N40475 Chapter 4 Silencers In some applications a reduction in noise levels from the exhaust would be desirable and to that extent, a silencer can be fitted. The exhaust system ejects the cooling water as well as silencing the engine’s combustion noise and removing the exhaust gases. The system must create minimal restriction to the flow of exhaust gases, known as back pressure, or the engine may be damaged. Figure 7 Figure 7 shows an engine sited well above the waterline (1), with a gradient steeper than 5 O to the back of the boat. The water will run naturally down the exhaust to the stern. To reduce noise a straightforward in-line silencer (2) should be used. Note:
The above is used in relation to 15kPa. Page 13