3 messages2016-11-15 22:13 UTCthrough 2016-11-16 21:09 UTC
Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
Claude Roberts2016-11-15 22:13 UTC
Wow Kris, thanks so much for taking the time to provide so much info. I will have to take a close look at the entire system relative to normal waterline as a start.
Sent via the Samsung GALAXY S® 5, an AT&T 4G LTE smartphone
From: "Kris Jensen cr… [at] att.net [Cal_Boats]" <Ca… [at] yahoogroups.com>
Date: 11/15/16 2:21 PM (GMT-06:00)
To: Ca… [at] yahoogroups.com, Joe DeMers <je… [at] mindspring.com>
Subject: Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
To provide an informed response, we really need to know what the entire system looks like from the Exhaust Manifold to the through-hull, and where all of that is in relation to the waterline (flat, heeled, and squatting)
On my Cruising 35 with the bass-ackwards engine, the previous owner redesigned the exhaust with a real belt and suspenders arrangement. Half of that occurs inside the engine space so is not visible from the lazzerette area. I could run the exhaust straight out the transom from the waterlock and theoretically have no trouble. Anyone familiar with boat exhausts would panic at the sight of that if they weren't aware of the arrangement on the front (back?) of the engine. Under the bridge-deck, there is an 18" dry riser with the injection elbow at the top. It's close to two feet above the water line at all times. Also the water injection tap for the dripless shaft seal is up there as well and provides a path for water to drain back to the waterline from the injection elbow.
If the OP has such an arrangement there is virtually no way that water will come back through the waterlock to the engine or rise to the level of the injection elbow. Adding a riser aft of the waterlock, while it can help provide peace of mind with respect to water backing up, can cause problems if it's higher than the injection port on the engine.
We all know that in an over-crank situation (no-start, bleeding injectors, etc) that the raw water pump is busy filling our exhaust system with water but the lack of actual exhaust is not pushing it out the transom effectively. If it fills up to the level of the injection elbow, it can flow back into the engine. However this cannot occur if everything in the exhaust after the injection elbow is lower. The excess water will just flow out the transom. Whatever point the water would drain (out the transom) if you're filling from the injection elbow is important. I'll call this the Spill-Over point. If I knew there was a foot of vertical drop between my injection elbow and the Spill-Over point then I'd crank to my hearts content and never worry about water filling up my engine. If there wasn't much distance or the Spill-Over was above the injection elbow, then you have to be very watchful of over-crank situations because the injection elbow can become the Spill-Over point.
Mine has an additional goose-neck riser after the waterlock and its spill-over is higher than the injection elbow. It goes up into the aft cockpit coaming so there is no possibility of a following sea pushing in. Theoretically the tap for the dripless shaft seal should drain any water to below the level of the tap in an over-crank situation but I don't know if the flow of the raw water pump during cranking can exceed the tap's ability to drain it away, so if I'm cranking for a while, I close the raw water valve until the engine fires.
If the OP's boat has sufficient risers, etc before the waterlock, then poking a fender under the exhaust hose just raises the spill-over point and does almost nothing to lessen the chances of a suction issue pulling water back from a submerged exhaust. Of course, raising the exhaust port on the transom can help but also raises the spill-over point so must be done mindfully.
There is virtually no possibility of water backing up when the engine is running. (think of walking Up the Down escalator) Also very low probability while you are sailing. It's the shutdown where folks can run into problems. A friends C & C 33 with an Atomic 4 had just a constantly sloping muffler and hose to the transom. Exhaust was generally above the waterline while motoring and sailing however he went through three head gaskets after he started Club Racing before he figured out what was going on. Typical day-sailing only used a few lines, minimal crew, etc. Club Racing meant there were multiple sheets, guys, twings, and 7 extra two hundred pound dudes on board. All of whom would end up standing in the vicinity of the cockpit coiling lines at the end of the day. After docking, the skipper would let the engine cool down for a bit, then shut it down. With 7 dudes plus him in the aft end of the boat, the exhaust was below the waterline and when the engine spun down, it would bounce off the compression and spin backwards just enough to hiccup a bit of water back into the engine. Paying attention to whether the exhaust was submerged when he shut it off solved that for him without changing his spill-over characteristics.
Exhaust port submerging while at speed is really fairly common and in most cases shouldn't cause a problem (as long as you are mindful of your exhaust characteristics and the ramifications of those) but as I said before, we'd really need to know what the whole arrangement is to give you usable opinions on yours.
