Noisy exhaust problem solved with help from Vetus

Recently our senior marine engineer was called upon by City Cruises to solve an ongoing mystery.

Both their Rib vessels The Thunder and The Lightning were displaying some very puzzling traits. The vessels seemed very sluggish in their performance and the crew claimed that both boats could not seem to reach the speeds suggested by the manufacturer. 

French Marine performed extensive tests including back up pressure testing and numerous sea trials, our onboard investigations led us to the the conclusion that the problem lay with the exhaust flow. We removed the exhausts completely and tested the speed claims again. The vessels now ran at peak performance but one issue remained.
Once the silencers were removed the crew were concerned that the noise was of a totally unacceptable level for early and night time running of the vessels. 

The conclusion we reached was that from the point of origin, the HMI Exhausts that had been fitted were setup incorrectly.

Our solution for this problem was to fit a new Vetus lower back pressure silencer/muffler.

Mystery solved!