Replacing Exhaust Pipes on Shamrock 20 Pilot House 1981

Gary S

Well-Known Member
Feb 4, 2010
1,706
167
Algonquin Illinois
That is what I ended up with but shorter runs of hose and I had a pair of rubber mufflers that looked crappy but did quiet it down a bit. The most sound dampening thing I did was rubber elbows on the exterior of the thru hulls.
Many years ago before he had his Shamrock dad had a 70's Ski Supreme with rubber mufflers from Salisbury. That was one of the quitest boats we have ever had,I think the rubber construction was the key. We called that boat the flexi flyer- when running the sides and deck would wiggle it was so thin.
 

Ship

Well-Known Member
Supporting Captain
Dec 15, 2008
12,114
329
Atlantic City, NJ area
Many years ago before he had his Shamrock dad had a 70's Ski Supreme with rubber mufflers from Salisbury. That was one of the quitest boats we have ever had,I think the rubber construction was the key. We called that boat the flexi flyer- when running the sides and deck would wiggle it was so thin.
That was the brand of the mufflers. Tried to get another pair for a friend and couldn't find any listings so they must have gone caput. They made mufflers on PT boats during the second world war.
 

Ship

Well-Known Member
Supporting Captain
Dec 15, 2008
12,114
329
Atlantic City, NJ area
I was looking for pictures of the mufflers on PT boats and was surprised to only see a couple with them mounted on the stern. Does anybody know if they mounted them internally as well?
 

Ron p Levin

Member
Mar 3, 2018
13
2
Bellingham, Washington
I replaced my exhaust with hose. One length on each side. I added 316 stainless muffler on each side. On an I pad there was an ap for db of noise. So my conclusion was that the exhaust noise at back of the boat was where noise came from but it was reduced. I think I remember buying one full length of hose from West and it was perfect for a 26 Stalker. Wire in the hose. I am very satisfied. I expect you would be too. Good Luck
 

Mistress

Moderator
Staff member
Supporting Captain
Jan 22, 2005
7,530
245
San Jose, CA
Both my 17 open and 26 Mack were all wired hose except for an elbow after the manifold. Short sections can be non-wired.

Just my observations on 2 shammies.

I'm not overly concerned with noise (or I wouldn't have a 12v Cummins).
 


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