Re: Need some advice.[Ron]

One key to this discussion is the perceived power difference between a gasoline engine rated at 30 HP and diesel rated at 20 HP. I'm no engine expert (Joe Demers, are you out there?) but some vaguely-firing neurons inform me that at one time, I thought I knew that horsepower was rated differently for these two types of engine, and that a lower-rated diesel would have the same power output as a higher rated gasoline engine. Can anyone help out my CRS by providing chapter-and-verse on this one, or is this a total fabrication on my part? Alfred Poor 1973 T34C #288, "Jambalaya"

Horsepower is horsepower, no matter the source. However, the duty cycle of gas and diesel engines are different. Generally speaking, one can operate a diesel engine all day at very close to the engine's max rpm. This mode of operation generally cannot be sustained by a gas engine without abbreviating it's service life and burning LOTS of fuel. The Atomic 4 was marketed as a 30hp gas engine, which is was, - IF ! - it was operated at the max rpm of 3500. Most boat owners run the A4 at 2000 rpm, where the factory said it made 16hp WHEN NEW. Obviously, as the engine ages, it makes less than 16hp at this rpm. Also, most A4 transmissions were 1:1 ratio, which means the prop shaft ran at the same speed as the engine. This dictated that a small diameter prop must be installed, [ if one wished to take full advantage of the engine's 30hp ] which rotates at high speed. [ 12" or 13" diameter is common ] This setup is ideal for a lightweight planing powerboat, but much less than ideal for a displacement hull sailboat. An Atomic 4 replacement diesel engine will have a reduction ratio type transmission, usually 2:1. This means the prop shaft operates at 1/2 the speed of the engine, which allows for a large diameter, shallow pitched prop to be used. This is the correct and efficient way to drive a displacement hull. It allows the engine to reach it's max rpm, and develop it's maximum horsepower to drive the boat. This means the boat will maintain headway when encountering wind and waves. If you have an A4 with 1:1 transmission [ most A4s were sold this way ] in a displacement hull, a 16hp diesel engine will duplicate it's performance, while also being much lighter, and burning less than 1/2 the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that is the key to displacement hull performance ] will provide a marked improvement in performance when compared to an A4 with 1:1 transmission. Installing a 30hp diesel engine will result in a BIG power increase. Joe DeMers Sound Marine Diesel LLC www.soundmarinediesel.com ----- Original Message ----- From: Alfred Poor To: Ca… [at] yahoogroups.com Sent: Wednesday, December 19, 2007 8:34 AM Subject: [Cal_Boats] Re: Need some advice.[Ron] One key to this discussion is the perceived power difference between a gasoline engine rated at 30 HP and diesel rated at 20 HP. I'm no engine expert (Joe Demers, are you out there?) but some vaguely-firing neurons inform me that at one time, I thought I knew that horsepower was rated differently for these two types of engine, and that a lower-rated diesel would have the same power output as a higher rated gasoline engine. Can anyone help out my CRS by providing chapter-and-verse on this one, or is this a total fabrication on my part? Alfred Poor 1973 T34C #288, "Jambalaya" ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM

Joe DeMers wrote: > > > > If you have an A4 with 1:1 transmission [ most A4s were sold this way > ] in a displacement hull, a 16hp diesel engine will duplicate it's > performance, while also being much lighter, and burning less than 1/2 > the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that > is the key to displacement hull performance ] will provide a marked > improvement in performance when compared to an A4 with 1:1 > transmission. Installing a 30hp diesel engine will result in a BIG > power increase. > > OK, Joe, while you're answering questions.... I recall that diesels like running under load and that just idling is not their best function. Is there some point at which you have too much engine, that is to say, when your engine is just loafing too much for optimum longevity and service? Otherwise stated, if a 20 hp engine is suitable, is a 30 hp engine not only an unnecessary expenditure, but also less suited to the application? Chris Campbell

