Stus-List Re: MAX Prop pitch discussion
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 43 Seattle/Port Ludlow Thanks to all of the subscribers that contributed to the list to help with the costs involved. If you want to show your support to the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
Stus-List Re: MAX Prop pitch discussion
Adjusting prop pitch for conditions is very much a thing in airplanes and some larger boats and ships. In some cases changing pitch is how you reverse. I think SAAB used to sell a little one or two cylinder diesel for sailboats that could move an amazingly big boat for a tiny engine due to the controllable pitch prop, as in controllable from the cockpit. Joe Coquina From: Chuck S via CnC-List Sent: Monday, December 28, 2020 9:57 AM To: Stus-List Cc: Martin DeYoung ; Chuck S Subject: [EXTERNAL] Stus-List Re: MAX Prop pitch discussion Hi Martin, Thanks for your detailed response regarding MaxProp and PYI. Great advice as always. 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? I'm still looking for "actual settings" by owners with a C 34/36, two blade 17" prop with a 2.6:1 reduction. I'm trying to help a friend (who just bought the prop) avoid trial and error. Chuck Thanks to all of the subscribers that contributed to the list to help with the costs involved. If you want to show your support to the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
Stus-List Re: MAX Prop pitch discussion
Hi Martin, Thanks for your detailed response regarding MaxProp and PYI. Great advice as always. 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? I'm still looking for "actual settings" by owners with a C 34/36, two blade 17" prop with a 2.6:1 reduction. I'm trying to help a friend (who just bought the prop) avoid trial and error. Chuck > On 12/27/2020 9:29 PM Martin DeYoung via CnC-List > wrote: > > > > Chuck, > > > > I have used MAX Props since the mid 80’s including multiple Hawaii > crossings. (Full disclosure, I have known Frederic Laffitte one of PYI’s > owners since before PYI was a company and have sailed over 20K offshore miles > with him.) > > > > I echo the comments regarding PYI’s recommendations, especially as a best > starting point. Fred Hutchinson has been serving PYI’s MAX Prop customers > for a very long time. I have been at PYI and been able to observe their > customer service commitment first hand. Last time I was there it looked like > the next generation was beginning to “learn the ropes” from Frederic and the > other owner/managers so us MAX Prop users should have them as a resource for > a long time. > > > > For Calypso’s 3 blade MAX Prop and on other boats I have used several > different pitch settings. For long off shore voyages I have intentionally > over pitched the prop (just a little) to reduce engine RPM when motoring in > calm (NE Pacific high) conditions. For our trip on Calypso around Vancouver > Island I slightly under pitched the prop to allow better power (higher engine > revs) for “punching” into head seas and wind. > > > > If you do not hear from someone with your same boat and power setup, > using the PYI recommendation for your first time underway then looking for > the usual signs of over/under pitch may be the best compromise. When I was > experimenting with Calypso’s prop pitch I had a deal with the Travel Lift > operator that he would leave the slings down long enough for me to perform a > “hot lap” and check the performance. I got away with this twice before > settling on my best 2 options. > > > > Happy New Year and stay well, > > > > Martin DeYoung > > Calypso > > 1971 C 43 > > Seattle/Port Ludlow > > > > Hi guys, > Tables are great, but actual settings are better. > I hope someone else with a 36 footer and a Yanmar 3GM30F w 2.6:1 > reduction and a 17" two blade MaxProp will share his actual setting number to > help us. > > Thanks to those who responded already. > Chuck S > > > > Martin DeYoung > > > > Thanks to all of the subscribers that contributed to the list to help > with the costs involved. If you want to show your support to the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu > Thanks to all of the subscribers that contributed to the list to help with the costs involved. If you want to show your support to the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
