Pro-Line Boats 33 Express Owner's Manual page 27

Eco-Sound Exhaust System
Idle Speed:
At start up and at idle speed the exhaust is accelerated through the low speed pipes at the port and
starboard thru hull fittings located above the water line and aft on the hull sides. This acceleration pushes the
exhaust out and away from the cockpit of the boat, dramatically reducing the smoke, smell and soot that would
otherwise collect around the cockpit.
Trolling Speed:
When you are fishing at trolling speeds, the exhaust accelerates out the low speed bypass
pipes. This keeps the exhaust smoke away from the cockpit, providing a more pleasant fishing and boating
experience.
Planing Speeds:
At planing speeds the chamber goes into a vacuum mode, vacuuming the exhaust gases from
the chamber. This action will lower the backpressure and provide more horsepower at the propeller for better
boat and engine performance. You will see the exhaust gases on the surface of the wake well behind the boat, and
again provides you with a more pleasant boating experience.
Backing Down:
The Eco-Sound System will dramatically increase back down speed while the low speed by-
pass pipes redirect choking fumes and smoke away from the aft deck and cockpit. The system becomes a real
fishing tool during back-down operations. The thrust of the exhaust creates additional lift as the vessel passes
over the exhaust that is forced downward. This thrust helps to counteract the downward pull of the propellers.
How the System Works
The exhaust system of the 33 Express Pro-Line developed by Eco Sound, Inc. represents the cutting edge of
current exhaust technology. The Exhaust & Performance System (EPS) 1000 is an exhaust exit point for diesel
and gas marine vessel applications. The patented design creates a partial vacuum that pulls the exhaust from the
system, redirecting it away from the influence of the station wagon effect. The system reduces backpressure
resulting in a more efficient, cleaner running engine. The EPS 1000 does this while dramatically quieting exhaust
noise.
Eco Sound's EPS 1000 is a chamber located at the stern of the vessel. The EPS chamber is actually a part of the
boat. A male mold insert is placed into the female hull mold (1) whereby a recess is formed (2) at the stern of the
boat on its centerline. An insert is installed completing the hull (3). This process provides optimal hull integrity.
At rest the EPS chamber is mostly full of water, at the same level as the waterline. When the engines are started
the exhaust exits through unobstructed 2" diameter marine exhaust hose (see drawing). There are no mufflers or
baffles in the EPS 1000. The baffles of a conventional muffler can cause unnecessary vibrations and noise.
Baffles also restrict the exhaust, inhibiting the engine's ability to breathe freely, resulting in unnecessary
backpressure. As the exhaust enters into the EPS chamber it decelerates as it passes from the small containment
area of the tubing to the large containment area of the EPS chamber. It is this deceleration process and the water
in the chamber that makes the system so quiet. Because the EPS chamber is mostly filled with water at low speed
and idle, the exhaust entering the chamber begins to fill this containment area. Inside the chamber there are low-
speed by-pass pipes, one for each engine. These by-pass pipes carry the exhaust from inside the chamber to the
port and starboard sides of the vessel by way of the thru-hull fittings located above the waterline (5). These by-
pass pipes are designed to accelerate the smoke, soot and fumes of the engine's exhaust four to five times faster
that the main engine exhaust. The result is that the exhaust is shot past the influence of the "station wagon"
effect. This keeps the fumes, smoke and soot away from the cockpit and transom, making the Pro-Line 33
Express cleaner after your day of boating and fishing.
Once the vessel reaches between five and six knots, the chamber empties of water. At the bottom of the chamber
there is a square opening (6). Forward of this opening is a wedge (7). As water passes over this wedge a venturi
is created, generating a great deal of negative pressure. This reduces the backpressure of the engine's exhaust
system creating a cleaner, more efficient burn in the engine cylinders while reducing smoke and soot. The result
is better fuel economy and higher boat speeds.
The Eco Sound EPS 1000 exhaust system in your 33 Express Pro-Line heightens the boating experience for you
and your guests on board.
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