Surface piercing propellers

Surface piercing propellers are manufactured in NiBrAl from:

1. • up to 70" diameter with a power range from 600 Hp up to 5500 Hp.
   

and in Duplex Stainless Steel ERO and 17.4PH from:

1. • up to 28" diameter with a power range from 250 Hp up to 1400 Hp.
   

Propellers are designed from systematic series based on tunnel testing and permit Rolla to calculate torque - thrust coefficients, efficiency and horizontal - vertical force figures for different shaft angles and propeller immersions.

CFD calculations are also performed on this type of propeller (see section below).

The video below shows a moment of the tunnel test. This test has been carried out at the SVA Potsdam Model Basin.

At present Rolla is developing an instrument that shows the details of the flow around the partially submerged propeller. The blade is studied as it enters and exits the water, not only optimizing thrust, torque and secondary forces, but also minimizing fluctuations that cause vibrations and structural damage.

Different physical quantities like pressure, vorticity or cavitation are visualized over the propeller surface and in the field surrounding it.

Click here if you can’t see the video

Click here if you can’t see the video