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12-01-2025, 04:03
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#1
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Registered User
Join Date: Sep 2021
Location: East Africa
Boat: Garcia Alu retractable keel 42
Posts: 295
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Move a wet exhaust baffle/muffler
I am considering making some changes to my wet exhaust system.
I need to move the Vetus wet exhaust muffler further back in the engine bay.
What complications would be involved in this? Is this basically doable without too many complications or is the muffler designed to be at a certain height etc?
The above photos shows the current setup. For various reasons I would like to move the Vetus wet muffler further aft into the rear of the engine bay.
It would involve fabricating a new S/S exhaust pipe and wet muffler mounting brackets.
Any reason why this is a "problem" or not doable?
My first wet exhaust to deal with so have no prior knowledge. Any insights gratefully received.
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12-01-2025, 04:40
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#2
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Registered User
Join Date: Sep 2021
Location: East Africa
Boat: Garcia Alu retractable keel 42
Posts: 295
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Re: Move a wet exhaust baffle/muffler
WOW - something just jumped out at me - looking at the photo in the post above I can see that the photo shows the shaft is not running straight !
My Aluminum boat builder doing the Aluminum hull repair work spotted this and did the correction work to fix it - the shaft was running 14mm out of true to Starboard.
Explains the new engine mount on the aft starboard engine mounting point while the two front engine mounts were rusty as could be - clearly not changed in many many years - yet the back 2 mounts were newish, with the Aft Starboard mount being very newish as stated. At the time I was puzzled by this but now it all makes sense - with the shaft running out by 14mm to Starboard no wonder they kept replacing that engine mount !
Now the bag full of old engine mounts I found stowed away deep in a locker makes sense. They kept changing out that aft starboard mount !
The Skeg had extensive work done on it to correct all this. So its good now, but that photo was taken at purchase time and I never saw the shaft being so far out of aligment. Its an old game for young players !!!
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The above photos shows the extensive welding and strengthening of the skeg - this included straightening the skeg from 14mm to Starbaord to 0 mm down the centerline.
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12-01-2025, 06:34
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#4
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Registered User
Join Date: Sep 2021
Location: East Africa
Boat: Garcia Alu retractable keel 42
Posts: 295
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Re: Move a wet exhaust baffle/muffler
Thanks Gord !
Gord - quick question - is there anything you dont know :-) ?
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12-01-2025, 08:01
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#5
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Senior Cruiser

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 51,770
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Re: Move a wet exhaust baffle/muffler
Quote:
Originally Posted by Jim Jones
Thanks Gord !
Gord - quick question - is there anything you dont know :-) ?
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Yes - but,I don't know what.
According to the Rumsfeld matrix: I don’t know, what I don’t know.
There are infinite things, which any given person will not, and cannot, know about.
There are gaps in our knowledge; but gaps that we don’t know exist.
Quote:
Originally Posted by Rumsfeld
“There are known knowns; there are things we know we know.
We also know there are known unknowns; that is to say we know there are some things we do not know.
But there are also unknown unknowns - the ones we don't know we don't know...”
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BTW: “Boat Mechanical Systems Handbook” ~ by Dave Gerr is a great reference book.
I recommend that anyone interested, download and save it NOW, before it disappears.
➥ http://mololibrary.jblfmu.edu.ph/Boa...yDaveGerr).pdf
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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12-01-2025, 09:22
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#6
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Registered User
Join Date: Nov 2014
Posts: 1,676
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Re: Move a wet exhaust baffle/muffler
The main consideration is to maintain adequate drop
from the exhaust outlet to the entrance of the water
lift muffler. As the muffler moves aft it looks like it will rise, as the hull appears to rise in that area...
reducing the existing drop.
You might find it easier to use exhaust hose instead of stainless pipe. It's more flexible, won't corrode at the welds, and might not require support, which a longer
stainless pipe might require.
While you're at it, K&N makes a nice compact air filter which fits the D 2-55 engine. Angled neck to avoid the flywheel housing, etc.
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12-01-2025, 10:39
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#7
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Registered User
Join Date: Oct 2021
Posts: 685
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Re: Move a wet exhaust baffle/muffler
Another consideration in moving the muffler is the total volume of water that will fall into the muffler when the engine is shut down. For a longer connection on the engine side this will provide more water falling into the muffler. If the outlet portion that falls into the muffler (as opposed to overboard through the hull) is shortened by a similar amount then the total volume will be similar. If you accept that the original installer figured it out correctly the you are all good. If the combined length of exhaust falling into the muffler increases then you need to calculate the volumes involved and decide if you need a larger water trap.
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12-01-2025, 11:13
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#8
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Registered User
Join Date: Jan 2022
Boat: Contest 38s
Posts: 29
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Re: Move a wet exhaust baffle/muffler
BTW: “Boat Mechanical Systems Handbook” ~ by Dave Gerr is a great reference book.
I recommend that anyone interested, download and save it NOW, before it disappears.
➥ http://mololibrary.jblfmu.edu.ph/Boa...yDaveGerr).pdf[/QUOTE]
GordMay its just the contents - quick look up on google found the complete book - Thanks for the recommendation
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.mojaladja.com/upload/Profa/Brodski_mehanicki_prirucnik.pdf
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12-01-2025, 11:55
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#9
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Registered User
Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 21,171
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Re: Move a wet exhaust baffle/muffler
If the proportions and heights work well as is, try to keep them intact.
"if it works well, do not modify it"
I am saying move the muffler but try to retain the volumes and heights.
PS At times it makes sense to try and add a wet muffler drain - just in case one day you want to do a lot of work on the engine while the boat sits at the dock.
Flooding the muffler is a big NO NO NO.
b.
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15-01-2025, 11:42
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#10
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Senior Cruiser

Join Date: Nov 2014
Location: Kemah Tx
Boat: Gulfstar 51
Posts: 725
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Re: Move a wet exhaust baffle/muffler
i would not see a big issue with moving it aft as long as you keep the recommended drop from the engine to the muffler within bounds. I would definitely get rid of the SS pipe contraption on it right now and just use a straight downhill run of hardwall exhaust hose double clamped with T clamps on both ends- easy to do and simple. Putting in a drain on the muffler while you are doing it is super simple and worthwhile- can be as simple as a petcock threaded directly into the muffler- you may never need it but would be nice to have. As far as your shaft- some engines are purposely mounted at an angle - before you change consult others with your boat, it may have been done that way for a reason.
As far as volume of water going into the muffler, i dont think you are talking about a meaningful change there. by the way if you need fittings- elbows etc to fit the hi temp exhaust hose, CENTEC makes some that are relatively inexpensive and rated for the use. good luck
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15-01-2025, 17:13
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#11
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Registered User
Join Date: Jan 2023
Posts: 2,148
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Re: Move a wet exhaust baffle/muffler
I think I see the engine water intake hose connected directly to a hose fitting welded to the hull? With no valve? That's what my eyes tell me, but my brain says nobody could build a boat that way... If that is the way it actually is, adding a proper seacock would be my first priority for this boat. Like even before putting it in the water!
It is also not at all unsual in well designed boats to have the propshaft exit the boat at a small angle. The reason is so the prop shaft can be pulled out without hitting the rudder. Finding out that you have to lift the engine in order to pull the shaft can make a sailor say all kinds of bad words.
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16-01-2025, 01:22
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#12
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Senior Cruiser

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 51,770
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Re: Move a wet exhaust baffle/muffler
Quote:
Originally Posted by razamataz
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Thanks, razamataz:
➥ http://www.mojaladja.com/upload/Prof..._prirucnik.pdf
__________________
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"
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