Propellers:
Space available to fit the propeller is somewhat limited by design. Without modification to the hull it will be difficult to fit anything bigger than a 17“ propeller, usually about the minimum for gear box ratios available to the market today. This will provide not more free space than some 1“ max between the tip of the propeller blades and the hull.
We and others have chosen a 3-blade 17“ MAX-PROP. This propeller is ideal when changing from the VOLVO PENTA B-series engines originally installed to newer engines-types. The MAX-PROPp can be adjusted to work both directions. The VOLVO B-series engines were often fitted with the so called RB-gear box which made the propeller spin in the same direction as the engine crank-shaft, ie opposite compared to today’s gear-boxes (the RB gear box was direct-driven). Given the rather small aperture for the propeller to spin it might be sensible to stick to engines up to 30 HP to be able to fit the right propeller but to avoid bigger engines as it will be difficult to transmit the added HP into the water.
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![Fitted with Max-Prop](files/jm2009-02.jpg)
Photos Courtesy of boat owner