Raw water cooling system - lay up

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Pat/ catalina 36

There are two methods mentioned in my manual for laying up the raw water circuit for winter, the dry and the wet. I have always used the dry method which is just to remove all excess water from the system. In Lake Michigan (fresh water) I feel this is an acceptable way for lay up, plus it is easier, and less costly than running anti-freeze (wet method)through the system. I did this on my last boat for 8 years with no issues. Interested in other's viewpoints. Thanks.
 
T

Tim

I'm interested as well......

Hello all, I have an 89' H30 with a yanmar 2gm20f. I'm in fresh water as well and I am interested in the responses to the above question. In Don Casey's book he recommends removing the impeller if the wet method is used. Is this necessary? If the "dry" method is used what is the proceedure for draining the raw water circut for my engine. Thank you in advance, Tim
 
Mar 31, 2004
244
Catalina 380 T Holland
It only costs $2.50 to use the "Wet Method"

to winterize your engine as all you need to do is suck one gallon of the pink propylene glycol based RV antifreeze (perhaps even less, unless you're feeling rich, and then you can use two gallons) through your engine using the water intake hose. This displaces the raw water out through the waterlift muffler, and completely winterizes your system. Since you already have permanent antifreeze on the "Fresh Water" side of the cooling system, there is no need to do anything to this half of the system unless you want to change the antifreeze. Using the "Dry Method" will usually work unless you are not completely successful in draining all of the water, and then you could ens up with water collecting in a low spot, and possibly break the pump or the heat exchanger (the raw water doesn't go through the engine, so you won't crack the block) I've been using this wet method for the past 15 years (5 on a Cal 27 with raw water cooling, and the past 10 on Catalinas with fresh water cooling, and all n Holland, MI, where it gets a bit frosty in the winter) I have never felt the need to remove the water pump impeller after doing this, and haven't ever broken off any vanes on my water pump impellers. Steve Alchemist C-320
 
Mar 28, 2005
182
Oday 272 Baltimore
It gets pumped out and replaced with

"fresh" raw water from the through-hull intake.
 
S

Scott

I guess getting pumped out ...

Means it ends up in the lake unless you catch it as it leaves the exhaust port. I am not sure why you would bother to remove the impeller. If it fails next spring you can replace it then for just a few bucks. You carry spares, don't you? I'd rather open it up once if I need to rather than twice (once in the fall and once in the spring) just to be miserly. I've always used the dry method but I can see were the wet method has the benefit of being less work. I'll relate an expensive mistake I made on my ski boat ... I got into the bad habit of draining all the water in the fall and then reconnecting all hoses, clamps and plugs. IF all the water is drained, this shouldn't be a problem. What I didn't realize was that some sediment in the water clogged the drainage ports in the block and one spring I had a V-8 260 CI chevy block CRACKED on both sides. I had nobody to blame but myself. It was a total loss and I replaced an 8-year old engine with relatively low hours because there was nobody but myself to take responsibility. I've gotten into the habit of hiring the marina to winterize. I can monitor what they do, but they are responsible for anything that goes wrong.
 
Jun 4, 2004
844
Hunter 28.5 Tolchester, MD
-100 Degree Antifreeze

I have to disagree with Alchemist; the cheaper antifreeze isn't worth the risk though I do agreee that 1 gallon will winterize the strainer, engine, heat exchanger and waterlift muffler. The 'pink stuff' turns slusshee a lot sooner than you might expect. The antifreeze mixes with the 1/2 + gallon of water that is still in the system as it pumps thru, so you can figure on 100% in the strainer and impeller pump, 90% in the heat exchanger and maybe less in the waterlift muffler.
 
Sep 15, 2006
202
Oday 27 Nova Scotia
Keep it wet

There was a detailed post on another site (Marine Diesel Direct site) about winterizing engines & one post in particular contained a very well considered ( the author was, I think, ex-US Navy engineering ) response. It said, in effect, that it is bad practice to flush the engine and then leave it "dry", with nothing but air in the coolant passages. The preferred technique is to fill the coolant passages, both the raw and the FWC parts, with an anti-freeze containing rust inhibitors, and leave it "wet" untill spring. I don't remember all the chemistry, but cast iron apparently forms a black protective coating in the cooling passages when wet, and if the coolant is drained and the passages contain air, the black coating will turn red, indicating another form of oxide, which will allow the iron to deteriorate and form a scale and much deeper penetration of the rusting. So, for the small effort & cost involved, it seems the preferred method is to fill ALL the passages and leave them like that for the duration.
 

RAD

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Jun 3, 2004
2,330
Catalina 30 Bay Shore, N.Y.
BTW..

Were talking about non toxic antifreeze used for fresh water drinking systems not engine antifreeze which is toxic so draining your system in the spring into the water should be no problem,I guess you could hold a bucket in front of the exhaust and try to catch most of it. And I agree with S. Sauer cause for an extra 3.00 you can get the better antifreeze and just to be sure.
 
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