Wet exhaust back flow prevention?
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Richard Cashore
- Posts: 8
- Joined: Feb 10th, '05, 19:51
- Location: Bridges Point 24
Wet exhaust back flow prevention?
I have a Westerbeke 12B Two With fresh water cooling. I'm refitting the exhaust system. I'd like an exhaust system that prevents water from backing up into the engine. What are the alternatives available? What other items should I be concerned about with the exhaust system?
You can put a flapper on the outboard end of the exhaust......if you can find one that fits. More importantly - loop the exhaust line up as high as possible, then down and out the transom.
On my boat the exhaust exits the waterlift muffler (Vetus), and follows the hull to the stern. It then rises ( about 22")to the underside of the rear deck, loops around and then down to the exhaust fitting on the transom. Be certain the exhaust is well supported and secured. The exhaust should exit the hull a few inches above the waterline.
________
Drug Test
On my boat the exhaust exits the waterlift muffler (Vetus), and follows the hull to the stern. It then rises ( about 22")to the underside of the rear deck, loops around and then down to the exhaust fitting on the transom. Be certain the exhaust is well supported and secured. The exhaust should exit the hull a few inches above the waterline.
________
Drug Test
Last edited by Ron M. on Feb 11th, '11, 06:00, edited 1 time in total.
Check the Westerbeke site
Download the Westerbeke installation manual document #43268. It shows how to install a system that is less likely to have problems.
Generally the exhaust hose should rise to the the highest point possible and then head down immediately before exiting the boat.
Be careful in locating the exit hole. My boats stern squats about 12" from its resting position when its under power or driven by sails. This change in angle when the hull is driven is a normal response by a displacement hull. My exhaust output is about 12" above the resting waterline and dead even or slightly below the water line when motoring at 80% power. You want to avoid the exhaust opening below the waterline under any circumstances.
One way water can get back into the engine is not having a large enough water lift muffler. When the boat rocks with the engine off water that is in the system runs back and fills the muffler. If it isn't large enough to hold it all then it can come back into the engine. A typical situation would be when you are sailing downwind and get a wave slap in the stern. The water level at the stern rises above the exhaust outlet and the boat tilts forward.
Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.
Generally the exhaust hose should rise to the the highest point possible and then head down immediately before exiting the boat.
Be careful in locating the exit hole. My boats stern squats about 12" from its resting position when its under power or driven by sails. This change in angle when the hull is driven is a normal response by a displacement hull. My exhaust output is about 12" above the resting waterline and dead even or slightly below the water line when motoring at 80% power. You want to avoid the exhaust opening below the waterline under any circumstances.
One way water can get back into the engine is not having a large enough water lift muffler. When the boat rocks with the engine off water that is in the system runs back and fills the muffler. If it isn't large enough to hold it all then it can come back into the engine. A typical situation would be when you are sailing downwind and get a wave slap in the stern. The water level at the stern rises above the exhaust outlet and the boat tilts forward.
Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.