Defuser ring facts,,...

defuser rings were designed for through hull exhaust boats.... it is fact that they cause a loss of top end speed, loss of 1 to claims of 4mph can be gained by running the same prop without it...

but...some boats struggle to get on plane... so the ring helps the prop bite better on take off

the ring design stops air from getting forward to the blades...causing a cavitation ....works kinda like a stall converter on a car... without the ring it's like trying to go up hill from a dead stop in the rain... or worse yet.. on ice... so...like a car with different tires....props play the same roll..

getting a boat propped right is a very fruitful experience...gratification is there with a great big smile ...