Waterlift Muffler Installation

S/V Synergy

June 3-11, 2003

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Here are a few pictures showing the new water lift muffler we installed on Synergy, and the custom stainless steel bracket that was built to support it.  A water lift muffler is nothing more than a reservoir of water through which water and exhaust gases are passed to muffle and cool the exhaust from the engine.  Our particular engine uses a raw (sea) water cooling system.  

A principle feature of our exhaust system is a steel elbow which is attached to the exhaust manifold.  The elbow receives water from the cooling system and combines it with the hot exhaust gases exiting from the engine.  These gases are cooled and diverted, via a short piece of hose, to the water lift muffler.  

The water lift muffler, named after its function, holds a small amount of water in a reservoir, through which exhaust gases are passed.  The water muffles the sound and further cools the gases.  As pressure inside the muffler builds, excess water is forced out of the muffler and up an exhaust hose to the thru-hull fitting.  Viewing the exhaust pipe from outside the boat, one would notice spurts of water as the cycle is repeated over and over.  

This explains why sailors always look at their exhaust pipe after starting the engine - to ensure that water flow is unobstructed.  Lack of water would indicate a blockage and should prompt an immediate shut-down of the engine to prevent costly damage. 

View of the engine room on Synergy.  This is what one would see when the cockpit sole (floor)  is removed.  The old muffler was attached to the engine.  Because of the cylindrical shape of the replacement muffler, a custom bracket was required.  I selected the starboard side engine-room liner wall because it offered the most space and still provided access to the stuffing box.

Here is the result of much swearing, cussing and crying:  the beginnings of a custom bracket template.

I used cardboard and wire to form the template.  Once the final adjustments were made, the template was handed over to a metal shop and a permanent, stainless steel bracket was fashioned.

Here the new stainless steel bracket has been mounted with 5200 marine adhesive and four 1" SS screws.  Despite their length, the screws never penetrated the hull.

This is a view looking forward with the new exhaust elbow attached to the exhaust manifold.  Note the thinner water hose and the 1-7/8" exhaust hose leading to the muffler.

Close-up view of the exhaust hose attachment to the elbow.  Always double-clamped!

Close-up view of the elbow with a good view of the water hose joint.

Here I've removed the water hose to expose the nipple on the elbow.  The nipple was actually added by a local welder because the factory had shipped the wrong diameter.

Here is a view of the muffler bracket, looking aft.  You can see where the curved pieces touching the muffler were widened with two-inch strips to minimize chafe.

Great view of the bracket, looking aft and parallel with the liner wall.

Another view of the bracket.  This one shows a mark left by welder where he noted the angle of the welded joint.

This is one picture that I'm glad I took.  It had been a long day by the time I had installed the muffler, and the additional hour that it took to wrangle with the hoses didn't make it any easier.  Well, I finished the job and snapped the picture.  When I got home and downloaded the photos, I noticed that the muffler was installed backwards (note the large arrow on the sticker)!!!  Rest assured, it is now oriented correctly.

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