Join Date: Sep 2009
Location: Kingston Washington
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Re: Cal 35 MKII with Campbell Sailor
FYI there's a curve in Gerr's book of the optimum pitch/diameter ratio. Gives min,average, and maximum values based on boat speed. Speeds we go at are at the bottom of the curve so for example at 5 kts the values are: .575, .7, and .825 respectively. At 7.5kts the values are .625,.775, and .9. Props should fall in between the min and max. If they fall outside the curves and you can't correct it with a different diameter prop, then the shaft speed isn't suited to the boat and the boat should have a different reduction gear.