Running engine when ashore in a cradle?

[Pyramid]

For the winter, I have hauled out my Beneteau 36 cc and she now stands proud in a purpose built cradle. She has the Volovo Penta 2040 fresh water cooled engine .

I have started to winterise her engine and had thought to take water to the boat,run fresh water through the raw water system, flushing it of the salt and then run through fresh mixed with anti freeze. The fresh water cooling system has sufficient antifreeze and the oil good.

The question is should I run the engine whilst out of the water - engine mounts stress to hull etc.. I am of two minds. I have always done this before on my previous boat - a bilge keeler - Moody, but, well... as I say...I am in two minds, with my, new to me, pride and joy.

Is it necessary even? There are plenty that don't.

What's best for the boat? I know it's a production boat and all that, but I like it and want to keep it nice and not break it.

Si

 

[davidej]

Practically everyone does this - including me with a bene 361 which is very similar.

So why should you have a problem?

 

[robmcg]

I don't see you will have a problem. I was busy running up our engine in the cradle on Friday (even though the yard have a rule that you cant do this) - you need to winterise the engine, its standard practice.

 

[Deleted member 36384]

My yacht used to be stored on shores and I thought that the vibration would not be good for the shore integrity so I didn't but I would do so in a secure cradle. On the shores I would shove a hose with a bung into the raw water inlet and flush out the seawater that way. I then used a syphon from a 25 litre anti-freeze mix container on the coach roof via a hose taped to the raw water inlet hose. It took a few attempts but eventually I got the anti freeze around (exhaust soot ring round my mouth!). So there are alternatives.

 

[Poignard]

I was busy running up our engine in the cradle on Friday (even though the yard have a rule that you cant do this)

A job best left for a Sabbath morning!

 

[alahol2]

On the shores I would shove a hose with a bung into the raw water inlet and flush out the seawater that way. I then used a syphon from a 25 litre anti-freeze mix container on the coach roof via a hose taped to the raw water inlet hose. It took a few attempts but eventually I got the anti freeze around (exhaust soot ring round my mouth!). So there are alternatives.

If I tried this on my boat I would end up filling the exhaust pipe with water and that water would likely backfill into the exhaust valves and cylinders. You need to be very sure any swan-neck in the exhaust is below the level of your exhaust manifold.

 

[knuterikt]

For the winter, I have hauled out my Beneteau 36 cc and she now stands proud in a purpose built cradle. She has the Volovo Penta 2040 fresh water cooled engine .

I have started to winterise her engine and had thought to take water to the boat,run fresh water through the raw water system, flushing it of the salt and then run through fresh mixed with anti freeze. The fresh water cooling system has sufficient antifreeze and the oil good.

The question is should I run the engine whilst out of the water - engine mounts stress to hull etc.. I am of two minds. I have always done this before on my previous boat - a bilge keeler - Moody, but, well... as I say...I am in two minds, with my, new to me, pride and joy.

Can't see any problem running the engine while ashore in a cradle.
The only theoretical problem would be a small misalignment in the stuffing box - but you will not need to run the engine i gear?

Is it necessary even? There are plenty that don't.

Necessary - depends on how cold it will be during winter where you keep the boat.
I would not take the risk if it might get below zero under deck during winter...

What's best for the boat? I know it's a production boat and all that, but I like it and want to keep it nice and not break it.

Si

Getting some any freeze into the raw water system is a cheap insurance, you might get lucky without doing anything but again..

We use Propylene glycol based anti freeze for this - it's better for the environment http://en.wikipedia.org/wiki/Antifreeze#Propylene_glycol

 

[lw395]

I think it depends on the cradle.
I've seen a few vibrating horribly, wedges shaken out etc.
Won't be a problem on a proper fitted cradle.
Not sure about stuffing hose up the intake, you might fill the exhaust.
Just let the pump draw from a bucket.
I prefer to drain the seawater circuit than leave anti freeze in, but it's warmer down south of course.

 

[macd]

Just let the pump draw from a bucket.

+1, with the added precaution of removing the hose from the bucket a few seconds before switching off the engine.
When done, open the drain tap in the waterlock.

