First engine winterisation - would you critique my plan?

S

scrambledegg

Well-Known Member
Joined
2 Nov 2015
Messages
264
Location
Portsmouth
Visit site
Engine is a Sole Mini 33 on a sailboat, indirect freshwater cooled, direct prop shaft, going ashore in Chichester harbour.
I'm most concerned about flushing the raw water circuit, which this time needs to be completed with the boat still in the water. I know this has been covered before in the forum, but still I can imagine it going wrong.
Firstly, is it worth doing this at all? More from the corrosion protection point of view.
The basic plan is to siphon, first water then antifreeze mix, from a bucket with a length of hose into the raw water filter that is part of the sea cock fitting.
With engine running, close raw water inlet seacock, open filter cover, stuff primed siphon hose into the opening, allow maybe 5l fresh water to pass, switch other end of hose to a bucket of antifreeze mix, wait for mix to be seen coming out of exhaust, close filter cover, switch off engine.
What I'm mainly worrying about is ingress of air into the filter opening. If I have low flow from the siphon, or I'm late connecting it, could the circuit get air locked? Could the impeller get damaged?
What happens if the filter is opened without the engine running? Would the raw water in the cooling circuit empty itself into the bilges?
Excuse all these questions. One final one: anyone know where the engine anode on this engine is located? No mention of it in my manual.
Thanks.
 
Just before you shut down the engine, shut the seacock and most of the water will be pumped out. Remove the water pump impeller and the rest of the water will drain out. You can go through the process you described, but that is OTT. Once the raw water circuit is empty it cannot freeze!
 
If the manual does not mention an anode, or list replacement in the routine maintenance, its because there is not one. ( I've looked the manual so I know you are right)

Not needed in the engine itself because that is protected by the corrosion inhibitors in the antifreeze.

Some heat exchangers have one but others are made of materials that make one unnecessary.


You will only damage the impeller if you run it dry , so if you flush the raw water circuit as you suggest stop the engine without undue delay if there is no water going through it.
 
Last edited:
Tranona said:
Just before you shut down the engine, shut the seacock and most of the water will be pumped out. Remove the water pump impeller and the rest of the water will drain out. You can go through the process you described, but that is OTT. Once the raw water circuit is empty it cannot freeze!
Click to expand...

It is impossible for me completely to empty all water from my exhaust system. Think of water traps, silencers etc. The last thing I want is frost damage to any of these components, so it makes complete sense to me to run antifreeze through the raw water system immediately before stopping the engine. Any water remaining will be prevented from freezing. I do it after the boat is out of the water. I also take out the pump impeller to examine it, and if OK, refit it before launching.
 
Whether all the raw water will drain out of the heat exchanger or not will depend on the pipe work design and also perhaps on how much the engine is tilted aft – on my Beta it will not.

If you want to flush out with fresh water, I think with just 5 litres you might as well not bother.
Is there no chance of access to a water tap close to where the lift out takes place?

This photo below shows how I do it: Bypassing the intake and strainer I let the engine run on fresh water from the bucket for 10 - 15 minutes – bucket being fed by tap water hose.
Then the tap is closed and when the bucket is almost empty I pour in the 4 litres of water/antifreeze mix. When it is gone, the engine is cut. (Now is also a good time to change the engine oil, as it will be warm).
flushthrough.jpg
 
NormanS said:
It is impossible for me completely to empty all water from my exhaust system. Think of water traps, silencers etc. The last thing I want is frost damage to any of these components, so it makes complete sense to me to run antifreeze through the raw water system immediately before stopping the engine. Any water remaining will be prevented from freezing. I do it after the boat is out of the water. I also take out the pump impeller to examine it, and if OK, refit it before launching.
Click to expand...
On many boats, it's only a few joobly clips.
I like to get the exhaust dry if possible, to keep damp out of the boat and particularly the engine.
A wet vac is useful.

If you do leave water or coolant in the exhaust, you should disconnect it from the engine.

Running the engine ashore can be a bad idea unless in a good cradle, as wedges and props may rattle out.
 
BabaYaga
That does indeed look a much better way of doing it that the way I proposed - thank you.
I would need to find suitable diameter hose - just curious. do you know the diameter of that one in your picture?
 
