It is ironic that I should just get home a few hours ago and check me email and the subject of CPP's comes up. For the last 12 days I have crossed Lake Superior and was fishing at Isle Royale National Park. During that time I used all the aspect of CPP's except one. The exception is the use of a CPP to be used as a transmission. Because the Hundested does not have the pitch range from full feather to full reverse, I can only change pitch from full feather to neutral pitch. I do have a regular transmission before the Hundested box. The reduction gear is 3/1. I noticed in the remarks by Michael Kasten that my type of CPP only goes to 300 HP. My engines are 330 HP. They did tell me I was on the limit. I think I only ran the engines all out twice, which produced 20 knots. A lot of interesting things happen when you want to go fast after running on one engine like I do most of the time. There are so many variables to look at. First the most important is the exhaust temp. The temp must be kept to a reasonable level. I have talked to a lot of people and no one has ever told me just how hot I could let the exhaust get. When I run at 16- 18 knots the exhaust gets to about 850. I noticed someone said something about 700. I first try to balance the engines so both engines are about the same RPM and the fuel burn is the same and exhaust temp equal. As I push the levers forward I watch the RPM, exhaust temp, hull speed and the fuel burn. If I try to accelerate to fast the exhaust temps climbs above what I consider too hot (850). Because of various conditions one engine always seems to carry more load and the exhaust temp climbs quicker. When this happens I have several choices. Slow that engine, reduce pitch or increase the other engine. With experience the process is not too bad. The interesting time is when I find myself in seas that are uncomfortable at my slow one engine speed. The ride is much better at 17 knots in rough seas until the seas get too big to go fast. When the waves react to each hull differently, balancing it all out can be fun. Even with the pitch gages the same it still seems to take balancing. I usually use the auto pilot while playing with all the controls. I know I cause my own problems because I run on one engine most of the time. If you ran with both engines most of the time the boat would operate just like fixed props. I brought up the fact that I was fishing because that is where CPP's shine. When trout fishing one needs to be able to troll from 1.2 knots and up. This could be done with a trolling valve, but the CPPs work to perfection. I feather one prop and then raise the RPM on that engine till the alternator is charging the way I want and adjust the pitch to the speed desired. In one of my postings I said I was going to try fixed pitch props. After thinking about all the hustle and the cost I never did. Now I don't need to as Mike on Chrysalis has given us the details. Wild Wind IV has traveled about 55,000 miles and has used over 40,000 gallons of diesel, which includes the genset and the diesel cabin heater. The engines have about 3600 hrs. If I ran two engines all the time, just think of the hrs. I believe my engines are in good shape because they run loaded at a slow speed while running one engine. Last night crossing Lake Superior running on dead calm seas I was getting over 2MPG at 9.3 knots. I hope the list doesn't mind my rambling. Let me know if I can give any other insights. Dennis Raedeke Wild Wind IV

Dennis Always interesting to read your posts - certainly not rambling. Roger Bingham France

Your last paragraph seems to indicate the benefit of variable pitch props as it relates to the load on a diesel marine engine. If you were buying a new catamaran would you order it with the latest variable pitch technology, or would you stay with fixed pitch prop and continue to use one engine while monitoring you EGT. >From a load stand point only; does running one engine at a time at slower speeds take care of "properly loading the engine" issue. I can now see that a EGT sensor and fuel flow meters makes a lot of since, and how it relates to the load issue, is this the only way to monitor load ? Thanks to everyone who has responded Jim Meader Broker/Owner RE/MAX Today Jim@rmtmail.com ________________________________ From: power-catamaran-bounces@lists.samurai.com on behalf of Dennis Raedeke Sent: Mon 6/15/2009 1:35 PM To: Power Catamaran List Subject: [PCW] Diesel load and related questions. It is ironic that I should just get home a few hours ago and check me email and the subject of CPP's comes up. For the last 12 days I have crossed Lake Superior and was fishing at Isle Royale National Park. During that time I used all the aspect of CPP's except one. The exception is the use of a CPP to be used as a transmission. Because the Hundested does not have the pitch range from full feather to full reverse, I can only change pitch from full feather to neutral pitch. I do have a regular transmission before the Hundested box. The reduction gear is 3/1. I noticed in the remarks by Michael Kasten that my type of CPP only goes to 300 HP. My engines are 330 HP. They did tell me I was on the limit. I think I only ran the engines all out twice, which produced 20 knots. A lot of interesting things happen when you want to go fast after running on one engine like I do most of the time. There are so many variables to look at. First the most important is the exhaust temp. The temp must be kept to a reasonable level. I have talked to a lot of people and no one has ever told me just how hot I could let the exhaust get. When I run at 16- 18 knots the exhaust gets to about 850. I noticed someone said something about 700. I first try to balance the engines so both engines are about the same RPM and the fuel burn is the same and exhaust temp equal. As I push the levers forward I watch the RPM, exhaust temp, hull speed and the fuel burn. If I try to accelerate to fast the exhaust temps climbs above what I consider too hot (850). Because of various conditions one engine always seems to carry more load and the exhaust temp climbs quicker. When this happens I have several choices. Slow that engine, reduce pitch or increase the other engine. With experience the process is not too bad. The interesting time is when I find myself in seas that are uncomfortable at my slow one engine speed. The ride is much better at 17 knots in rough seas until the seas get too big to go fast. When the waves react to each hull differently, balancing it all out can be fun. Even with the pitch gages the same it still seems to take balancing. I usually use the auto pilot while playing with all the controls. I know I cause my own problems because I run on one engine most of the time. If you ran with both engines most of the time the boat would operate just like fixed props. I brought up the fact that I was fishing because that is where CPP's shine. When trout fishing one needs to be able to troll from 1.2 knots and up. This could be done with a trolling valve, but the CPPs work to perfection. I feather one prop and then raise the RPM on that engine till the alternator is charging the way I want and adjust the pitch to the speed desired. In one of my postings I said I was going to try fixed pitch props. After thinking about all the hustle and the cost I never did. Now I don't need to as Mike on Chrysalis has given us the details. Wild Wind IV has traveled about 55,000 miles and has used over 40,000 gallons of diesel, which includes the genset and the diesel cabin heater. The engines have about 3600 hrs. If I ran two engines all the time, just think of the hrs. I believe my engines are in good shape because they run loaded at a slow speed while running one engine. Last night crossing Lake Superior running on dead calm seas I was getting over 2MPG at 9.3 knots. I hope the list doesn't mind my rambling. Let me know if I can give any other insights. Dennis Raedeke Wild Wind IV _______________________________________________ Power-Catamaran Mailing List -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.