I suppose what this "Book" points out is that exhaust system design (or re-design) requires careful thought, an understanding of basic physics, ability to comprehend and visualize spatial relationships, (what is this going to look like heeled 30 degrees to starboard? Now Port?), cause and effect analysis, (if I make a change to solve one problem, what new potential problem am I introducing?) tempered with the experience of dealing with the results of failures to get it right the first time.
So I guess what I'm saying in closing, is if you think it might not be right, ask somebody like Joe, or Tom, they'll know if it's an issue or not...
Kris
From: "Joe DeMers je… [at] mindspring.com [Cal_Boats]" <Ca… [at] yahoogroups.com>
To: Ca… [at] yahoogroups.com; Claude Roberts <uw… [at] yahoo.com>
Sent: Tuesday, November 15, 2016 6:33 AM
Subject: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
ABYC says this - The exhaust thru hull must not be submerged
during the normal operation of the boat.
When we repower old boats, we strive to update the exhaust
system to the latest standards. This is to ensure that raw water
can NEVER flow towards the engine, and enter the cylinders.
Obviously, this situation would lead to a VERY EXPENSIVE engine
repair.
We recently sold a new generator that was installed in a 40'
raceboat. The installer never bothered to investigate the correct
exhaust system design. 2 months later, the engine's cylinder was
discovered to be full of raw water. The boat owner is now faced
with a major engine rebuild, or engine replacement.
Joe DeMers - owner
Sound Marine Diesel LLC
SoundMarineDiesel.com
phone & fax (860) 666-2184
On 11/14/16 3:56 PM, Claude Roberts
uw… [at] yahoo.com [Cal_Boats] wrote:
Thanks for the response. I sail in the Gulf and ICW around
Port Aransas, TX. I have observed the same "squatting" under
sail only (she seems to approach hull speed much more quickly
than my former Catalina 30). Being on port tack lessens my
anxiety. No leaks evident around the exhaust port. My big
concern was salt water being siphoned back up the exhaust hose.
Sent via the
Samsung GALAXY S® 5, an AT&T 4G LTE smartphone
-------- Original message --------
From: "Jraxter jr… [at] triad.rr.com [Cal_Boats]"
<Ca… [at] yahoogroups.com>
Date: 11/14/16 10:02 AM (GMT-06:00)
To: Ca… [at] yahoogroups.com, Claude Roberts
<uw… [at] yahoo.com>
Subject: Re: [Cal_Boats] Cal 33 - exhaust submerging
Claude, welcome to the group!
Yes, this is typical of this
model.
The only negative I am aware of is
the possible leak at the exhaust fitting at the hull. Leakage
would drain into the engine bilge area.
Solution?
Slow down. Motoring at hull speed
burns more fuel.
Motor sail. With the main up
(reeled as prudent) the added drive force helps lessen the
squat. Heeling will lift that side on a port tack. Down wind
with the headsail will keep the bow up and prevent plowing in
to the back of waves. Sails will add a knot or two with less
engine thrust.
We changed to a three blade prop
several years ago. Better thrust in heavy seas, better
response in reverse, and I do not notice the squat when
motoring.
Where do you sail?
John Raxter
Cal 33
Oriental NC
On Nov 14, 2016, at 10:20 AM, Claude Roberts uw… [at] yahoo.com
[Cal_Boats] <Ca… [at] yahoogroups.com>
wrote:
New member of the group. Purchased a 1988 Cal 33 last
year (hull #788) and still getting to know her. I have
noticed that as she approaches hull speed, the stern
really "squats" as the bow climbs the bow wave and the
exhaust goes partially below the water. I have moved as
much weight as I can out of the port lazarette and aft
berth, but not easy since I live aboard.
My questions:
1) is this typical for Cal 33's and inconsequential or do
I need to continue trying to shift weight toward the bow?
2) what might be the adverse consequences of submerging
the exhaust relative to the heat exchanger, mixing elbow,
etc.?
Thanks in advance for your insight.
Claude
--
Joe DeMers - owner
Sound Marine Diesel LLC
SoundMarineDiesel.comphone & fax (860) 666-2184
Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
sk… [at] aol.com2016-11-15 23:00 UTC
We had a problem with occasional water coming in the exhaust outlet on the transom of our 1970 CAL 2/30. My engine guy installed a baffling muffler to prevent that from happening and we had no more water in the engine issues.
