muffler crack?

[Capt.Jim]

Stu, what I suspect is, the mechanic used a silicone 9-deg elbow from the riser into the side inlet, thus the highly flexible ell being somewhat similar to a 'hump".  Nothing short of a nuclear explosion will hurt the glass-reinforced centek.

That muffler is 1-1/2" inlet and outlet -- as you know the exh hose is 1-5/8", so......... How s/he may have 'adapted' may be interesting to see.  If he really wanted to use a side inlet, he should have used 1500003, the 1-5/8" in/out model.   The replacement should have been a centek 1-5/8" top in/top out.

kk

quote author=Stu Jackson link=topic=9252.msg67995#msg67995 date=1481382338]

Today we put Centek 1500071..
Side in/Top Out model... which felt ok and my mechanic swore that it'll be OK for my boat.
He added a 90 degree elbow hose for my existing hose to meet the side inlet.
Also 90 was a hump hose kind of softy hose which he says will minimize the vibration if not eliminates it completely.

Jim, could you please post a photo?  Right here, too, not on your photo topic.   I am having a great deal of difficulty understanding the side inlet geometry from the riser with a hump hose as you described.  Thanks.

[/quote]

There ya go gentlemen! 

[Stu Jackson]

Thanks for the photo, Jim.  Looks greast.

Except...

For the past 25 or more years, we have been trying against all odds to hammer home the IMPORTANCE of using blue HUMP HOSE between the exhaust riser and the muffle inlet.  Regardless of what type of muffler.

The concept is to avoid transferring vibration from the riser to the inlet port.

Your boat, your choice.   

But ITWMB I'd remove that black vertical hose and replace it with hump hose.  Available from Catalina Direct.  Years ago we had a lot of trouble finding it.  Nowadays, not so much.  Your muffler will ast a lot longer.

That said, could you fill us in on more than just the specific model and more details about the install?  Like supports, etc.   It would make a great Tech Note article.  You could become an instant rock star!

Thanks and again, nice work.

[Capt.Jim]

Thanks for the photo, Jim.  Looks greast.

Except...

For the past 25 or more years, we have been trying against all odds to hammer home the IMPORTANCE of using blue HUMP HOSE between the exhaust riser and the muffle inlet.  Regardless of what type of muffler.

The concept is to avoid transferring vibration from the riser to the inlet port.

Your boat, your choice.   

But ITWMB I'd remove that black vertical hose and replace it with hump hose.  Available from Catalina Direct.  Years ago we had a lot of trouble finding it.  Nowadays, not so much.  Your muffler will ast a lot longer.

That said, could you fill us in on more than just the specific model and more details about the install?  Like supports, etc.   It would make a great Tech Note article.  You could become an instant rock star!

Thanks and again, nice work.

Thanks for the kind words Stu... I will check with the blue hump hose... Just to see if it's any difference than what we used.

One thing I would like to repeat again in case you missed it in my earlier post; that small 90 elbow hose is really soft and nothing like the upright black hard one. So, the idea we came up with our genius(!) engineering minds  was that the any vibration caused by the engine and relayed thru riser/hard upright  hose will be diminish when it hits the softer 90 elbow.
Also the upright portion of the 90 elbow absorbs most of the vibration and the remaining minuscule amount of vibration is mostly diminished where 90 elbow contacts the muffler.

When engine running I checked by touching that soft 90 elbow and I was feeling more vibration on my knees (because of the position I was in) than on my fingers.
But again I'll check on your advice.
Thanks,

[KWKloeber]

Stu

It looks like it may be an EPDM (possibly silicone) elbow -- pretty soft and flexible. The hump hose (with the hump) helps prevent transferring lateral movement.  I'd think this elbow would be about 80% as good at that, though using a silicone hose above the elbow would add that 20%.

Jim,

Why didn't the mechanic just use a top-in -- considering that you could drop the hose right in? 

Here's the hump hose in use in Paul's blog:
http://www.sailingeximius.com/2016/07/exhasted-part-ii.html

If you happen do any adjusting, flip one clamp on the outlet so the worm dives oppose one another.   Also, the AWAB or ABA style clamps are SO much better for marine use, it's worth their cost to replace with them if for any reason you  have your hands on a hose clamp.  There's sources for discounts so you can buy ahead and save them for use, so don't have to pay WM prices.

-ken

Thanks for the photo, Jim.  Looks greast.

Except...

For the past 25 or more years, we have been trying against all odds to hammer home the IMPORTANCE of using blue HUMP HOSE between the exhaust riser and the muffle inlet.  Regardless of what type of muffler.

The concept is to avoid transferring vibration from the riser to the inlet port.

Your boat, your choice.   

But ITWMB I'd remove that black vertical hose and replace it with hump hose.  Available from Catalina Direct.  Years ago we had a lot of trouble finding it.  Nowadays, not so much.  Your muffler will ast a lot longer.

That said, could you fill us in on more than just the specific model and more details about the install?  Like supports, etc.   It would make a great Tech Note article.  You could become an instant rock star!

