MER Multi-layer SuperFlex sections last far longer than single wall sections.

This month we’re looking at the components we supply to build and maintain your commercial grade marine exhaust system. These systems are generally either “wet” or “dry”. A wet exhaust system is one that uses the spray of raw water to cool the exhaust stream before it flows out the back of the boat or even over the side.  A dry system, on the other hand, sends the exhaust gasses out of a vertical stack.  This month we’re discussing the components that make up a dry system.

First, there is the exhaust flex section that isolates and manages vibration and expansion of the system. Diesel engines develop an enormous amount of hot exhaust gas, and this causes expansion and lengthening of exhaust tubing. Similarly, every engine has a certain level of vibration. This results not only from rotating mass but also from the engine mounting arrangement. The sum of these forces is movement, a shoving contest between the engine and the exhaust system. Without a flex section, also called “wrinkle-belly”, the engine will lose every time.

Multi Layer SuperFlex

A 42-foot salmon seiner with a 400 horsepower engine can burn 20 gallons of fuel per hour. Roughly one million BTUs of heat is transferred by the engine’s exhaust system, and marine engines can have exhaust temperatures in excess of 1,200 degrees Fahrenheit (F). MER SuperFlex easily manages the movement in this extremely hot environment.  SuperFlex exhaust flex sections absorb expansion and contraction of the exhaust tubing and also ensure that engine vibration and movement “in the mounts” does not break the turbocharger exhaust housing. Flex sections come as either single or multi-layer tubing, however, multi-layer MER SuperFlex is the premium product for severe duty. Further, SuperFlex assemblies use a free-turning arrangement on one end, to facilitate convenient bolting. Convenient shipping brackets ensure the best fit-up and once the corresponding flanges are installed, the brackets are removed.

Adjustable Outlet

The marine engines MER sells, such as Isuzu engines from 300-600HP, Cummins, and John Deere engines throughout their range, including a turbocharger exhaust elbow that swivels a certain amount for ease of installation. Isuzu and Cummins goes a little further and supplies their single-layer exhaust flex section with certain new engine models.

Marmon System

Another MER product that complements our exhaust system offerings is the Marmon coupling. This exhaust coupling uses a compact V-band clamping system with fewer fasteners than exhaust flanges.  Unlike flanged/bolted exhaust connections, the V-band system makes insulating the system much simpler. In addition to this, there is just one-third the number of bolts.

Cowls Silencer Make Them Whisper


Then, there are the heavy duty exhaust silencers we handle: Compact Cowl silencers enable easy convenient mounting of the residential rated TS series. More important, however, we carefully size the silencer for each application. This results in the lowest noise level within the engine’s back pressure specifications. The Cowl MS series offers all of this, plus the convenience of optional, labor-saving mounting brackets.

MER Wrap System

When it is time to insulate your engine’s manifold or turbo, MER has custom fitted exhaust system blankets, sewn with high-temperature thread and custom made to protect your crew and prevent fire hazards.

A Word about MER Parts, our continual search for better heavy duty marine parts and components results in the addition of one or two carefully selected new products per year. The selection process requires high durability, fuel or energy savings, ease of maintenance and improved crew comfort and safety. So far this year we’ve added LED lighting and SuperFlex to our product line.