Does Water Depth Affect Marine Propeller Resistance and Cavitation?

[copria]

Is there a noticable diffence in torque required to spin a marine propeller at a constant rpm (say 2000rpm) when under a different water column? (5m vs 35m)

 

[mgb_phys]

Not much, water isn't very compressible.
ussually the problem is running them near the surface, the impact from air onto the surface of the water causes cavitation.

 

[russ_watters]

note, however, that cavitation is reduced with depth because of the pressure.

 

[copria]

If I want to optimize the energy release from cavitation would it be better to have a shallow water column (producing larger amounts of cavitation) or a deep water column (larger force collapsing the cavitation bubble)?
or
Would both cases yield the same energy release?

assuming the propeller is at a constant speed

 

[russ_watters]

Energy release? What energy release?

 

[copria]

thermal energy release

 

[russ_watters]

You mean you want to eliminate cavitation, right? Higher pressure reduces/eliminates cavitation, reducing energy/efficiency loss.

 

[copria]

No, I want to create cavitation (like a cavitation water heater).

Sorry I did not specify earlier.