-7 maybe even 8 X depth.We have about 25' of 7/16" chain on a fortress 23 anchor & 200' of 3/4" line on our H-33.We typically anchor in around 20' (MLW. So whenever possible, I let outabout 100' of rhode. I have to date, not had a problem (knock on fiberglass).