Stan
From: Claude Roberts uw… [at] yahoo.com [Cal_Boats] <Ca… [at] yahoogroups.com>
To: Kris Jensen cr… [at] att.net [Cal_Boats] <Ca… [at] yahoogroups.com>
Sent: Tue, Nov 15, 2016 5:14 pm
Subject: Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
Wow Kris, thanks so much for taking the time to provide so much info. I will have to take a close look at the entire system relative to normal waterline as a start.
Sent via the Samsung GALAXY S® 5, an AT&T 4G LTE smartphone
From: "Kris Jensen cr… [at] att.net [Cal_Boats]" <Ca… [at] yahoogroups.com>
Date: 11/15/16 2:21 PM (GMT-06:00)
To: Ca… [at] yahoogroups.com, Joe DeMers <je… [at] mindspring.com>
Subject: Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
To provide an informed response, we really need to know what the entire system looks like from the Exhaust Manifold to the through-hull, and where all of that is in relation to the waterline (flat, heeled, and squatting)
On my Cruising 35 with the bass-ackwards engine, the previous owner redesigned the exhaust with a real belt and suspenders arrangement. Half of that occurs inside the engine space so is not visible from the lazzerette area. I could run the exhaust straight out the transom from the waterlock and theoretically have no trouble. Anyone familiar with boat exhausts would panic at the sight of that if they weren't aware of the arrangement on the front (back?) of the engine. Under the bridge-deck, there is an 18" dry riser with the injection elbow at the top. It's close to two feet above the water line at all times. Also the water injection tap for the dripless shaft seal is up there as well and provides a path for water to drain back to the waterline from the injection elbow.
If the OP has such an arrangement there is virtually no way that water will come back through the waterlock to the engine or rise to the level of the injection elbow. Adding a riser aft of the waterlock, while it can help provide peace of mind with respect to water backing up, can cause problems if it's higher than the injection port on the engine.
We all know that in an over-crank situation (no-start, bleeding injectors, etc) that the raw water pump is busy filling our exhaust system with water but the lack of actual exhaust is not pushing it out the transom effectively. If it fills up to the level of the injection elbow, it can flow back into the engine. However this cannot occur if everything in the exhaust after the injection elbow is lower. The excess water will just flow out the transom. Whatever point the water would drain (out the transom) if you're filling from the injection elbow is important. I'll call this the Spill-Over point. If I knew there was a foot of vertical drop between my injection elbow and the Spill-Over point then I'd crank to my hearts content and never worry about water filling up my engine. If there wasn't much distance or the Spill-Over was above the injection elbow, then you have to be very watchful of over-crank situations because the injection elbow can become the Spill-Over point.
Mine has an additional goose-neck riser after the waterlock and its spill-over is higher than the injection elbow. It goes up into the aft cockpit coaming so there is no possibility of a following sea pushing in. Theoretically the tap for the dripless shaft seal should drain any water to below the level of the tap in an over-crank situation but I don't know if the flow of the raw water pump during cranking can exceed the tap's ability to drain it away, so if I'm cranking for a while, I close the raw water valve until the engine fires.
If the OP's boat has sufficient risers, etc before the waterlock, then poking a fender under the exhaust hose just raises the spill-over point and does almost nothing to lessen the chances of a suction issue pulling water back from a submerged exhaust. Of course, raising the exhaust port on the transom can help but also raises the spill-over point so must be done mindfully.
There is virtually no possibility of water backing up when the engine is running. (think of walking Up the Down escalator) Also very low probability while you are sailing. It's the shutdown where folks can run into problems. A friends C & C 33 with an Atomic 4 had just a constantly sloping muffler and hose to the transom. Exhaust was generally above the waterline while motoring and sailing however he went through three head gaskets after he started Club Racing before he figured out what was going on. Typical day-sailing only used a few lines, minimal crew, etc. Club Racing meant there were multiple sheets, guys, twings, and 7 extra two hundred pound dudes on board. All of whom would end up standing in the vicinity of the cockpit coiling lines at the end of the day. After docking, the skipper would let the engine cool down for a bit, then shut it down. With 7 dudes plus him in the aft end of the boat, the exhaust was below the waterline and when the engine spun down, it would bounce off the compression and spin backwards just enough to hiccup a bit of water back into the engine. Paying attention to whether the exhaust was submerged when he shut it off solved that for him without changing his spill-over characteristics.
