Should Both Sides of the Blade be Polished?  Generally speaking, a prop that is polished on both the face and back (including the hub) will achieve the highest possible top speed. There is some advantage to a rough (satin) surface on the back. The reasoning is that It gives more bite for acceleration and helps pop the boat while pulling out of the turns. Really there is very little to no difference between a satin finish on the back of the blade vs. high polish on both sides, until extremely high speeds are reached. So for SAW's polish polish polish, for the rest of us put a very fine satin finish on the back.
Aspect Ratio The relationship between pitch and diameter, is known as the Aspect Ratio, mathematically its the Pitch divided by Diameter. The Octura X435 has a 1.38 diameter and a 1.932 pitch so 1.932/1.38 = 1.4. Generally, a faster prop has a higher aspect ratio or more Pitch, with less Diameter. Installing on a boat  When I put the props on my boat I do two things. First I put a small piece of silicon tubing on after the prop, this does two things. First its more than enough to hold the prop on should the prop nut spin off. Second should the prop hit something in the water it allows the prop to give a bit minimizing damage. After the tube I still put on a prop nut, mainly for looks. I snug the prop nut up finger tight onto the tubing, compressing it slightly.
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