Surfing Waves

Hi all, new here.

I consider myself an intermediate surfer, I ride a 6" 0' Rusty Piranha. (I love it)

I've been trying a few different fins and have always found the tail end of the board washing out or slipping.

I've tried:

Grom fins (Not very helpful lol)
WCT
YU

I don't weigh very much (135lbs depending on what I had for breakfast , I'm 5' 11")


Any reccomendations for fins? Or suggestions as to what I need to work on? It's a thruster set up


Thank you!

I wonder in what situations does it slip? I am an older surfer who used to surf single fins long ago. When I started with a thruster I found it slipped sideways a lot in turns. I now surf a quad and if I push it hard it slips in turns but not in bottom turns. However lately perhaps because I am no longer putting maximum pressure in the turns it is all a lot smoother and quicker. Not sure why that is. I think I am just getting used to the board but it all came about when I started getting my hips into the turns. You see high performance surfing is all about changing your center of gravity which is ultimately controlled by your hips. No answer for you but if you are slipping in bottom turns then maybe you are too forward on the board. Back when I had a three fin board I got a bigger center fin so it was like a single fin but I still slipped in turns however then I started to like that so I quit trying to change it. I have been working on my cutback and think I am close to getting that down but I have to turn around my center of gravity instead of relying on the rails and fins to hold the turn. If I push really hard the board pops out of the water and slides and the board goes flat to the wave losing the rail. Maybe I am pushing to hard on my front foot? Anyway for now I am doing more balanced and perhaps graceful turns as opposed to my muscle memory for power turns and it's working.