On the trailer or on the lift, center plug comes out when it is not in the water. We have established a routine where before every outing, lift the dog house and among other things to check, grab the center plug from the top of the manifold and install it. Pull it at the end of the day when in the lift or when going back on the trailer and toss it back on the manifold. Never moves and is always part of the pre launching check. I hate water in the bilge, especially with a wood stringer boat.
'86 Comp TS6M - Reborn 2016
Riding a HO Sports CX Ski