Marine Performance

Facts About Performance

• Antiventilation Plate: is the plate directly above the propeller. The purpose of this plate is to eliminate or reduce surface air from being drawn into the propeller. Surface air drawn to the propeller causes cavitations/prop slippage when the engine’s antiventilation plate is too high the propeller will increase slip when the plate is too low it causes excess drag and bow down attitude.

  Position of the antiventilation plate in relation to the hull is crucial for optimal performance.

   

  Antiventilation Plate

   

• Propeller: First we need to understand that the interactions of the water, propeller, and hull with each other are so complex that no one really understands exactly what is happening. However, understanding the complex propeller geometry provides great advantage. There are numerous style propellers some will have effect on bow lift while others can cause stern lift.

  The boat’s weight distribution is directly related to the type of propeller. For example a boat that is heavy forward of the center of gravity (walk around) versus a center console; both require different style propellers. The walk around requires a bow lifting propeller, while the center console requires little or no bow lift. Cupping a propeller in the right area can provide bow lift, or have an effect on pith.

  Inboard Boats usually require greater stern lift some inboard applications can benefit when rudders are adjusted for the need.

   

  Inboard/Outboard Propellers