PerfectPitch Propellers

[stevethompson]

Was wondering if anyone has had any experience with PerfectPitch props. I currently co-own a 12,000 lb. 30ft full keel cutter rig with a model UJ atomic 4. Current prop is an 11d x 9p bronze 3 blader. After an "interesting" experience in a storm last season,ie, being stalled by the head-seas, I am looking for a lower pitch prop. Motor runs well, but was unable to maintain rpm in above mentioned conditions. Thanks in advance

[RichH]

.... more a comment about the Atomic 4. Most builders severly over-pitched the props when applying to A4s. The A4 is capable of turning 3000 rpm at max output. Its very happly to ''cruise'' forever at 2200. So if you cant reach these rpms it would suggest that you need a vastly smaller pitch, otherwise the engine will ''lug'', never develop its full HP, and wind up with ''bodaceous'' cylinder pressures and connecting rod stresses. Dont remember if the UJ was direct drive or not... and that would make a difference. Depending on the year built... many A4s will benefit by putting a stainless steel ''insert'' between the head and block (with 2 head gaskets one on each side of the ''insert'') to reduce compression. When repitching an A4, be sure that you have the max rpm at full load recorded to discuss with any prop vendor so that you can increase the output (engine) to ''normal''. Just an unsolicited 2˘.
Hope this helps.

[stevethompson]

Thanks for the input Rich. Current prop was on the boat at time of purchase. Always suspected it was over-pitched. PerfectPitch advertises a prop for A4 that has variable pitch depending on load. Design allows blade flex under varying conditions, but am reluctant to try without talking to someone who is familiar with this product. Model UJ A4 is direct drive. Almost wish it was gear reduction. Would expand the horizon of possibilities a little. Thanks again.

[Constantin]

Also try Autoprop. Same idea (variable pitch) may be cheaper.