Exhaust port submerging while at speed is really fairly common and in most cases shouldn't cause a problem (as long as you are mindful of your exhaust characteristics and the ramifications of those) but as I said before, we'd really need to know what the whole arrangement is to give you usable opinions on yours.
I suppose what this "Book" points out is that exhaust system design (or re-design) requires careful thought, an understanding of basic physics, ability to comprehend and visualize spatial relationships, (what is this going to look like heeled 30 degrees to starboard? Now Port?), cause and effect analysis, (if I make a change to solve one problem, what new potential problem am I introducing?) tempered with the experience of dealing with the results of failures to get it right the first time.
So I guess what I'm saying in closing, is if you think it might not be right, ask somebody like Joe, or Tom, they'll know if it's an issue or not...
Kris
From: "Joe DeMers je… [at] mindspring.com [Cal_Boats]" <Ca… [at] yahoogroups.com>
To: Ca… [at] yahoogroups.com; Claude Roberts <uw… [at] yahoo.com>
Sent: Tuesday, November 15, 2016 6:33 AM
Subject: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
ABYC says this - The exhaust thru hull must not be submerged during the normal operation of the boat.
When we repower old boats, we strive to update the exhaust system to the latest standards. This is to ensure that raw water can NEVER flow towards the engine, and enter the cylinders. Obviously, this situation would lead to a VERY EXPENSIVE engine repair.
We recently sold a new generator that was installed in a 40' raceboat. The installer never bothered to investigate the correct exhaust system design. 2 months later, the engine's cylinder was discovered to be full of raw water. The boat owner is now faced with a major engine rebuild, or engine replacement.
Joe DeMers - owner
Sound Marine Diesel LLC
SoundMarineDiesel.com phone & fax (860) 666-2184
On 11/14/16 3:56 PM, Claude Roberts uw… [at] yahoo.com [Cal_Boats] wrote:
Thanks for the response. I sail in the Gulf and ICW around Port Aransas, TX. I have observed the same "squatting" under sail only (she seems to approach hull speed much more quickly than my former Catalina 30). Being on port tack lessens my anxiety. No leaks evident around the exhaust port. My big concern was salt water being siphoned back up the exhaust hose.
Sent via the Samsung GALAXY S® 5, an AT&T 4G LTE smartphone
-------- Original message --------
From: "Jraxter jr… [at] triad.rr.com [Cal_Boats]" <Ca… [at] yahoogroups.com>
Date: 11/14/16 10:02 AM (GMT-06:00)
To: Ca… [at] yahoogroups.com, Claude Roberts <uw… [at] yahoo.com>
Subject: Re: [Cal_Boats] Cal 33 - exhaust submerging
Claude, welcome to the group!
Yes, this is typical of this model.
The only negative I am aware of is the possible leak at the exhaust fitting at the hull. Leakage would drain into the engine bilge area.
Solution?
Slow down. Motoring at hull speed burns more fuel.
Motor sail. With the main up (reeled as prudent) the added drive force helps lessen the squat. Heeling will lift that side on a port tack. Down wind with the headsail will keep the bow up and prevent plowing in to the back of waves. Sails will add a knot or two with less engine thrust.
We changed to a three blade prop several years ago. Better thrust in heavy seas, better response in reverse, and I do not notice the squat when motoring.
Where do you sail?
John Raxter
Cal 33
Oriental NC
On Nov 14, 2016, at 10:20 AM, Claude Roberts uw… [at] yahoo.com [Cal_Boats] <Ca… [at] yahoogroups.com> wrote:
New member of the group. Purchased a 1988 Cal 33 last year (hull #788) and still getting to know her. I have noticed that as she approaches hull speed, the stern really "squats" as the bow climbs the bow wave and the exhaust goes partially below the water. I have moved as much weight as I can out of the port lazarette and aft berth, but not easy since I live aboard.
My questions:
1) is this typical for Cal 33's and inconsequential or do I need to continue trying to shift weight toward the bow?
2) what might be the adverse consequences of submerging the exhaust relative to the heat exchanger, mixing elbow, etc.?
Thanks in advance for your insight.
Claude
--
Joe DeMers - owner
Sound Marine Diesel LLC
SoundMarineDiesel.comphone & fax (860) 666-2184
Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
Claude Roberts2016-11-16 21:09 UTC
Don,
That's reassuring - thanks!
