Anyone have any knowledge of cavitator plates used on larger inland tow-boats? Twin screw, strut-stern configuration with a “V” shaped shaft support. I am looking to reduce hull vibration caused by the pressure forced from the wheel cavitation. From what I understand, it will create a pocket of air against the hull above the wheel to dampen the forces acting directly on the hull itself.
Having ridden this rodeo before, the plates you are referring to are flat plates welded to the top and bottom of the rudders to try to ‘capture’ any wheelwash flowing over or under the rudders while manuvering. I have heard of this being desirable to stop cavitation while manuvering. BUT, during normal running, the cavitation is most likely due to:
prop tip clearance issues,
hull and frame wastage (weakening the hull around the props)
or shoddy alignment/ cutlass bearing installation.
Can you imagine how difficult it would be to ‘keep’ a water barrier under the hull, while moving, while having water flow continually scrubbing said air pocket?
If you look in the trade magazines, occasionally there is mention of some air induction technology to reduce hull friction, or air to reduce transom separation. But I think you have been hearing of ‘old wives tales’ concerning the air around props. Generally air around props is hugely detrimental to their efficient operation.
I think your issue is: pushing many hundred feet of barge in front with several bow rakes and stern rakes entraining air ( all those bubbles) is causing the air to flow to the prop, causing most of the vibration. This is just part of the business. However as I said earlier, poor hull condition and improper alignment is a major contributor to this vibration.