Designing a Marine Exhaust System

[coopec43]

I read a thread regarding problems with an exhaust system and in particular the anti siphon valve. When constructing my exhaust system I followed an expert who wrote an article for Seaborne Marine. I undertook a search of my hard drive and found the article but now I can't find the thread again!

My exhaust system works very well and has been commented on favorably by people who should know about these things. Here is the link to the article.

https://www.sbmar.com/articles/desig...Cbgu8USjeDHUzV

[GordMay]

I recall several relevant discussions, including:

“Wet Exhaust System Design Help” ➥ https://www.cruisersforum.com/forums...lp-259540.html

“Exhaust expertise please” ➥ https://www.cruisersforum.com/forums...se-253904.html

“ Exhaust System Diagram (New System)” ➥ https://www.cruisersforum.com/forums...tem-32604.html


See also:

“Exhaust System Fundamentals” ~ by Dave Gerr
➥ https://www.cruisersforum.com/galler...613&original=1

“Why use a water-injected “wet” exhaust system?”
➥ https://www.frenchmarine.com/marine_...ssemblies.aspx

“Everything you Need to Know About Marine Exhaust Systems”
➥ https://www.sbmar.com/featured-artic...xhaust-systems

[coopec43]

Originally Posted by GordMay

I recall several relevant discussions, including:

“Wet Exhaust System Design Help” ➥ https://www.cruisersforum.com/forums...lp-259540.html

“Exhaust expertise please” ➥ https://www.cruisersforum.com/forums...se-253904.html

“ Exhaust System Diagram (New System)” ➥ https://www.cruisersforum.com/forums...tem-32604.html


See also:

“Exhaust System Fundamentals” ~ by Dave Gerr
➥ https://www.cruisersforum.com/galler...613&original=1

“Why use a water-injected “wet” exhaust system?”
➥ https://www.frenchmarine.com/marine_...ssemblies.aspx

“Everything you Need to Know About Marine Exhaust Systems”
➥ https://www.sbmar.com/featured-artic...xhaust-systems

Yes, no doubt there would be many threads on "wet exhaust design/problems" because it is a problem area.

The last link you have given appears to be to the same article I have linked to.

The author's argument is that you shouldn't use "anti siphon valves". My personal view is that any "expert" who suggests using them is just plain wrong..... I would therefore argue with David Gerr (who wrote the first article you have linked to) about the use of "siphon breaks"

[mvweebles]

Originally Posted by coopec43

.... The author's argument is that you shouldn't use "anti siphon valves". My personal view is that any "expert" who suggests using them is just plain wrong..... I would therefore argue with David Gerr (who wrote the first article you have linked to) about the use of "siphon breaks"

Are you saying a siphon loop is wrong? Frankly, I found Tony Athens SBMAR article a bit difficult to follow so not sure.

Both Gerr and Northern Lights have siphon breaks where exhaust manifold is below waterline. I would note that Northern Lights is the #1 marine generator supplier on the planet and has been for a very long time, and they frequently consult with builders on proper installation.

https://www.northern-lights.com/medi...t_drown_me.pdf

[coopec43]

Originally Posted by mvweebles

Are you saying a siphon loop is wrong? Frankly, I found Tony Athens SBMAR article a bit difficult to follow so not sure.

Both Gerr and Northern Lights have siphon breaks where exhaust manifold is below waterline. I would note that Northern Lights is the #1 marine generator supplier on the planet and has been for a very long time, and they frequently consult with builders on proper installation.

https://www.northern-lights.com/medi...t_drown_me.pdf

What I meant was you shouldn't use a valve. Instead of a valve I have a tube to a through hull fitting which in my case is well ave the waterline.

"Marine anti-siphon valves can become stuck due to a few reasons, including debris, rust, or scale buildup.These valves are designed to prevent water from siphoning back into the engine or boat from the toilet or other sources, so proper maintenance is crucial to prevent them from failing"

38mm Vented Loop 316 Stainless Steel Anti Siphon Vent Loop Valve Replacement for

[mvweebles]

Originally Posted by coopec43

What I meant was you shouldn't use a valve. Instead of a valve I have a tube to a through hull fitting which in my case is well ave the waterline. [/IMG]

Ah....thanks for the clarification. That makes sense - I once owned a boat that had a diversion line off the vented loop that went out the side of the boat.

[NorthCoastJoe]

I agree with the top of the loop being vented over the side. I had one with a rubber valve in it that needed frequent cleaning. Replaced it with a line over the side end of problems.

[GordMay]

Originally Posted by mvweebles

...
Both Gerr and Northern Lights have siphon breaks where exhaust manifold is below waterline. I would note that Northern Lights is the #1 marine generator supplier on the planet and has been for a very long time, and they frequently consult with builders on proper installation.

https://www.northern-lights.com/medi...t_drown_me.pdf

“Please don’t drown me” ~ A NORTHERN LIGHTS TECHNICAL INFORMATION PAPER
This document provides information and guidelines for properly installing a wet exhaust system on a marine generator to prevent engine damage. Key points discussed include using a siphon break, sloping exhaust lines, locating the exhaust outlet above the waterline, and avoiding low spots in hoses where water can collect.
➥ https://www.northern-lights.com/medi...t_drown_me.pdf