Inboard Exhaust Systems

Inboard Exhaust Systems

In the world of marine performance, you cannot underestimate the importance of inboard exhaust systems. Marine outboard exhaust systems get the exhaust out of the boat so you don't have to breathe it. Every inboard engine needs a way to get the exhaust out of the engine compartment. A simple boat exhaust blower can help clear away potential leaks, but you need something that can both get the exhaust out of the boat and make sure the water doesn't flow back into the engine.

What are the Basic Types of Exhaust Systems?

All marine exhausts do two things, by their very design: remove exhaust gasses and keep water out. Most boats feature a wet exhaust system, where water injects into the exhaust to moderate the temperature and noise levels. There are two basic approaches to follow to achieve these goals:

  • Above Water: As the name suggests, in this case the entire exhaust system operates above the waterline; it's easy to see what's going on but it can be noisy and they often run hotter than below water installations.
  • Below Water: Below water installations are quieter, but you don't have the same ability to look over the transom to see exactly what's happening. They do run cooler but also require a lift muffler and protection against damage from leaks.

What are the Main Constraints of Inboard Exhausts?

While the specifications of your engine and exhaust system may vary, there are certain requirements that every system should follow:

  • Restriction: Every engine works against a certain amount of back pressure from the exhaust. If you have too much back pressure you can lose power or worse damage the engine.
  • Size: The exhaust system has to fit in the space provided. You can move elements around, but if you cannot fit the exhaust risers marine engines in the compartment, it won't matter.
  • Gravity: Water always flows downwards, so when installing inboard marine mufflers on a wet exhaust system always make sure the water injection is on the downward side so leaks flow away from the engine.

Boat Exhaust and Maintenance

When looking for inboard engine parts always double check the exhaust system, as they have to withstand a lot of heat and stress. Despite the other differences, marine diesel engines use essentially the same exhausts as petrol engines.