Claude
--------------------------------------------
On Wed, 11/16/16, Donald C Dutton dn… [at] comcast.net [Cal_Boats] <Ca… [at] yahoogroups.com> wrote:
Subject: Re: [Cal_Boats] engine distruction - was Cal 33 - exhaust submerging
To: Ca… [at] yahoogroups.com, "NEWMAN" <d2… [at] gmail.com>
Cc: "Donald C Dutton" <dn… [at] comcast.net>
Date: Wednesday, November 16, 2016, 9:31 AM
I have sailed my Cal 33 (1986) through 36 foot seas
that broke over the boat at least six times. I have buried
the stern while motoring in D-waves that were 8 feet tall on
the Chesapeake and on Galveston Bay. I have never, not
once, had water enter the boat through the engine
exhaust.
Don Dutton1986 Cal 33-2, Quantum
EvolutionHayden
Island, Oregon
On Nov 15, 2016, at 5:04 PM,
NEWMAN d2… [at] gmail.com
[Cal_Boats] <Ca… [at] yahoogroups.com>
wrote:
Kris, TMI. I just meant I am not
changing my exhaust design. It works fine. The components
are not all original. I monitor all of my equipment and
maintain them. My 1949 caterpillar D2, 1955 D2, 1977 FJ40,
1973 Ford Bronco, 1939 Ford 9N, 1953 Farmall Super A, and
my 1986 Yanmar diesel. Leslie
On Tuesday, November 15, 2016,
Kris Jensen <cr… [at] att.net>
wrote:
I hear ya. I have enough to do
on my own boat without fixing everybody else's
too.
My engine is 43 years
old and has a newer head, injector pump and has had several
alternators, starters, and lift pumps. Everything in the
blocks is original. No one knows how many hours are on this
engine. It is on it's 6th or 7th exhaust system. It
is generally one the most abused, least robust portion of
the engine installation. Most everything else is made of
iron, steel, or aluminum and is bolted together. The
exhaust is rubber, plastic, and hose clamps...
I sincerely hope your
exhaust isn't 30 years old! I would have to predict
that your engine has COPD and would be running on borrowed
time if that were the case.
My last one made it 9
years (well actually it didn't, it was toast at about 7
but I didn't figure it out until 9) The previous owner
ran his first one for 8 years and had a failure due to
corrosion. After that, he changed everything from the
manifold back (with the exception of the waterlock) to the
transom every 5 years. When he pulled the set at 5 years
he said they were still very usable but certainly he would
never consider putting them back on. I ran his last set
for 9 and when I pulled it apart I discovered why the engine
was over heating. (in addition to the partly clogged heat
exchanger) the hard portion of the pipe below the exhaust
elbow was coked up so bad there was only about a 7/8's
inch hole to get the exhaust (and cooling water) out into
the 2 inch hose! At cruise RPM the engine was probably
using 10-15 hp just trying to stuff its own exhaust out
through that tiny hole. No problem at 1800 RPM, but try
running at 2400 and the temp just slowly crept up and up.
Now with a clean heat exchanger, and fresh exhaust, I made
several 5-7 hour runs at 2500 RPM with the temp gauge
sitting on 196 all day.
My 9 year old wire
reinforced hose had cracking in the outer surface and in
spots had broken through from the inside to the wire and
began to rust it. It was definitely time. Vetus
waterlock had about an inch of rust flakes and other
sediment in it. Nothing wrong with it otherwise.
Exhaust needs attention
just like the rest of the boat.
The point I'd like
to make with your "if it ain't broke don't fix
it" comment tho is, it's fairly likely that the guy
who designed/built these boats all those years ago was sharp
enough to build a safe and trouble free exhaust system.
However unless you are the original owner, you have no idea
how many fools have worked on it between then and now.
Again I'll refer you back to
Joe and Tom if you want to know how many and how often fools
do "professional" work on boats. ( i bet you
guys have some stories...)
That reminds me, do we have a
boat work "there I was..." thread? Those
stories should be captured for posterity.
Good Luck,
Kris
From: NEWMAN
<d2… [at] gmail.com>
To: Ca… [at] yahoogroups.com;
Kris Jensen <cr… [at] att.net>
Cc: Joe
DeMers <je… [at] mindspring.com>
Sent: Tuesday,
November 15, 2016 1:53 PM
Subject: Re:
[Cal_Boats] engine distruction - was Cal 33 - exhaust
submerging
All I know is my Cal 33 is 30 years old and the
engine functions flawlessly. I have motored and sailed many
hours without issue. I remember when I was very young an old
mechanic telling me something after I had mucked around with
something and screwed it up..."If it ain't broke,
don't fix it!". So mine stays like it is.
