Ozone wrote
There it is,
According to Jocks, an exhaust system is completely sealed.
Nothing gets in, Nothing gets out.

similar to his head

First an exhaust is a sealed system

it is.

that can't get water into it,

it can. from and only from the water injection point and from the ocean.

now
it's got a water injection system,

yup, which has to be higher than the waterline or it will flood when the engine
is not running and the seacock is open

and an end open to the sea.

yes, that is why the lift outlet hose from the water lift muffler is supposed
to be at least 12 inches, better yet 18 inches, above the exhaust thru-hull.

what word didn't you understand, oxxy?

Then you try and tell me that water can only get into the exhaust when
the boat is "seriously rocking for some time".
What is this "seriously rocking"?

that is rocking through an angle fore and aft to the point that water in the
exhaust thru-hull is tipped and rolled forward enough to rise above the high
point of the exhaust outlet hose coming from the water lift muffler. It is
also rocking enough times to fill the water lift muffler from reverse and then
fill the outlet hose to more or less its high point to push the water in the
water lift muffler back into the engine exhaust manifold and push the air in
any cylinder with an open exhaust valve past that cylinder's rings and then
fill the cylinder with water. On most boats with a properly installed exhaust
outlet hose this is not a problem as the boats are normally used. In some
special cases the installation does also need to prevent water ingress due to
rocking.

Got anything to do with being on an ocean?

not really, through rocking conditions sufficient to water ingress are more
likely on the ocean that fresh water, ocean water is not necessary.

What about the hot engine cooling and sucking water in?

Cheers

JAXAshby wrote:

Then you try and tell me that water can only get into the exhaust when
the boat is "seriously rocking for some time".
What is this "seriously rocking"?


that is rocking through an angle fore and aft to the point that water in the
exhaust thru-hull is tipped and rolled forward enough to rise above the high
point of the exhaust outlet hose coming from the water lift muffler. It is
also rocking enough times to fill the water lift muffler from reverse and then
fill the outlet hose to more or less its high point to push the water in the
water lift muffler back into the engine exhaust manifold and push the air in
any cylinder with an open exhaust valve past that cylinder's rings and then
fill the cylinder with water. On most boats with a properly installed exhaust
outlet hose this is not a problem as the boats are normally used. In some
special cases the installation does also need to prevent water ingress due to
rocking.


Got anything to do with being on an ocean?


not really, through rocking conditions sufficient to water ingress are more
likely on the ocean that fresh water, ocean water is not necessary.

only happens in the voodoo land of crackerboxes.

What about the hot engine cooling and sucking water in?

Cheers

JAXAshby wrote:

Then you try and tell me that water can only get into the exhaust when
the boat is "seriously rocking for some time".
What is this "seriously rocking"?


that is rocking through an angle fore and aft to the point that water in
the
exhaust thru-hull is tipped and rolled forward enough to rise above the
high
point of the exhaust outlet hose coming from the water lift muffler. It is
also rocking enough times to fill the water lift muffler from reverse and
then
fill the outlet hose to more or less its high point to push the water in
the
water lift muffler back into the engine exhaust manifold and push the air
in
any cylinder with an open exhaust valve past that cylinder's rings and then
fill the cylinder with water. On most boats with a properly installed
exhaust
outlet hose this is not a problem as the boats are normally used. In some
special cases the installation does also need to prevent water ingress due
to
rocking.


Got anything to do with being on an ocean?


not really, through rocking conditions sufficient to water ingress are more
likely on the ocean that fresh water, ocean water is not necessary.

JAXAshby wrote:
First an exhaust is a sealed system

???

If it's sealed, then how does exhaust get into and/or out of it? How
does water?

And how come you never answered my question about whether the engine is
functioning as an air pump when it's cranking over but not starting?

Jaxxie, if you can't help my quest for technical knowledge, I guess I'll
have to ask Navvie...

DSK

oxxy, bring something of value to the discussion or go back to your sandbox.

First an exhaust is a sealed system

it is.

OK, is that good?

that can't get water into it,

it can. from and only from the water injection point and from the ocean.

Oh OK, so that's not goo right?
After all something that's sealed shouldn't leak eh?

now
it's got a water injection system,

yup, which has to be higher than the waterline or it will flood when the
engine
is not running and the seacock is open

OK, we covered taht, the sealed exhaust system isn't sealed but open
at 2 points....3 actually but you'd need to know a little about
engines to understand that......then again is it 4 points if you count
the syphon break?


what word didn't you understand, oxxy?

I'm still a little stumped on a totally sealed exhaust which you're
worried about getting water through the manifold when it's got open
ends.
BTW Jocks, ever seen what happens when a boat partially fills because
of say a holing and settles about 12"?


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you.

First an exhaust is a sealed system

???

If it's sealed, then how does exhaust get into and/or out of it?

the term sealed was used in the context of water ingress. keep up with the
class, dougies, or be left behind.

JAXAshby wrote:
the term sealed was used in the context of water ingress. keep up with the
class, dougies, or be left behind.

But if it is sealed then how can water get into it?

Seems to me that a sealed exhaust system would not be able to siphon
water back in now matter how much the boat rocked...

DSK

The point is that it is never perfectly sealed. Piston engines work
because they run fast enough that gas leakage past the piston is not a
problem. A similar issue exists in turbo seal leakage in t-charged
marine engines. Then there's the water injection point ...

Cheers

DSK wrote:

JAXAshby wrote:

the term sealed was used in the context of water ingress. keep up
with the
class, dougies, or be left behind.


But if it is sealed then how can water get into it?

Seems to me that a sealed exhaust system would not be able to siphon
water back in now matter how much the boat rocked...

DSK