Forge V3 Lab Finish 21-23p

Lab Finishing

If you have a performance boat and are looking for the optimum you may consider having your propeller blue printed / lab finished. Both lab finishing and blueprinting refer to the process used to insure the accuracy of the propeller rake angle, pitch, progression, pitch variation and cup. Most propellers will have manufacturing variances to some degree so if you remove these inaccuracies it will help to improve performance. Blue printing is a hand process which involves thinning the blades and sharpening the leading edges. The advantage of blueprinting is that it reduces the horsepower required to turn the propeller and generates more usable horsepower for thrust. The disadvantages of this same thinning and sharpening are reduced blade strength, fatigue resistance, and being more subjective to stress risers occurring at the sharpened leading edge. A sharp leading edge is very prone to minute nicks which create stress risers. These stress risers often propagate cracks that originate from the nick at the leading edge and work their way through the blade. The same thing is true for any nicks at the trailing edge. Consequently, there is no warranty for any propeller that has been lab finished or blueprinted and this must be considered when weighing the advantages and disadvantages so you can make an informed decision.