Thanks and again, nice work.

[KWKloeber]

Oh, Jim -- one thing I forgot to mention is that you'll find the drain on the Centek muffler is a PITA compared to the Aqualift. 

There's no petcock, just a 1/4" hex flange head screw threaded into the base that you must fully remove -- be ultra careful to not tighten it too much or cross the threads.  I have talked to the Centek engineer trying to get them to upgrade the drain -- the reply was, basically, "Not in our lifetime."

ken

[Stu Jackson]

One thing I would like to repeat again in case you missed it in my earlier post; that small 90 elbow hose is really soft and nothing like the upright black hard one.

You mean this one?

Also 90 was a hump hose kind of softy hose which he says will minimize the vibration if not eliminates it completely.

Always get a chuckle out of those complex engineering terms and references.   

[Capt.Jim]

One thing I would like to repeat again in case you missed it in my earlier post; that small 90 elbow hose is really soft and nothing like the upright black hard one.

You mean this one?

Also 90 was a hump hose kind of softy hose which he says will minimize the vibration if not eliminates it completely.

Always get a chuckle out of those complex engineering terms and references.   

Hey, it's not easy to be an expert in explaining things! 

[Ron Hill]

Jim : Once you get the engine running in the water you'll have to watch your "Softy Hose" to make sure it holds up. 
You'll also find out if you new muffler has enough capacity to handle the flow back of raw water from the 17ft exhaust hose when the engine is shut down.

A few thoughts

[KWKloeber]

Ron, where's the high spill-over spot in the exhaust hose on the 34? On the 30 its below the coming in the cockpit locker -- I'd guess maybe 2/3 the way along the hose route (also about 17 feet.)

-ken

[Stu Jackson]

Ron, where's the high spill-over spot in the exhaust hose on the 34? On the 30 its below the coming in the cockpit locker -- I'd guess maybe 2/3 the way along the hose route (also about 17 feet.)

-ken

Pretty much the same.

[Ron Hill]

Ken : That's the problem - that "spill over point" all depends on the longitudinal pitch of the boat. 
The early 1986 C34 had no aft water tank!  100 ft of chain in the anchor locker on another boat!  Two anchors on another.

The C34 MK 1 exhaust hose runs up from the muffler, over the fuel tank just under the coming for the genoa winch and turns down about the engine instrument panel - I'd guess 3/4 of the 17ft length.

Again - it all depends on the pitch of the boat. 

[Stu Jackson]

Ron, where's the high spill-over spot in the exhaust hose on the 34? On the 30 its below the coming in the cockpit locker -- I'd guess maybe 2/3 the way along the hose route (also about 17 feet.)

-ken

Pretty much the same.

Photos here:  http://c34.org/bbs/index.php/topic,6760.msg45302.html#msg45302

Exhaust Hose with Pictures.

Highest in the port locker above the fuel tank after it runs up from the muffler, then runs aft high, then down to the transom exit.

[KWKloeber]

Ken : That's the problem - that "spill over point" all depends on the longitudinal pitch of the boat. 
The early 1986 C34 had no aft water tank!  100 ft of chain in the anchor locker on another boat!  Two anchors on another.

The C34 MK 1 exhaust hose runs up from the muffler, over the fuel tank just under the coming for the genoa winch and turns down about the engine instrument panel - I'd guess 3/4 of the 17ft length.

Again - it all depends on the pitch of the boat.

Ron,

That route is pretty much the same as the 30 (sans fuel tank) -- and heads south to mid-stern right about at the panel.

It 'seems' that it would be an improvement to turn the hose down, as soon as it hits the coming.  Therefore creating one, defined spill-over point, as forward as possible.  Then the pitch wouldn't much matter.  Not seeing what's in the way, could it run at a 45, with a 45 elbow if necessary at the exit?

Some 30s had a check valve in the sail locker.

ken

[Ron Hill]

Ken ; Nice idea, but don't think it will work on a MK1 C34, as the hose needs to stay high all thru the port side lazerette.

I only mentioned the capacity of the muffler - as I believe it is something to at least consider!!
 
I believe that that is why Gerry Douglas made such a large capacity Aqua Lift muffler.  However, I'm sure Gerry could have designed a smaller muffler at a lesser cost - which would have made Frank happier!

A thought

[KWKloeber]

but don't think it will work on a MK1 C34, as the hose needs to stay high all thru the port side lazerette.

OK, I'll bite.  Why?

I only mentioned the capacity of the muffler - as I believe it is something to at least consider!!
 
I believe that that is why Gerry Douglas made such a large capacity Aqua Lift muffler.  However, I'm sure Gerry could have designed a smaller muffler

Absolutely -- the tiny 8" dia muffler is plenty large enough for the 3-cyl diesel according to Centek's Engineer.  Mine is 8" and has been operating just fine for 20 years.  Not having the location to have a high loop right off the muffler is what drove the oversize AL. 

But I doubt a smaller would save much.  $2.00 in fiberglass -- at the time. -- it was probably mostly labor cost.

ken