When I run the engine to flush all the salt from the raw water side, and finally run some antifreeze through it (with the boat safely in her cradle), I use a system similar to BabaYaga's, except that my bucket, with a hose attached to its bottom, is hung over the outside at WL level, with the hose jammed up into the appropriate skin fitting. That saves doing any disconnecting of hoses to the pump.

I do the same in the Spring, just before launching, having changed the fuel filters, just to make sure that all is well.
 
Do not worry about impeller running dry they often do if used as bilge pump for a few seconds, the residual water in the casing will lubricate it sufficiently to allow you time to stop the engine.
 
scrambledegg said:
BabaYaga
That does indeed look a much better way of doing it that the way I proposed - thank you.
I would need to find suitable diameter hose - just curious. do you know the diameter of that one in your picture?
Click to expand...
Another way of doing it is to remove the input hose at the seacock place that in a bucket and fill the bucket with water from a hose while the engine is running.

Badly explained, but you will get the idea.
 
Several posters are talking about "frost damage" in relation to exhaust traps and suchlike but frost damage can only occur where the water freezes in a sealed confined space which is almost full of water and has no expansion space, like an undrained engine block sealed by the thermostat, such then when the ice forms it has nowhere to expand to and it cracks its container.

There is no chance of frost damage occuring in exhausts, water traps, drained blocks and pumps, and flexible hoses etc which is why Tranona advise that you forget about the antifreeze.

Richard
 
RichardS said:
There is no chance of frost damage occuring in exhausts, water traps, drained blocks and pumps, and flexible hoses etc which is why Tranona advise that you forget about the antifreeze.
Richard
Click to expand...

In my view the heat exchanger tube stack is the most vulnerable part. It is sufficient that one tiny pipe bursts and you will have a raw water/fresh water leak, difficult and expensive to repair.
Sure, water drains by itself when the impeller is removed, but how to be confident that every tube is empty? Or if not, that the freezing process is such that expanding water can escape?
A little anti-freeze in the heat exchanger is cheap insurance IMHO – if low temperatures are expected.
 
Last edited:
BabaYaga said:
In my view the heat exchanger tube stack is the most vulnerable part. It is sufficient that one tiny pipe bursts and you will have a raw water/fresh water leak, difficult and expensive to repair.
Sure, water drains by itself when the impeller is removed, but how to be confident that every tube is empty? Or if not, that the freezing process is such that expanding water can escape?
A little anti-freeze in the heat exchanger is cheap insurance IMHO – if low temperatures are expected.
Click to expand...

I am certain that all boats will have drain points below the level of the heat exchanger. Mine has two and if I were to remove the hose on the output side of the seawater pump then that would be a third. The H/E is open, at worst, to a large free air space on the output side through the exhaust elbow and down to the water trap. At best, it is open to the atmosphere through the exhaust.

IMHO there is no chance that the H/E will not drain down almost completely. Any residual seawater in there, whether in the tubes or in the output or input chambers, will never become pressurised through freezing.

Richard
 
RichardS said:
I am certain that all boats will have drain points below the level of the heat exchanger. Mine has two and if I were to remove the hose on the output side of the seawater pump then that would be a third. The H/E is open, at worst, to a large free air space on the output side through the exhaust elbow and down to the water trap. At best, it is open to the atmosphere through the exhaust.

IMHO there is no chance that the H/E will not drain down almost completely. Any residual seawater in there, whether in the tubes or in the output or input chambers, will never become pressurised through freezing.

Richard
Click to expand...

I presume you are aware of the other main benefit of using antifreeze, namely it's ability to prevent corrosion.
For all the time it takes to introduce some antifreeze into the raw water side, I and many others will continue to do so. The climate where my boat winters is quite cold, and if I can prevent the chance of freezing in the system, however slight in your eyes, and at the same time help to prevent ongoing corrosion in the manifold and elbow etc, for the sake of 5 litres of antifreeze, I'll continue to do it.
 
RichardS said:
I am certain that all boats will have drain points below the level of the heat exchanger. Mine has two and if I were to remove the hose on the output side of the seawater pump then that would be a third. The H/E is open, at worst, to a large free air space on the output side through the exhaust elbow and down to the water trap. At best, it is open to the atmosphere through the exhaust.