From: Chris Campbell To: Ca… [at] yahoogroups.com Sent: Wednesday, December 19, 2007 9:47 AM Subject: Re: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] Joe DeMers wrote: If you have an A4 with 1:1 transmission [ most A4s were sold this way ] in a displacement hull, a 16hp diesel engine will duplicate it's performance, while also being much lighter, and burning less than 1/2 the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that is the key to displacement hull performance ] will provide a marked improvement in performance when compared to an A4 with 1:1 transmission. Installing a 30hp diesel engine will result in a BIG power increase. OK, Joe, while you're answering questions.... I recall that diesels like running under load and that just idling is not their best function. ******* They function fine while idling, however, prolonged idling is injurious to any diesel or gas engine. It will shorten the engine's service life by diluting the lube oil with raw fuel, and will also cause carbon to accumulate throughout the exhaust system, and hinder the performance of the fuel injectors by restricting the correct atomization of fuel. Soon the engine will have black exhaust and become hard to start, as it has lowered compression, and therefore lowered horsepower. The only fix is engine rebuilding or replacement. Is there some point at which you have too much engine, that is to say, when your engine is just loafing too much for optimum longevity and service? **** Absolutely. The engine must be correctly matched to the application. Otherwise stated, if a 20 hp engine is suitable, is a 30 hp engine not only an unnecessary expenditure, but also less suited to the application? Chris Campbell ***** Precisely. I curerently have a customer with a 32' sloop, who is replacing an Atomic 4. He insists on installing the 28hp Beta Marine diesel engine, which is the wrong engine for this application. We suggest the 20hp engine, as it has PLENTY of power to drive the boat to hull speed, with a power reserve to fight wind and wave. A displacement hull boat requires only so much power to reach hull speed. A larger engine than is needed results in greater expense, less room in the engine space to maintain the engine, excess engine weight for the boat, and shortened engine life. Another big limiting factor is the prop diameter. If the boat can only acept a 12" or 13" prop, an oversized engine [ in this case, an engine over 20hp or so ] cannot transfer all it's power to the water. Why pay for horsepower that cannot be used? Joe DeMers Sound Marine Diesel LLC www.soundmarinediesel.com ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM

On behalf of the list and myself.... thanks Joe. My little 12 HP BMW thumper will drive my Cal 29 at hull speed with a 15" flex-o-fold prop, and I fill my 20 gallon tank once a year whether I need it or not. When this critter dies or gets to the point where I can't get a critical part, Joe gets a call for a new Beta 13.5 twin cylinder engine. If money were not an issue, I'd drop one in anyway just to experience the smoother and quieter motoring thing. Fortunately, the 29 is a sweet sailing boat and the motor is a secondary option most of the time. Regards, David Wilkie Owen Cal 2-29 "Mariposa" Santa Barbara, CA http://www.mariposasailing.com <http://www.mariposasailing.com/> _____ From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of Joe DeMers Sent: Wednesday, December 19, 2007 6:04 AM To: Ca… [at] yahoogroups.com Subject: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] Horsepower is horsepower, no matter the source. However, the duty cycle of gas and diesel engines are different. Generally speaking, one can operate a diesel engine all day at very close to the engine's max rpm. This mode of operation generally cannot be sustained by a gas engine without abbreviating it's service life and burning LOTS of fuel. The Atomic 4 was marketed as a 30hp gas engine, which is was, - IF ! - it was operated at the max rpm of 3500. Most boat owners run the A4 at 2000 rpm, where the factory said it made 16hp WHEN NEW. Obviously, as the engine ages, it makes less than 16hp at this rpm. Also, most A4 transmissions were 1:1 ratio, which means the prop shaft ran at the same speed as the engine. This dictated that a small diameter prop must be installed, [ if one wished to take full advantage of the engine's 30hp ] which rotates at high speed. [ 12" or 13" diameter is common ] This setup is ideal for a lightweight planing powerboat, but much less than ideal for a displacement hull sailboat. An Atomic 4 replacement diesel engine will have a reduction ratio type transmission, usually 2:1. This means the prop shaft operates at 1/2 the speed of the engine, which allows for a large diameter, shallow pitched prop to be used. This is the correct and efficient way to drive a displacement hull. It allows the engine to reach it's max rpm, and develop it's maximum horsepower to drive the boat. This means the boat will maintain headway when encountering wind and waves. If you have an A4 with 1:1 transmission [ most A4s were sold this way ] in a displacement hull, a 16hp diesel engine will duplicate it's performance, while also being much lighter, and burning less than 1/2 the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that is the key to displacement hull performance ] will provide a marked improvement in performance when compared to an A4 with 1:1 transmission. Installing a 30hp diesel engine will result in a BIG power increase. Joe DeMers Sound Marine Diesel LLC www.soundmarinedies <http://www.soundmarinediesel.com> el.com From: Alfred <mailto:ap… [at] bellatlantic.net> Poor To: Cal_Boats@yahoogrou <mailto:Ca… [at] yahoogroups.com> ps.com Sent: Wednesday, December 19, 2007 8:34 AM Subject: [Cal_Boats] Re: Need some advice.