LesliePuffin
On Tue, Nov 15, 2016 at 3:21 PM,
Kris Jensen cr… [at] att.net [Cal_Boats] <Ca… [at] yahoogroups.com> wrote:
To provide an informed response,
we really need to know what the entire system looks like
from the Exhaust Manifold to the through-hull, and where all
of that is in relation to the waterline (flat, heeled, and
squatting)
On my Cruising 35 with
the bass-ackwards engine, the previous owner redesigned the
exhaust with a real belt and suspenders arrangement. Half
of that occurs inside the engine space so is not visible
from the lazzerette area. I could run the exhaust straight
out the transom from the waterlock and theoretically have no
trouble. Anyone familiar with boat exhausts would panic at
the sight of that if they weren't aware of the
arrangement on the front (back?) of the engine. Under the
bridge-deck, there is an 18" dry riser with the
injection elbow at the top. It's close to two feet
above the water line at all times. Also the water
injection tap for the dripless shaft seal is up there as
well and provides a path for water to drain back to the
waterline from the injection elbow.
If the OP has such an
arrangement there is virtually no way that water will come
back through the waterlock to the engine or rise to the
level of the injection elbow. Adding a riser aft of the
waterlock, while it can help provide peace of mind with
respect to water backing up, can cause problems if it's
higher than the injection port on the engine.
We all know that in an
over-crank situation (no-start, bleeding injectors, etc)
that the raw water pump is busy filling our exhaust system
with water but the lack of actual exhaust is not pushing it
out the transom effectively. If it fills up to the level
of the injection elbow, it can flow back into the engine.
However this cannot occur if everything in the exhaust after
the injection elbow is lower. The excess water will just
flow out the transom. Whatever point the water would drain
(out the transom) if you're filling from the injection
elbow is important. I'll call this the Spill-Over
point. If I knew there was a foot of vertical drop between
my injection elbow and the Spill-Over point then I'd
crank to my hearts content and never worry about water
filling up my engine. If there wasn't much distance or
the Spill-Over was above the injection elbow, then you have
to be very watchful of over-crank situations because the
injection elbow can become the Spill-Over point.
Mine has an additional
goose-neck riser after the waterlock and its spill-over is
higher than the injection elbow. It goes up into the aft
cockpit coaming so there is no possibility of a following
sea pushing in. Theoretically the tap for the dripless
shaft seal should drain any water to below the level of the
tap in an over-crank situation but I don't know if the
flow of the raw water pump during cranking can exceed the
tap's ability to drain it away, so if I'm cranking
for a while, I close the raw water valve until the engine
fires.
If the OP's boat
has sufficient risers, etc before the waterlock, then poking
a fender under the exhaust hose just raises the spill-over
point and does almost nothing to lessen the chances of a
suction issue pulling water back from a submerged exhaust.
Of course, raising the exhaust port on the transom can help
but also raises the spill-over point so must be done
mindfully.
There is virtually no
possibility of water backing up when the engine is
running. (think of walking Up the Down escalator) Also
very low probability while you are sailing. It's the
shutdown where folks can run into problems. A friends C
& C 33 with an Atomic 4 had just a constantly sloping
muffler and hose to the transom. Exhaust was generally
above the waterline while motoring and sailing however he
went through three head gaskets after he started Club Racing
before he figured out what was going on. Typical
day-sailing only used a few lines, minimal crew, etc. Club
Racing meant there were multiple sheets, guys, twings, and 7
extra two hundred pound dudes on board. All of whom would
end up standing in the vicinity of the cockpit coiling lines
at the end of the day. After docking, the skipper would
let the engine cool down for a bit, then shut it down.
With 7 dudes plus him in the aft end of the boat, the
exhaust was below the waterline and when the engine spun
down, it would bounce off the compression and spin backwards
just enough to hiccup a bit of water back into the engine.
Paying attention to whether the exhaust was submerged when
he shut it off solved that for him without changing his
spill-over characteristics.
