He must be getting coaching tips from Bozo.
Back when he was coaching, the low placed Bears always seemed to beat the high flying Sea Eagles with their team full of rep players at North Sydney oval. (I can still remember players like Wombat or Boustead tearing up the sideline)
Bozo came up with some interesting excuses for their losses. He once blamed the state of the ground saying that they had trained expecting to play on a hard surface but some wicked groundsman had watered the ground the night before thus disadvantaging his players ...... bwahahahahaha.
So to put some facts around this:
During Bozo's first stint as coach (1983-1988), Manly lost 1 game at North Sydney Oval and won 5.
Given the reference to Wombat and Boustead, I assume this is the period you're talking about.
During the 2nd stint (1993-1999):
Norths won in 1993 (Norths finished 6th, Manly 4th)
Manly won in 1994 and 1995
Norths won in 1996 (Manly finished 1st and the "low placed Bears" finished 3rd)
Norths won in 1997 (Manly finished 1st and Norths finished 4th)
Norths won in 1998 (The high flying Sea Eagles finished 10th and the low placed Bears finished 5th)
Manly won in 1999
I guess history changes when you ignore what actually happened.