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cavitation at top speed

C

cbelk

Member
I have a 17 ft sylvan aluminium hull fishing boat with a 75 hp merc, at top speed 43mph the bow cavitates badly when I back off the throttle to around 36 mph it smooths out to almost perfect. would a hydrofoil help this or does anyone have any other suggetions. Thanks
 
Lowering the motor a bit, or adding some cup to the blades, will cure that. I personally don't like hydrofoils--they tend to break cavitation plates.

Jeff
 
Why does people thing it's cavitation plate, when isn't. Correct name is Anti-ventilation Plate: Large plate cast into gearcase housing directly above propeller. Helps reduce surface air from being pulled into blades....

Cavitation: The aeration (bubbling) and boiling effect of water caused by creation of a low pressure area. Generally caused by a solid shape (propeller blade) passing through the water, in such a position and speed, that a low pressure area is formed due to the inability to move through the water in nonresistant manner. An example is, a propeller blade that has a rough edge would not cut efficiently through the water, thus creating a low pressure area. If the pressure drops below the vapor pressure, a cavitation bubble will form in that region. These bubbles will collapse when they reach the higher pressure region of the blade. This causes a rapid change in pressure and can result in physical erosion. You may notice burns (erosion) at some area on the face of the blade.

Steve​
 
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