Chuck, > It's the first time I've heard of changing the prop pitch for conditions. > Did that work out for you? Was it worth the trouble?
For me it is a qualified yes, it was worth it. The qualification is the payoff was much better when delivering boats between Hawaii and the PNW with the plan to cut the corner of the NE Pacific High to save hundreds of miles by motoring for several days. Most of the boats were raced over and did not carry enough fuel for the shortcut strategy. We would carry extra fuel in bladders or jerry cans on the deck. Fuel consumption became a key performance metric. Running out of fuel or having an engine failure in the middle of the NE Pacific high could add weeks to a delivery. (Several of my better sea stories were created by engine failures between Hawaii and the US west coast.) Calypso has a 1991 Perkins 4-108M spinning a 19” 3 bladed MAX prop. From my pitch study notes, using PYI’s estimates 20 degrees of pitch would allow the engine to reach its max 3600 rpm, 22 degrees = 3200 RPM. My goal was to be able to motor, in calm conditions, at 7 knots with the engine turning over between 2400 and 2600 RPM. (At 2400 rpm the vibration / noise vs speed ratio is tolerable. New engine mounts added later helped both vibe/noise substantially.) After several test runs in 1999 we decided to go slightly over pitched at 22 degrees. In 2007 while preparing for our trip around Vancouver Island I decided to drop the pitch setting to 20 degrees which allows to engine to reach its full 3600 rpm with out spewing black smoke. My goal was to insure the engine could deliver enough horsepower to punch into bigger seas and wind if needed on the west side of Vancouver Island. Calypso’s fuel consumption increased a little if we powered up to 7 knots, was back at best fuel efficiency at around 6.7 knots. MAX Prop / PYI is selling a prop model named ‘Easy” that can be easily adjusted while in the water. I have not owner one (I have bought 3 different MAX Props, all the “Classic” model. I think there was one on a boat I helped deliver to San Francisco but we had so much wind that we avoided significant motoring hours. I did not get a chance to play with the pitch adjustments. Good luck on helping your friend on setting his MAX prop pitch. It is my opinion that for most coastal/seasonal engine use getting the original install pitch close enough to allow the engine to reach its rated RPM w/out black smoke is a great place to start. After the first season the owner can decide if a one setting up or down would be better. Stay well, Martin DeYoung Calypso 1971 C&C 43 Seattle/Port Ludlow
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