Duck Diving Technique on a Wide and Thick Fish Surfboard

Hello Surfers of the Internet,
I find duck diving my fish a problem. The dimension of the fish is 5'10" x 21 1/8 x 2 9/16. Yes, it's wide and thick. I'm 5'10" and 144lb. I ride all types of boards which is probably why I haven't practiced my duck diving enough (I turtle-roll on bigger boards). I do okay if the wave hasn't broken or is just about to break. However, when it has broken, the white water gets me most of the time. I do okay with surfing overall but am self-conscious when I mess up my duck dive while other surfers scoop right under the wave. I also don't want t turtle -roll the fish, but I do sometimes because I'm pretty good at that. I suspect my problem is the wide tail of the fish which I can't sink fast enough. I have also attached the photo of the fish herein for reference. Please provide some pointers.
Thanks!
I find duck diving my fish a problem. The dimension of the fish is 5'10" x 21 1/8 x 2 9/16. Yes, it's wide and thick. I'm 5'10" and 144lb. I ride all types of boards which is probably why I haven't practiced my duck diving enough (I turtle-roll on bigger boards). I do okay if the wave hasn't broken or is just about to break. However, when it has broken, the white water gets me most of the time. I do okay with surfing overall but am self-conscious when I mess up my duck dive while other surfers scoop right under the wave. I also don't want t turtle -roll the fish, but I do sometimes because I'm pretty good at that. I suspect my problem is the wide tail of the fish which I can't sink fast enough. I have also attached the photo of the fish herein for reference. Please provide some pointers.
Thanks!