Not to scare people, cause I still like the scupper, but one time on a pretty good size bail, I heard a wooshing and clicking sound as my ski sank. I got there quickly and got it flipped over, but that was the first time I thought about the air displacement issue. If I had a regular pole etc, it would have been better. I have actually thought about installing foam in my pole, but just put some in my pancake foothold instead. If you remove some foam, from a stock hood, pole, etc. you may be a lot worse. Like I said before, it's a love/hate for me, just don't let go!
