ventilated props ?

[yipster]

from Boattest.com ventilated props (http://mfile.akamai.com/12689/wmv/boattest.download.akamai.com/12689/_dld/maats/powertech_acceleration.asx)?
reminds me sort of the yamaha props that could break and reverse better by reversing the exhaust flow
but this sounds even better, where do we start drilling?

[redtech]

these props are used a lot on bass boats
mercury makes one that has inserts so one can change the size of the vent for better performance without having to drill

[StianM]

A simpe idea, but dos it work?

Expecting members to try it out:D

[jehardiman]

Should work. It will reduce the delta-P between the pressure and suction faces during high caviatation. On the other hand it will lower rho in the non-cavitating region and mangle the ability to back. There was some expermental work in the 50's and 60's on similar stuff for big wheels, too complicated to justify. Better performance gained by going to slightly bigger, slower turning wheels.

[redtech]

these props do work when used correctly
examples of this prop are:
yamaha -performance 3-blade
mercury -typhoon and lightspeed
evinrude -raker and rakerII
i've also used them on some go fast I/O's not just outboards

[kach22i]

I don't get any sound in the video (old computer).

I did see what looked like a hole which could provide air or a water jet flow over the blade.

How does it work?