Mercury PVS Vent Plugs
Mercury in solid, large, medium, and small vent plugs for PVS (Performance Vent System) boat propellers sold as 5 vent plugs per package.
On acceleration, exhaust is drawn out of the vent hole. When the propeller blade strikes this aerated water, it pushes through it much easier than it would solid water - causing engine rpm to increase more rapidly. Once you're on plane, the water flows over the vent holes and seals in the exhaust, allowing the propeller to again operate in solid, nonaerated water.
Just by varying the size of the exhaust hole and controlling your engine's rpm, you can eliminate sluggish performance or compensate for changes in load an altitude. And its technology that you can only get with Quicksilver Propellers.
PowerTech Propellers with PVS