Development of novel folding propeller for sailing yachts

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According to Sailing Today Magazine (Sep 2011), fixed blades propellers are known toreduce speed “under sail” by a considerable 0.5-1.0knots. Therefore, many sail boat ownersuse folding propellers, as they minimise the unwanted drag induced on a sailing boat. Despitethe predominance of folding propellers in the market, there are a number of issues associatedwith the folding propeller that prevent it from fully satisfying the needs of the sailingconsumer.Firstly, folding propellers have a reputation for losing working parts before the end of theirdesign life, leaving the boat owner needing a replacement device. The weight of existingpropellers is known to affect the life of the cutless rubber bearings contained in the shaftsupport coupling. Finally, since reverse thrust is less than adequate, manoeuvring within orclose to a marina or a berth becomes significantly more treacherous. Folding propellers can beup to 3 times more expensive than standard fixed blade.Super Prop Ltd. is a start-up company, set up to exploit specialist processing technologycapable of producing a novel propeller that can address the aforementioned customer issues.Their concept solution is enabled through a specialist investment casting method developedover 30years by Micro Metalsmiths Ltd. The SuperProp propeller will weigh 30% less than itscompetitors, cost 50% less, have an average extended life of approximately 25%, and willproduce more thrust by having a complex blade shape that is extremely difficult to produce bynormal CNC machining methods.