If I tried this on my boat I would end up filling the exhaust pipe with water and that water would likely backfill into the exhaust valves and cylinders. You need to be very sure any swan-neck in the exhaust is below the level of your exhaust manifold.

That's the danger of filling under pressure from a hose rather than letting the engine 'suck' from a bucket. Nonetheless I can't think of many installations in which the swan-neck would be below the level of the manifold. I suspect your concern may be based on an assumption that the exhaust holds a solid column of water, which is clearly impossible. Vetus' exhaust guidance assumes a max ratio of 3 parts exhaust gases to 1 part air (with a two-times safety margin, so volume calculations should be based on 2:1 gas to water).

 

[alahol2]

I suspect your concern may be based on an assumption that the exhaust holds a solid column of water, which is clearly impossible. Vetus' exhaust guidance assumes a max ratio of 3 parts exhaust gases to 1 part air (with a two-times safety margin, so volume calculations should be based on 2:1 gas to water).

Sorry, bad wording. What I should have said is that, if one is going to flush with pressurised water, one needs to be very sure any swan-neck in the exhaust is below the level of your exhaust manifold. I understand that most swan necks will be higher than the exhaust manifold, mine certainly is.

 

[Enya]

I don't see you will have a problem. I was busy running up our engine in the cradle on Friday (even though the yard have a rule that you cant do this) - you need to winterise the engine, its standard practice.

Do you really need to put antifreeze into the raw water side of a freshwater cooled engine? After all where is it going to rest? And isn't there plenty of expansion room if by chance the seawater freezes? In 6 years laid up ashore on the Solent I have never done this with no ill effects. Could we have some knowledgeable physics based answers please?

 

[NormanS]

Do you really need to put antifreeze into the raw water side of a freshwater cooled engine? After all where is it going to rest? And isn't there plenty of expansion room if by chance the seawater freezes? In 6 years laid up ashore on the Solent I have never done this with no ill effects. Could we have some knowledgeable physics based answers please?

My exhaust has a stainless steel mixing chamber down in the bottom of the boat, and another plastic(?) silencer (?), shortly before the outlet skin fitting, both of which hold a quantity of water. I wouldn't like either of them to freeze and burst, so I run antifreeze through the exhaust.

To the OP, if your boat is in a decent cradle, there is no danger in running the engine. I am amazed that any yards would have a rule against it.
On shores, I wouldn't even consider doing it.

 

[vyv_cox]

I suspect your concern may be based on an assumption that the exhaust holds a solid column of water, which is clearly impossible. Vetus' exhaust guidance assumes a max ratio of 3 parts exhaust gases to 1 part air (with a two-times safety margin, so volume calculations should be based on 2:1 gas to water).

When Owen (my son) worked for Sunsail some years ago they took delivery of a large number of newly designed boats from a well-known manufacturer. Before long these began to suffer engine failures. After lengthy investigation it was found that the exhaust trap capacity was insufficient for the volume of water in the hose, which was leading to water getting back into the engine. By the time this was discovered they had failed 40 engines!

 

[robmcg]

Do you really need to put antifreeze into the raw water side of a freshwater cooled engine? After all where is it going to rest? And isn't there plenty of expansion room if by chance the seawater freezes? In 6 years laid up ashore on the Solent I have never done this with no ill effects. Could we have some knowledgeable physics based answers please?

Don't know about the absolute physics but boat is lifted up a river where I presume salinity may be lower than at sea. Also do it to avoid freezing and splitting the silencer as Norman S suggests. It is but the work of a moment to quickly run some antifreeze through the raw water side and I can't see it having any ill effects.

 

[Enya]

Although my boat is on a substantial cradle and it would not take long to do the operation, I am now persuaded to see if I can drain the vetus traps as I am unpersuaded of the basic argument.

 

[CaptainBob]

In the winter of 2010-2011 in Whitby, some fishing boats, still in the water as they were still in use, had their heat exchangers explode overnight due to the seawater inside them freezing solid. Some boats in the yard we were in also had the ends pop off their exchangers.

We always flush through with anti-freeze.

Here's some icebergs on the river Esk at the time (which is salt water in this location):

http://www.yacht-forum.co.uk/viewtopic.php?t=331