Exhaust port submerging
while at speed is really fairly common and in most cases
shouldn't cause a problem (as long as you are mindful of
your exhaust characteristics and the ramifications of those)
but as I said before, we'd really need to know what the
whole arrangement is to give you usable opinions on
yours.
I suppose what this
"Book" points out is that exhaust system design
(or re-design) requires careful thought, an understanding of
basic physics, ability to comprehend and visualize spatial
relationships, (what is this going to look like heeled 30
degrees to starboard? Now Port?), cause and effect
analysis, (if I make a change to solve one problem, what new
potential problem am I introducing?) tempered with the
experience of dealing with the results of failures to get it
right the first time.
So I guess what I'm
saying in closing, is if you think it might not be right,
ask somebody like Joe, or Tom, they'll know if it's
an issue or not...
Kris
From: "Joe
DeMers je… [at] mindspring.com [Cal_Boats]"
<Ca… [at] yahoogroups.com>
To: Ca… [at] yahoogroups.com;
Claude Roberts <uw… [at] yahoo.com>
Sent: Tuesday,
November 15, 2016 6:33 AM
Subject: [Cal_Boats]
engine distruction - was Cal 33 - exhaust submerging
ABYC says this - The exhaust thru
hull must not be submerged during the normal operation of
the boat.When we
repower old boats, we strive to update the exhaust system to
the latest standards. This is to ensure that raw water can
NEVER flow towards the engine, and enter the cylinders.
Obviously, this situation would lead to a VERY EXPENSIVE
engine repair.
We recently sold a new
generator that was installed in a 40' raceboat. The
installer never bothered to investigate the correct exhaust
system design. 2 months later, the engine's cylinder was
discovered to be full of raw water. The boat owner is now
faced with a major engine rebuild, or engine
replacement.
Joe DeMers - ownerSound Marine Diesel LLCSoundMarineDiesel.com phone & fax (860)
666-2184
On 11/14/16 3:56 PM, Claude
Roberts uw… [at] yahoo.com [Cal_Boats]
wrote:
Thanks for the
response. I sail in the Gulf and ICW around Port Aransas,
TX. I have observed the same "squatting" under
sail only (she seems to approach hull speed much more
quickly than my former Catalina 30). Being on port tack
lessens my anxiety. No leaks evident around the exhaust
port. My big concern was salt water being siphoned back up
the exhaust hose.
Sent via the
Samsung GALAXY S® 5, an AT&T 4G LTE
smartphone
-------- Original message
--------
From:
"Jraxter jr… [at] triad.rr.com [Cal_Boats]" <Ca… [at] yahoogroups.com>
Date: 11/14/16 10:02
AM (GMT-06:00)
To: Ca… [at] yahoogroups.com,
Claude Roberts <uw… [at] yahoo.com>
Subject: Re:
[Cal_Boats] Cal 33 - exhaust submerging
Claude, welcome to the
group!
Yes, this is typical of this
model. The only
negative I am aware of is the possible leak at the exhaust
fitting at the hull. Leakage would drain into the engine
bilge area.
Solution? Slow down. Motoring at hull speed
burns more fuel.
Motor sail. With the main up
(reeled as prudent) the added drive force helps lessen the
squat. Heeling will lift that side on a port tack. Down wind
with the headsail will keep the bow up and prevent plowing
in to the back of waves. Sails will add a knot or two with
less engine thrust.
We changed to a three blade prop
several years ago. Better thrust in heavy seas, better
response in reverse, and I do not notice the squat when
motoring.
Where do you sail?
John RaxterCal 33Oriental NC
On Nov 14, 2016, at 10:20 AM,
Claude Roberts uw… [at] yahoo.com [Cal_Boats]
<Ca… [at] yahoogroups.com>
wrote:
New member of the group.
Purchased a 1988 Cal 33 last year (hull #788) and still
getting to know her. I have noticed that as she approaches
hull speed, the stern really "squats" as the bow
climbs the bow wave and the exhaust goes partially below the
water. I have moved as much weight as I can out of the port
lazarette and aft berth, but not easy since I live
aboard.
My
questions:
1) is
this typical for Cal 33's and inconsequential or do I
need to continue trying to shift weight toward the bow?
2) what might be the
adverse consequences of submerging the exhaust relative to
the heat exchanger, mixing elbow, etc.?
Thanks in advance for your
insight.
Claude
--
Joe DeMers - ownerSound Marine Diesel LLCSoundMarineDiesel.comphone & fax (860)
666-2184