Hi, I am looking to buy a catalina 38 soon and was wondering what the advantages/disadvantages to having a freshwater cooling system for your engine were.
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C38 Engine Cooling
Grant What year C38 are you thinking of? The C38s had M25 engines that were fresh water cooled. Maybe just the later years. Perhaps earlier C38 versions had raw water cooled, but which engine are you dealing with? Fresh water cooled is usually preferred for longevity reasons.
Grant What year C38 are you thinking of? The C38s had M25 engines that were fresh water cooled. Maybe just the later years. Perhaps earlier C38 versions had raw water cooled, but which engine are you dealing with? Fresh water cooled is usually preferred for longevity reasons.
C38 cooling
The early c38s had atomic 4s and later went to a universal 5424 or M30 (same engine different name)and later changed to four cyl diesel in the 90's. The diesels are fresh water cooled but I'm not sure about the atomic4
The early c38s had atomic 4s and later went to a universal 5424 or M30 (same engine different name)and later changed to four cyl diesel in the 90's. The diesels are fresh water cooled but I'm not sure about the atomic4
Freshwater
As far as I know, freshwater is preferred since it keeps saltwater out of your engine, hence less corrosion and fouling in the cooling passages. The only advantage that I can think of for raw water cooling is that it's a simpler system since it doesn't have a heat exchanger.
As far as I know, freshwater is preferred since it keeps saltwater out of your engine, hence less corrosion and fouling in the cooling passages. The only advantage that I can think of for raw water cooling is that it's a simpler system since it doesn't have a heat exchanger.
Re:C38 Engine Cooling
I was thinking of a 1980-ish c38. Most have had fresh water but a few have been re-powered with universals and some of those have raw water cooling. I was just weighing the advantages of freshwater vs. saltwater and my main worry was drawing precious fw from my tanks when crusing.
I was thinking of a 1980-ish c38. Most have had fresh water but a few have been re-powered with universals and some of those have raw water cooling. I was just weighing the advantages of freshwater vs. saltwater and my main worry was drawing precious fw from my tanks when crusing.
Freshwater cooling
Hi Grant - I wouldn't worry about losing any freshwater from your tanks... the cooling system in your engine will be independent of your freshwater supply; the freshwater mixed with coolant in your engine is recirculated. Best, Trevor
Hi Grant - I wouldn't worry about losing any freshwater from your tanks... the cooling system in your engine will be independent of your freshwater supply; the freshwater mixed with coolant in your engine is recirculated. Best, Trevor
C38 Engines, and all the rest of them........
Grant Trevor's right. You do NOT use water from your boats freshwater (drinking) tanks to cool a freshwater cooled engine. The basics are: Raw water cooled: seawater (whether salt or fresh) is directly drawn into the engine and its cooing passages (block) to cool it. Freshwater cooled: There is an internal reservoir of freshwater with "antifreeze" coolant, just like your car. There is also a heat exchanger. The raw water (outside the hull, either salt or fresh depending on where your boat is, and what it's floating on) is drawn in by a raw water pump. It circulates through the heat exchanger, and is then blown overboard, after going through the heat exchanger, where it dumps its heat to the recirculated freshwater which is like the stuff in your car's coolant system. Think of it this way: Car: outside air Boat: water your boat is sailing in Car: stuff inside your radiator Boat: stuff inside your radiator Simple. Stu
Grant Trevor's right. You do NOT use water from your boats freshwater (drinking) tanks to cool a freshwater cooled engine. The basics are: Raw water cooled: seawater (whether salt or fresh) is directly drawn into the engine and its cooing passages (block) to cool it. Freshwater cooled: There is an internal reservoir of freshwater with "antifreeze" coolant, just like your car. There is also a heat exchanger. The raw water (outside the hull, either salt or fresh depending on where your boat is, and what it's floating on) is drawn in by a raw water pump. It circulates through the heat exchanger, and is then blown overboard, after going through the heat exchanger, where it dumps its heat to the recirculated freshwater which is like the stuff in your car's coolant system. Think of it this way: Car: outside air Boat: water your boat is sailing in Car: stuff inside your radiator Boat: stuff inside your radiator Simple. Stu
Pro's & Con's
Raw water cooled engines tend to run much cooler than their fresh water cousins. This can cause some carbon fouling of the cylinders and exhaust system. It also means that you cannot get much heat into your domestic hot water heater if you are on the hook. As mentioned, the raw water engines will circulate sea water throughout the engine with the possibility of enhanced corrosion within the engine block. Fresh water cooled systems are more complex, with two pumps and a heat exchanger, need to monitor antifreeze levels but give you hot water for your shower. Both types of systems have been in use for many years and with proper maintenance will continue to give you years of service.
Raw water cooled engines tend to run much cooler than their fresh water cousins. This can cause some carbon fouling of the cylinders and exhaust system. It also means that you cannot get much heat into your domestic hot water heater if you are on the hook. As mentioned, the raw water engines will circulate sea water throughout the engine with the possibility of enhanced corrosion within the engine block. Fresh water cooled systems are more complex, with two pumps and a heat exchanger, need to monitor antifreeze levels but give you hot water for your shower. Both types of systems have been in use for many years and with proper maintenance will continue to give you years of service.
Re: raw water cooling
Controlling engine temperature can be a problem with raw water cooling. A friend with a raw water cooled Sea Ray 37 got stuck behind a slow moving barge on the ICW, engine temp started rising because the water pumps were turning just above idle speed, higher than normal but not high enough to be of concern. When he finally got to open water, he gave the boat a handfull of throttle. The sudden on rush of colder ocean water either cracked a head or blew a head gasket (can't remember which). May not be applicable in the power ranges sailboats work in, but food for thought.
Controlling engine temperature can be a problem with raw water cooling. A friend with a raw water cooled Sea Ray 37 got stuck behind a slow moving barge on the ICW, engine temp started rising because the water pumps were turning just above idle speed, higher than normal but not high enough to be of concern. When he finally got to open water, he gave the boat a handfull of throttle. The sudden on rush of colder ocean water either cracked a head or blew a head gasket (can't remember which). May not be applicable in the power ranges sailboats work in, but food for thought.
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