Cruise from Heven & Hell

Apr 8, 2011
768
Hunter 40 Deale, MD
So I have a question: The (what looks like) fiberglass/heat shield fabric wrap that's on the exhaust pipe - is that something most folks have applied? My surveyor mentioned something about needing to do that (none of my exhaust plumbing is shielded in that way on my 2009 3YM30), and he mentioned in the survey that I should apply it. I wasn't really sure what he meant (first boat with an inboard), but seeing this I'm beginning to understand. Would appreciate being educated on the why and how of this.
 

Ward H

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Nov 7, 2011
3,645
Catalina 30 Mk II Barnegat, NJ
Wow Les, that’s 3 out of 3 cruises with excitement, adventure and challenge.
I bet that G&T was the best you ever tasted.
 
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Likes: jssailem
Jun 2, 2011
347
Hunter H33 Port Credit Harbour, ON.
So I have a question: The (what looks like) fiberglass/heat shield fabric wrap that's on the exhaust pipe - is that something most folks have applied? My surveyor mentioned something about needing to do that (none of my exhaust plumbing is shielded in that way on my 2009 3YM30), and he mentioned in the survey that I should apply it. I wasn't really sure what he meant (first boat with an inboard), but seeing this I'm beginning to understand. Would appreciate being educated on the why and how of this.
The shield wrap is normally a ceramic based material that can withstand very high heat. It is normally wrapped around rigid pipes that internally are exposed to raw exhaust. The wrap is to insulate the hot pipe from surrounding components. It is also used on some motor cycle exhausts.

On your 3 YM 30, I am pretty sure that your exhaust riser elbow is mounted directly to the exhaust manifold of the head. The water is injected into the downstream portion of the riser elbow. Half of the elbow has raw exhaust and the other half has cooled exhaust. Your flexible exhaust hose is most likely connected to the cooled side of the riser elbow. (this is how the 33 is configured so I am assuming that the 36 is the same) The cooled side of the exhaust does not need heat protection. Since the downstream side of the riser elbow is being cooled it also reduces the temperature of the raw exhaust side.

If it was necessary to have wrap protection I am sure that Yanmar would have had a protection boot over the elbow.
 
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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
So I have a question: The (what looks like) fiberglass/heat shield fabric wrap that's on the exhaust pipe - is that something most folks have applied? My surveyor mentioned something about needing to do that (none of my exhaust plumbing is shielded in that way on my 2009 3YM30), and he mentioned in the survey that I should apply it. I wasn't really sure what he meant (first boat with an inboard), but seeing this I'm beginning to understand. Would appreciate being educated on the why and how of this.
On the Catalina 36 it is absolutely required to prevent the wood from catching fire!!! It is a heat shield and would help keep temps down inside the boat. Look on Amazon for “header wrap kit” about $15. You want it between the manifold and hump hose.
 
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Likes: Ward H