Can anyone out there give me some informed and real world (yeah, I
know this is a newsgroup but, hope springs eternal) insight as to how
vulnerable raw water cooled engines are to damage from freezing?

I just discovered that our insurance policy doesn’t have a "haul by"
clause and I’d like to sail here in Maine as late as I can. With the
cooling system filled with salt water and the water temperature not
yet fallen, I can’t imagine that my 20 HP Yanmar is going to crack
something the first few nights the temperature drops into the high 20’s.
I’d sure hate to be wrong though.

When should I start worrying?

If there was an unseasonably cold night forecast, I'd probably go down
and warm up the engine just before bed.

--

Roger Long

Roger Long wrote:
Can anyone out there give me some informed and real world (yeah, I
know this is a newsgroup but, hope springs eternal) insight as to how
vulnerable raw water cooled engines are to damage from freezing?

I just discovered that our insurance policy doesn’t have a "haul by"
clause and I’d like to sail here in Maine as late as I can. With the
cooling system filled with salt water and the water temperature not
yet fallen, I can’t imagine that my 20 HP Yanmar is going to crack
something the first few nights the temperature drops into the high 20’s.
I’d sure hate to be wrong though.

When should I start worrying?

If there was an unseasonably cold night forecast, I'd probably go down
and warm up the engine just before bed.

I can't answer your exact question, but the last winter we headed
south we got overtaken by a nasty cold spell that we didn't expect.
If the forecast was for 28 degrees or less we drained the part of the
water system that runs through the cockpit; we had to do this 7 times
that December. The first time was in Myrtle Beach on Thanksgiving Eve
and the water lines on the dock burst.

We didn't worry about the engines because the water temp was still
fairly warm (in the 50's?) and I figured that would keep the engine
compartments from getting cold enough to freeze salt water.

There must be some type of safe heater you could use - even a 100 watt
bulb would add enough heat to prevent a freeze on a marginal night.
And, how hard is it to drain the water, or perhaps suck a quart of the
pink stuff into the engine?

I may be way off but I thought that outboards and inboards were safer
than I/O becuase they water drains out of them when not in use and
can't you just remove a hose and hook it up differently and make your
system a closed system. Can anyone tell me if I am right or wrong?
Also, get out your marine catalog and see what they sell for this.

"richard" wrote in message
oups.com...
I may be way off but I thought that outboards and inboards were safer
than I/O becuase they water drains out of them when not in use and
can't you just remove a hose and hook it up differently and make your
system a closed system. Can anyone tell me if I am right or wrong?

Even if you switch over to "closed system" you will still have seawater in
the heat exchanger and in the exhaust system. Anti freeze in the closed
system will work but no way to protect the standing sea water in the
exhaust.

Steve
s/v Good Intentions

"Roger Long" wrote in message
...
Can anyone out there give me some informed and real world (yeah, I know
this is a newsgroup but, hope springs eternal) insight as to how
vulnerable raw water cooled engines are to damage from freezing?


My Volvo is designed for sea water cooling and each cylinder jacket,
manifold and the OEM "water lift muffler" has a drain cock. Seems like a lot
to remember each fall but these drain every drop of water from the block. To
prevent these cast iron surfaces from rusting over the winter, I have
three-way sea cock that allows me to pump anti freeze into the system. I
don't actually do this, here in PacNW, since the temp never get that cold in
my boat (heater) and I like to have the option to go out for you sail when
the winter weather is nice.

Check the location of your drain cocks on you Yanmar, see if they drain all
the lowest points.

I happen to have a small Volvo MD7A here with a cracked exhaust manifold
because this model didn't have a drain cock and it must have frozen the
standing water. Such a drain cock would have saved this nice little engine.

Now I'm rambling. Sorry.

Steve
s/v Good Intentions

Sorry but 'drying' a cast iron engine will greatly shorten the service
life. What happens is that the cast iron begins to form 'slab rust'
..... huge plateletts of ferric rust that propagates between the natural
'laps' of the casting. Cast iron, due to the way it cools when molded
is similar to an 'onion' ... and the ferric corrosion (usual severe
rust) will rapidly develop between the 'laps' and form ferric rust ,
develop extreme pressure between the natural 'laps' and begin to
destroy the casting. If you keep the engine 'wet' (using such things
as antifreeze with rust inhibiters0 this process is greatly retarded.
Cast iron is a good metal vs. sea water as the high operating
temperature produces 'ferrous' rust ... a blue/black oxide that
actually protects against ferric rust.

The moral of this story is dont 'air-dry' your engine by draining all
the water out ..... put in a mixture of water and antifreeze - and
this will keep the protective 'ferrous' layer intact. Otherwise,
expect to develop pin holes and leaks in short order.

hope this helps.

In article , Steve
wrote:

"Roger Long" wrote in message
...
Can anyone out there give me some informed and real world (yeah, I know
this is a newsgroup but, hope springs eternal) insight as to how
vulnerable raw water cooled engines are to damage from freezing?


My Volvo is designed for sea water cooling and each cylinder jacket,
manifold and the OEM "water lift muffler" has a drain cock. Seems like a lot
to remember each fall but these drain every drop of water from the block. To
prevent these cast iron surfaces from rusting over the winter, I have
three-way sea cock that allows me to pump anti freeze into the system. I
don't actually do this, here in PacNW, since the temp never get that cold in
my boat (heater) and I like to have the option to go out for you sail when
the winter weather is nice.

