Greenhorn question

[joemitchell]

Why on these small sailboats with small engines Raw water cooled ..??? And not a self contained sealed freshwater system ? And no one mentions " distilled water" ; ( 50/50 mix " coolant/ antifreze runs hotter than straight water ) Use 1 bottle of Redline Water Wetter . Runs Cooler. ie antifreze in So Cal Ocean Marina ?
ie 32 Ericson I am thinking of buying with Universal MB20B ; plenty of room etc for a couple of Radiators / with fans ..
And eliminate that constantly corrode-ing sytem ..... Lots less plumbing / thur-holes etc . Heat-Exchangers a guaranteed problem ..
PS I was trained as a motorcycle mechanic / auto mechanic than the last 10 years I was a tugboat engineer .

[four winds]

My guess, it would be difficult to bring in fresh cool air for the fans to force through the radiator, and provide an exit path for the heated air.

Placing the radiator in a more exposed location outside the engine room would bring up another set of difficulties and present an aesthetic dilemma as well.

[David M]

With a car radiator, you would still have to get the hot air out of the cabin or engine space.

[pillum]

Difficult to equate cars and motorcycles to boats in terms of mass airflow across air cooled engines or radiators. The slower the movement through the air the less air flow and hence less cooling, and boats travel relatively ssssssllllllooooowwwww. Also you would need to ensure that your air intakes are rated for heavy weather offshore use, using an IP-68 forced air cooling system would be cost prohibitive.

[NoTies]

NOISE

[noelex 77]

Welcome to the forum.

There are a few air / radiator cooled marine engines used in yachts, but it is not common.
It eliminates many problems with marine engines and when done well it can create a very reliable, if somewhat noisy, engine instalations .

However it is very difficult to retrofit an existing yacht. You need deck openings which are protected from spray to bring in cool air. The exhaust system needs to be changed to dry etc etc.

[GordMay]

Greetings and welcome aboard the CF, joemitchell.

[atoll]

much easyier is to fit a heat exchanger,and small electric central heating pump to circulate the cooling water

[joemitchell]

Someone mentioned how slow these boats move to the water . 1st most of these engines were originally " stationary engines" / tractors / industrial etc. Converted to marine use due primarily to their compactness. And then" Marined" with the technology at the time 30s/40s/ etc. ie very under sized oil systems ( thus Remote/ doubled filters/ and coolers); these important modifications will extend Engine Life 3-5+ times . And considerably COOL the engine ( esp cly head). My own Universal M320 has a 4 qt cap. I'd like to see at least 8 . Diesels at 21:1 compression ratio/ and old "oil rings" have a inherent BlowBy problem. IE the unburned gases BlowBy the Rings and you have diesel/carbon/etc. Extremely damaging. More oil/well filtered/cooled is necessary for any reasonable engine life. And critically important when stressing the engine.
Remote cold air induction with a decent air filter system;ie rewashable Foam.
Raw Water , corrode-ing system ; in my case I will Close Loop this system . 1st try (simply economically) vastly increase the water capacity(freshwater) in the block/cly head. ( run and check temps/ both water cooling systems and oil temp/pressure.) then add capacity to the original Raw Water corrode-ing system. Then as a safety backup add a small fan/ temp triggered .

[DeepFrz]

Let us know how it works out.

[GrowleyMonster]

I don't think radiators are allowed for cooling marine propulsion engines. There are air cooled diesels, but they have a reputation for being noisy. Sometimes this reputation is well earned, as with the Lister or Petter engines. There are cheap Chinese diesels that are air cooled. You don't have to go with an inboard heat exchanger... a keel cooler works just dandy. Lots of trawlers (actual trawling trawlers, not trawler style motor yachts) have them.

Raw water cooling was used for simplicity, compactness, and economy. In fresh or brackish water, it's not such a big deal anyway. Actually, come to think of it, my Atomic 4 which is OEM in my '76 built boat, is raw water cooled, and so far, so good. Of course, it could go any day. Maybe I will still be saying, "any day now", 20 years from now. It lives in brackish Lake Pontchartrain now, but spent much of its life in salt and ventures out into the salt now and then. Raw water cooling isn't a good thing, but it isn't always a terrible curse, either. YMMV.

[Kettlewell]

What makes you think your engine is running hot? In my experience, with a wide variety of marine engines, the OEM cooling systems are just fine. If it is currently raw water cooled I would try it out first before getting into elaborate mods to cure a problem that may not exist.

[ranger58sb]

Originally Posted by joemitchell

Why on these small sailboats with small engines Raw water cooled ..??? And not a self contained sealed freshwater system ? And no one mentions " distilled water" ; ( 50/50 mix " coolant/ antifreze runs hotter than straight water ) Use 1 bottle of Redline Water Wetter . Runs Cooler. ie antifreze in So Cal Ocean Marina ?
ie 32 Ericson I am thinking of buying with Universal MB20B ; plenty of room etc for a couple of Radiators / with fans ..
And eliminate that constantly corrode-ing sytem ..... Lots less plumbing / thur-holes etc . Heat-Exchangers a guaranteed problem ..
PS I was trained as a motorcycle mechanic / auto mechanic than the last 10 years I was a tugboat engineer .

I'd have thought you'd be seeing about as many many engines listed as fresh water cooled.

I'd guess you know this from your tugboat days, but for others, maybe...

These essentially have two parts to the cooling system: a closed coolant system (50/50 antifreeze/water) within the engine itself, AND a surrounding jacket through which raw water courses. The "freshwater" (coolant) at one point flows through a "heat exchanger" in several enclosed small tubes -- and raw water flows through there, too, around each of the coolant tubes. Raw water usually enters through a water pump, into the heat exchanger, aftercoolers and transmission oil coolers in larger implementations, and then out through the exhaust.

And of course that's not the same as raw water cooled...

-Chris

[Bash]

Originally Posted by joemitchell

Why on these small sailboats with small engines Raw water cooled ..???

In addition to the reasons mentioned so far, most of us run heat exchangers in our water heaters, using engine heat to generate hot water.