If the flipper had a smooth leading edge, the whale would be unable to make such tight rising turns because the water would churn and eddy behind the flipper and cease to create lift.
Juhul, kui loiva esiserv oleks sile, ei suudaks vaal selliseid tihedaid tõusuringe teha, sest veekeeris moodustuks loiva taha, mis aga oleks tõstejõule takistuseks.