Check the location of your drain cocks on you Yanmar, see if they drain all
the lowest points.

I happen to have a small Volvo MD7A here with a cracked exhaust manifold
because this model didn't have a drain cock and it must have frozen the
standing water. Such a drain cock would have saved this nice little engine.

Now I'm rambling. Sorry.

Steve
s/v Good Intentions

I agree and don't drain my engine unless I plan to lay it up with
anti-freeze.

As I mentioned in my reply to Richard, I have provisions for pumping
anti-freeze into the cooling jacket, if I were in a colder climate or didn't
keep a heater going in the winter.

Steve
s/v Good Intentions


"Rich Hampel" wrote in message
...
Sorry but 'drying' a cast iron engine will greatly shorten the service
life. What happens is that the cast iron begins to form 'slab rust'
.... huge plateletts of ferric rust that propagates between the natural
'laps' of the casting. Cast iron, due to the way it cools when molded
is similar to an 'onion' ... and the ferric corrosion (usual severe
rust) will rapidly develop between the 'laps' and form ferric rust ,
develop extreme pressure between the natural 'laps' and begin to
destroy the casting. If you keep the engine 'wet' (using such things
as antifreeze with rust inhibiters0 this process is greatly retarded.
Cast iron is a good metal vs. sea water as the high operating
temperature produces 'ferrous' rust ... a blue/black oxide that
actually protects against ferric rust.

The moral of this story is dont 'air-dry' your engine by draining all
the water out ..... put in a mixture of water and antifreeze - and
this will keep the protective 'ferrous' layer intact. Otherwise,
expect to develop pin holes and leaks in short order.

hope this helps.

I used to have a raw water cooled engine, and used to winterize by
pumping antifreeze through it, and closing the cocks. Let the engine
run to temperature so you circulate the antifreeze. Inboards tend to
stay a little warmer since they are closer to the water, which tends to
retain temperature, and protected in some way from the elements. I
would doubt that the first night or two in high 20s will cause it to
crack, but why strain it? I'd plumb a second connection to the
raw-water intake so you can easily and quickly pump some antifreeze
through it, easily enough to do it every time you get back from a trip.
You may also consider a "block heater" type device--I used one in my
car, which did not have an integral one, in -40 degrees. That one was
magnetic, designed for lawn-mower sized equipment, but it worked well
enough: plugged it in, and it attached magnetically to the engine. I
don't know how well it would work against freezing, and I doubt that
you can find one that is appropriate for marine use, so take that for
what you paid for it.

mickey

Simple answer to that is to add valved tee connectionIn to the intake
line and drain cocks teed to a common. Just drain the raw to the
bilge, saving if antifreeze into a bucket. simply, suck the antifreeze
back in when shutting down.


article , Steve
wrote:

I agree and don't drain my engine unless I plan to lay it up with
anti-freeze.

As I mentioned in my reply to Richard, I have provisions for pumping
anti-freeze into the cooling jacket, if I were in a colder climate or didn't
keep a heater going in the winter.

Steve
s/v Good Intentions


"Rich Hampel" wrote in message
...
Sorry but 'drying' a cast iron engine will greatly shorten the service
life. What happens is that the cast iron begins to form 'slab rust'
.... huge plateletts of ferric rust that propagates between the natural
'laps' of the casting. Cast iron, due to the way it cools when molded
is similar to an 'onion' ... and the ferric corrosion (usual severe
rust) will rapidly develop between the 'laps' and form ferric rust ,
develop extreme pressure between the natural 'laps' and begin to
destroy the casting. If you keep the engine 'wet' (using such things
as antifreeze with rust inhibiters0 this process is greatly retarded.
Cast iron is a good metal vs. sea water as the high operating
temperature produces 'ferrous' rust ... a blue/black oxide that
actually protects against ferric rust.

The moral of this story is dont 'air-dry' your engine by draining all
the water out ..... put in a mixture of water and antifreeze - and
this will keep the protective 'ferrous' layer intact. Otherwise,
expect to develop pin holes and leaks in short order.

hope this helps.

Steve,
I'd be curious to see how cold it gets near the engine in a sailboat
sitting in Hood Canal in winter. I doubt the temperature of the salt water
gets below 40 F and if the boat is sitting in it, the boat should stay that
temp. Also seawater freezing temp is about 28.4 F .
I can't see a block freezing and breaking in those conditions,
Now if the boat is on the hard, different story.
Gordon

"Steve" wrote in message
...

"Roger Long" wrote in message
...
Can anyone out there give me some informed and real world (yeah, I know
this is a newsgroup but, hope springs eternal) insight as to how
vulnerable raw water cooled engines are to damage from freezing?


My Volvo is designed for sea water cooling and each cylinder jacket,
manifold and the OEM "water lift muffler" has a drain cock. Seems like a
lot
to remember each fall but these drain every drop of water from the block.
To
prevent these cast iron surfaces from rusting over the winter, I have
three-way sea cock that allows me to pump anti freeze into the system. I
don't actually do this, here in PacNW, since the temp never get that cold
in
my boat (heater) and I like to have the option to go out for you sail when
the winter weather is nice.

Check the location of your drain cocks on you Yanmar, see if they drain
all
the lowest points.

I happen to have a small Volvo MD7A here with a cracked exhaust manifold
because this model didn't have a drain cock and it must have frozen the
standing water. Such a drain cock would have saved this nice little
engine.

Now I'm rambling. Sorry.

Steve
s/v Good Intentions