IMHO there is no chance that the H/E will not drain down almost completely. Any residual seawater in there, whether in the tubes or in the output or input chambers, will never become pressurised through freezing.

Richard
Click to expand...

Well, my Beta engine has no drain points as such in the sea water circuit. I agree that if both the impeller AND the zinc anode are removed most of the water will drain out. But newer engines have the anode in an other position, so less likely.

Also, the level of drain points is irrelevant if the water has to run up hill to get there.

As I see it, an open ended metal pipe filled with water might very well burst, if it freezes by the ends before it freezes in the middle.

Finally, protecting the sea water circuit by filling with anti-freeze is what the engine manufacturers recommend, at least Beta does. See page 43:
http://betamarine.co.uk/wp-content/uploads/downloads/operators_manuals/1590-1025-HEKC-SOM-0714.pdf
 
VicS said:
What would be more to the point would be what Sole S.A suggest for winterising their Mini 33 and to post a link to its manual,
Click to expand...

Ah ha! good point .... cut to the chase. Here it is....
http://www.solediesel.com/portals/0/ftp/manuales/u_mi33_en.pdf

Two pertinent sections (6.4 pg 24 operating the engine in low temps and 6.6 pg 25 long inactivity in low temperatures) :-
Section 6.4 Operating the engine at low temperatures
(2) When the engine is to be stopped, close the sea watercock, open the sea-water filter cover and start the engine adding
a mixture of fresh water and 30% anti-freeze until the sea-water circuit is filled completely. Stop the engine and replace
the sea-water filter cover. Before starting the engine again, open the sea-water cock. Repeat this operation whenever
the engine is used at temperatures below ºC.

Section 6.6 Long Inactivity Instructions
(4) Close the sea-water cock. Connect a hose from the sea water pump to a open bucket. Put 30% anti-freeze mixture to
the bucket. Start the engine for a moment. So the sea water system will be filled with anti-freeze mixture. Stop the
engine.

Interesting they advise two slightly different methods. Can't see why they would.
 
scrambledegg said:
Ah ha! good point .... cut to the chase. Here it is....
http://www.solediesel.com/portals/0/ftp/manuales/u_mi33_en.pdf

Two pertinent sections (6.4 pg 24 operating the engine in low temps and 6.6 pg 25 long inactivity in low temperatures) :-
Section 6.4 Operating the engine at low temperatures
(2) When the engine is to be stopped, close the sea watercock, open the sea-water filter cover and start the engine adding
a mixture of fresh water and 30% anti-freeze until the sea-water circuit is filled completely. Stop the engine and replace
the sea-water filter cover. Before starting the engine again, open the sea-water cock. Repeat this operation whenever
the engine is used at temperatures below ºC.

Section 6.6 Long Inactivity Instructions
(4) Close the sea-water cock. Connect a hose from the sea water pump to a open bucket. Put 30% anti-freeze mixture to
the bucket. Start the engine for a moment. So the sea water system will be filled with anti-freeze mixture. Stop the
engine.

Interesting they advise two slightly different methods. Can't see why they would.
Click to expand...

Presumably these are two slightly different methods of achieving the same end. Is that a copy and paste, because it is strange that it doesn't define the °C. ?

Personally I don't like filling the entire raw water system, because I prefer to take the impeller out for the winter, to save the blades from being permanently bent, but I'm not going to argue with the manufacturer.
 
NormanS said:
Presumably these are two slightly different methods of achieving the same end. Is that a copy and paste, because it is strange that it doesn't define the °C. ?

Personally I don't like filling the entire raw water system, because I prefer to take the impeller out for the winter, to save the blades from being permanently bent, but I'm not going to argue with the manufacturer.
Click to expand...

The impeller can still be taken out. Parts of the system that don't drain will contain antifreeze. The rest will at least be wet with a solution containing corrosion inhibitors and you can pop a brand new impeller in in the spring!

scrambledegg said:
Ah ha! good point .... cut to the chase. Here it is....
http://www.solediesel.com/portals/0/ftp/manuales/u_mi33_en.pdf

Two pertinent sections (6.4 pg 24 operating the engine in low temps and 6.6 pg 25 long inactivity in low temperatures) :-
Click to expand...

Get on with it then . You are overthinking the job!
 
You must log in or register to reply here.

Share this page

Top