[Ron] One key to this discussion is the perceived power difference between a gasoline engine rated at 30 HP and diesel rated at 20 HP. I'm no engine expert (Joe Demers, are you out there?) but some vaguely-firing neurons inform me that at one time, I thought I knew that horsepower was rated differently for these two types of engine, and that a lower-rated diesel would have the same power output as a higher rated gasoline engine. Can anyone help out my CRS by providing chapter-and-verse on this one, or is this a total fabrication on my part? Alfred Poor 1973 T34C #288, "Jambalaya" _____ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM

I have a BMW D12 engine that was removed from a catboat I repowered with a Beta Marine 13.5hp engine. That BMW engine was actually built by Hatz in Germany. It is LOUD! The owner was very pleasantly surprised when he started the new engine for the first time, as he could actually hold a normal conversation in the cockpit! Joe DeMers Sound Marine Diesel LLC www.soundmarinediesel.com ----- Original Message ----- From: Wilkie To: Ca… [at] yahoogroups.com Sent: Wednesday, December 19, 2007 11:46 AM Subject: RE: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] On behalf of the list and myself.... thanks Joe. My little 12 HP BMW thumper will drive my Cal 29 at hull speed with a 15" flex-o-fold prop, and I fill my 20 gallon tank once a year whether I need it or not. When this critter dies or gets to the point where I can't get a critical part, Joe gets a call for a new Beta 13.5 twin cylinder engine. If money were not an issue, I'd drop one in anyway just to experience the smoother and quieter motoring thing. Fortunately, the 29 is a sweet sailing boat and the motor is a secondary option most of the time. Regards, David Wilkie Owen _________________ Cal 2-29 "Mariposa" Santa Barbara, CA http://www.mariposasailing.com ------------------------------------------------------------------------------ From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of Joe DeMers Sent: Wednesday, December 19, 2007 6:04 AM To: Ca… [at] yahoogroups.com Subject: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] Horsepower is horsepower, no matter the source. However, the duty cycle of gas and diesel engines are different. Generally speaking, one can operate a diesel engine all day at very close to the engine's max rpm. This mode of operation generally cannot be sustained by a gas engine without abbreviating it's service life and burning LOTS of fuel. The Atomic 4 was marketed as a 30hp gas engine, which is was, - IF ! - it was operated at the max rpm of 3500. Most boat owners run the A4 at 2000 rpm, where the factory said it made 16hp WHEN NEW. Obviously, as the engine ages, it makes less than 16hp at this rpm. Also, most A4 transmissions were 1:1 ratio, which means the prop shaft ran at the same speed as the engine. This dictated that a small diameter prop must be installed, [ if one wished to take full advantage of the engine's 30hp ] which rotates at high speed. [ 12" or 13" diameter is common ] This setup is ideal for a lightweight planing powerboat, but much less than ideal for a displacement hull sailboat. An Atomic 4 replacement diesel engine will have a reduction ratio type transmission, usually 2:1. This means the prop shaft operates at 1/2 the speed of the engine, which allows for a large diameter, shallow pitched prop to be used. This is the correct and efficient way to drive a displacement hull. It allows the engine to reach it's max rpm, and develop it's maximum horsepower to drive the boat. This means the boat will maintain headway when encountering wind and waves. If you have an A4 with 1:1 transmission [ most A4s were sold this way ] in a displacement hull, a 16hp diesel engine will duplicate it's performance, while also being much lighter, and burning less than 1/2 the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that is the key to displacement hull performance ] will provide a marked improvement in performance when compared to an A4 with 1:1 transmission. Installing a 30hp diesel engine will result in a BIG power increase. Joe DeMers Sound Marine Diesel LLC www.soundmarinediesel.com ----- Original Message ----- From: Alfred Poor To: Ca… [at] yahoogroups.com Sent: Wednesday, December 19, 2007 8:34 AM Subject: [Cal_Boats] Re: Need some advice.[Ron] One key to this discussion is the perceived power difference between a gasoline engine rated at 30 HP and diesel rated at 20 HP. I'm no engine expert (Joe Demers, are you out there?) but some vaguely-firing neurons inform me that at one time, I thought I knew that horsepower was rated differently for these two types of engine, and that a lower-rated diesel would have the same power output as a higher rated gasoline engine. Can anyone help out my CRS by providing chapter-and-verse on this one, or is this a total fabrication on my part? Alfred Poor 1973 T34C #288, "Jambalaya" ---------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM

LOL! Loud is right. That's why I call it the "African Queen." Wilkie _____ From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of Joe DeMers Sent: Wednesday, December 19, 2007 8:59 AM To: Ca… [at] yahoogroups.com Subject: [Cal_Boats] BMW D12 engine [ was Atomic 4 comparison to diesel ] I have a BMW D12 engine that was removed from a catboat I repowered with a Beta Marine 13.5hp engine. That BMW engine was actually built by Hatz in Germany. It is LOUD! The owner was very pleasantly surprised when he started the new engine for the first time, as he could actually hold a normal conversation in the cockpit! Joe DeMers Sound Marine Diesel LLC www.soundmarinedies <http://www.soundmarinediesel.com> el.com From: Wilkie <mailto:wi… [at] mariposasailing.com> To: Cal_Boats@yahoogrou <mailto:Ca… [at] yahoogroups.com> ps.com Sent: Wednesday, December 19, 2007 11:46 AM Subject: RE: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] On behalf of the list and myself.... thanks Joe. My little 12 HP BMW thumper will drive my Cal 29 at hull speed with a 15" flex-o-fold prop, and I fill my 20 gallon tank once a year whether I need it or not. When this critter dies or gets to the point where I can't get a critical part, Joe gets a call for a new Beta 13.5 twin cylinder engine. If money were not an issue, I'd drop one in anyway just to experience the smoother and quieter motoring thing. Fortunately, the 29 is a sweet sailing boat and the motor is a secondary option most of the time. Regards, David Wilkie Owen Cal 2-29 "Mariposa" Santa Barbara, CA http://www.mariposa <http://www.mariposasailing.com/> sailing.com _____ From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of Joe DeMers Sent: Wednesday, December 19, 2007 6:04 AM To: Ca… [at] yahoogroups.com Subject: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] Horsepower is horsepower, no matter the source. However, the duty cycle of gas and diesel engines are different. Generally speaking, one can operate a diesel engine all day at very close to the engine's max rpm. This mode of operation generally cannot be sustained by a gas engine without abbreviating it's service life and burning LOTS of fuel. The Atomic 4 was marketed as a 30hp gas engine, which is was, - IF ! - it was operated at the max rpm of 3500. Most boat owners run the A4 at 2000 rpm, where the factory said it made 16hp WHEN NEW. Obviously, as the engine ages, it makes less than 16hp at this rpm. Also, most A4 transmissions were 1:1 ratio, which means the prop shaft ran at the same speed as the engine. This dictated that a small diameter prop must be installed, [ if one wished to take full advantage of the engine's 30hp ] which rotates at high speed. [ 12" or 13" diameter is common ] This setup is ideal for a lightweight planing powerboat, but much less than ideal for a displacement hull sailboat. An Atomic 4 replacement diesel engine will have a reduction ratio type transmission, usually 2:1. This means the prop shaft operates at 1/2 the speed of the engine, which allows for a large diameter, shallow pitched prop to be used. This is the correct and efficient way to drive a displacement hull. It allows the engine to reach it's max rpm, and develop it's maximum horsepower to drive the boat. This means the boat will maintain headway when encountering wind and waves. If you have an A4 with 1:1 transmission [ most A4s were sold this way ] in a displacement hull, a 16hp diesel engine will duplicate it's performance, while also being much lighter, and burning less than 1/2 the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that is the key to displacement hull performance ] will provide a marked improvement in performance when compared to an A4 with 1:1 transmission. Installing a 30hp diesel engine will result in a BIG power increase. Joe DeMers Sound Marine Diesel LLC www.soundmarinedies <http://www.soundmarinediesel.com> el.com From: Alfred <mailto:ap… [at] bellatlantic.net> Poor To: Cal_Boats@yahoogrou <mailto:Ca… [at] yahoogroups.com> ps.com Sent: Wednesday, December 19, 2007 8:34 AM Subject: [Cal_Boats] Re: Need some advice.[Ron] One key to this discussion is the perceived power difference between a gasoline engine rated at 30 HP and diesel rated at 20 HP. I'm no engine expert (Joe Demers, are you out there?) but some vaguely-firing neurons inform me that at one time, I thought I knew that horsepower was rated differently for these two types of engine, and that a lower-rated diesel would have the same power output as a higher rated gasoline engine. Can anyone help out my CRS by providing chapter-and-verse on this one, or is this a total fabrication on my part? Alfred Poor 1973 T34C #288, "Jambalaya" _____ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM _____ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM

