The Triton

Where in the World

Yellowed piping telltale sign exhaust is too hot

ADVERTISEMENT

By Mike Prado

Many times when we visit yachts at the marinas and shipyards, we see that the main engine and generator exhaust wet section’s piping and mufflers, which are typically fiberglass and painted or powder-coated white, have turned yellow.

This discoloration is due to the exhaust temperature being too hot for the fiberglass and paint. Some of the conditions that can cause this overheating are exhaust gas temperatures, mixer tank efficiency, exhaust system piping geometry and muffler design. 

Calculating the velocity of the exhaust gases, exhaust temperature and waterflow from the engine water pump or auxiliary pump is critical. The manufacturer of the engine supplies the specifications for the water pump flow rate. This flow rate, along with the exhaust gas temperature and volume, is used in the design of the mixer tank. Note that it should be considered that some of this water flow could be diverted for other components, such as transmissions or shaft cooling, reducing the flow rate for the exhaust system. 

Also important: If the time/distance from the point where the hot exhaust gases come in contact with the raw water from the mixer tanks is too short, gases are not properly cooled and cause hot spots, which is the reason for the discoloration. In some cases, this can be remediated by the addition of a spray nozzle to aide in the cooling. Calculations need to be made to ensure the additional spray nozzle does not negatively impact the initial cooling by the mixer tank. 

The geometry of the piping between the turbo and the hull outlet – including the diameters, angles of elbows, length, compensators, hoses, valves and other materials – needs to be properly calculated. The diameter for inlets and outlets of all components from the outlet of the turbo to the inlet of the mixer tank-diffuser, including the diameter and thickness of the mixer tank itself, must be designed properly.

The muffler internal design calculation should have a minimal restriction for the exhaust gases, and location consideration of the waterline for the yacht. Placement too far below the waterline will increase the back pressure to the engine and also increase engine room temperature.

Proper design, calculations, engineering, manufacturing, and use of quality materials according to the engine manufacturers specifications all play an important role in ensuring a well-performing exhaust system that can last for decades.

Mike Prado is vice president of business development with DeAngelo Marine Exhaust in Fort Lauderdale. Comments are welcome below.

Related Posts...
By Capt. Patrick “Doc” Connelly This question could be asked Read more...
By Maria Karlsson Since Jan. 1, the Tax Cuts and Read more...
By Capt. Jeff Werner There is no emergency aboard a Read more...
By Joe Johnson The main reason to do background checks Read more...
By Lisa Samuels As I grow wiser in my life Read more...

Share This Post

Leave a comment

Your email address will not be published. Required fields are marked *

Please answer the question below to leave a comment. * Time limit is exhausted. Please reload CAPTCHA.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Editor’s Picks

Surveyor, former yacht engineer Mark Webb dies

Surveyor, former yacht engineer Mark Webb dies

By Dorie Cox An engineer and a yacht surveyor, Mark Webb died after complications from triple by-pass heart surgery in Fort Lauderdale. …

200 celebrate at Triton Networking with Maritime Marine

200 celebrate at Triton Networking with Maritime Marine

About 200 people enjoyed a Polynesian-inspired Triton Networking event last night at Maritime Marine in Fort Lauderdale. The team and …

Special delivery: Laurel crew transport no-longer-salty dogs

Special delivery: Laurel crew transport no-longer-salty dogs

By Dorie Cox; Photos by Purser Stephanie Hodges and Second Stew Shani Davies Cleaned up and rested, 10 dogs from the Bahamas Humane …

Veteran captain Achim Fischer dies in car accident

Veteran captain Achim Fischer dies in car accident

By Dorie Cox Capt. Achim Fischer died in Antibes on Nov. 26 as a result of a car accident. He was 72. A veteran captain of 30 years, …