How Do Water Lift Mufflers Work?

[Dockhead]

I have Halyard water lift mufflers on my boat (in fact, my very boat, which was the prototype for the M54, is what you see on the Halyard web site). One for generator and one for main engine.


I've never had water lift mufflers before. It's really nice in the case of the generator that there is no water splashing out of the exhaust, which is so annoying to others in the anchorage.


I am struggling however to understand how the water is removed from them. The exhaust goes downhill first to one can which is lower than the engine. Then back up to a second can which is above the engine. The cooling water is drained out of the HIGHER one, not the lower one. Why? And how does the water get up into the higher can, which is actually MUCH higher, more than a meter?

[sailormed]

I would think exhaust gas pressure pushes the water from the lower to the higher can. Exhaust gas can then continue unimpeded to the outside. The water from the higher can just gravity flows down to a through hull just above or below the water line.

[rslifkin]

Think of a standard water lift muffler as a cylindrical tank. Exhaust and water goes in the side about 1/3 of the way up. There's an outlet at the top with a dip tube to the bottom. So the exhaust pressure pushes exhaust and water down through the water in the bottom portion and up through the tube to exit. It does add some back pressure, but it provides good muffling.


In your setup, the second can is likely just a water separator to avoid the splashing.