as I recall, the Beemer in David's boat was about as noisy as my original equipment 7hp two stroke inboard gas engine. Reggie To: Ca… [at] yahoogroups.comFrom: je… [at] mindspring.comDate: Wed, 19 Dec 2007 11:58:43 -0500Subject: [Cal_Boats] BMW D12 engine [ was Atomic 4 comparison to diesel ] I have a BMW D12 engine that was removed from a catboat I repowered with a Beta Marine 13.5hp engine. That BMW engine was actually built by Hatz in Germany. It is LOUD! The owner was very pleasantly surprised when he started the new engine for the first time, as he could actually hold a normal conversation in the cockpit! Joe DeMersSound Marine Diesel LLCwww.soundmarinediesel.com From: Wilkie To: Ca… [at] yahoogroups.com Sent: Wednesday, December 19, 2007 11:46 AM Subject: RE: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] On behalf of the list and myself.... thanks Joe. My little 12 HP BMW thumper will drive my Cal 29 at hull speed with a 15" flex-o-fold prop, and I fill my 20 gallon tank once a year whether I need it or not. When this critter dies or gets to the point where I can't get a critical part, Joe gets a call for a new Beta 13.5 twin cylinder engine. If money were not an issue, I'd drop one in anyway just to experience the smoother and quieter motoring thing. Fortunately, the 29 is a sweet sailing boat and the motor is a secondary option most of the time. Regards, David Wilkie Owen_________________Cal 2-29 "Mariposa"Santa Barbara, CAhttp://www.mariposasailing.com From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of Joe DeMersSent: Wednesday, December 19, 2007 6:04 AMTo: Ca… [at] yahoogroups.comSubject: [Cal_Boats] Atomic 4 comparison to diesel [ was Re: Need some advice.[Ron] Horsepower is horsepower, no matter the source. However, the duty cycle of gas and diesel engines are different. Generally speaking, one can operate a diesel engine all day at very close to the engine's max rpm. This mode of operation generally cannot be sustained by a gas engine without abbreviating it's service life and burning LOTS of fuel. The Atomic 4 was marketed as a 30hp gas engine, which is was, - IF ! - it was operated at the max rpm of 3500. Most boat owners run the A4 at 2000 rpm, where the factory said it made 16hp WHEN NEW. Obviously, as the engine ages, it makes less than 16hp at this rpm. Also, most A4 transmissions were 1:1 ratio, which means the prop shaft ran at the same speed as the engine. This dictated that a small diameter prop must be installed, [ if one wished to take full advantage of the engine's 30hp ] which rotates at high speed. [ 12" or 13" diameter is common ] This setup is ideal for a lightweight planing powerboat, but much less than ideal for a displacement hull sailboat. An Atomic 4 replacement diesel engine will have a reduction ratio type transmission, usually 2:1. This means the prop shaft operates at 1/2 the speed of the engine, which allows for a large diameter, shallow pitched prop to be used. This is the correct and efficient way to drive a displacement hull. It allows the engine to reach it's max rpm, and develop it's maximum horsepower to drive the boat. This means the boat will maintain headway when encountering wind and waves. If you have an A4 with 1:1 transmission [ most A4s were sold this way ] in a displacement hull, a 16hp diesel engine will duplicate it's performance, while also being much lighter, and burning less than 1/2 the fuel. A 20hp diesel with 2:1 gear and correctly sized prop [ that is the key to displacement hull performance ] will provide a marked improvement in performance when compared to an A4 with 1:1 transmission. Installing a 30hp diesel engine will result in a BIG power increase. Joe DeMersSound Marine Diesel LLCwww.soundmarinediesel.com From: Alfred Poor To: Ca… [at] yahoogroups.com Sent: Wednesday, December 19, 2007 8:34 AM Subject: [Cal_Boats] Re: Need some advice.[Ron] One key to this discussion is the perceived power difference between a gasoline engine rated at 30 HP and diesel rated at 20 HP. I’m no engine expert (Joe Demers, are you out there?) but some vaguely-firing neurons inform me that at one time, I thought I knew that horsepower was rated differently for these two types of engine, and that a lower-rated diesel would have the same power output as a higher rated gasoline engine. Can anyone help out my CRS by providing chapter-and-verse on this one, or is this a total fabrication on my part? Alfred Poor 1973 T34C #288, “Jambalaya” No virus found in this incoming message.Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM No virus found in this incoming message.Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.17.4/1187 - Release Date: 12/16/2007 11:36 AM