Exhaust flap/cover.

[Huttoft]

Does anyone have any experience of an exhaust flap/cover being fitted on the exit of their exhausts?
It sometimes crosses my mind that one might be a help against a following sea entering the exhaust and then overcoming the "swan-neck" and then damaging the engine.
Something on the lines of what is sometimes seen on a tractor's or truck's vertical exhaust pipe.
Any thoughts as to practicality?
Where was it sourced from?
Good luck.

 

[CCJ]

What about the water in the water trap when the boat goes down a steep wave

 

[Tranona]

They are commonly used on power boats with straight through exhausts, but are really unnecessary on a sailing boat with decent swan neck and a water trap just aft of the engine exhaust outlet. However they are available on a check valve transom outlet from Vetus type TRCPV for small diameter hose. They are intended for motor boats with low aft decks or where a swan neck is not feasible.

 

[scottie]

Way back it was common to use elastomuffle silencers as a form of no return valve ,they consist of a neoprene cone with slits that open to allow the exhaust through under pressure and then contract and close ,however they eventually loose their elasticity and leak . I took doom time to work out why the engines were back filling but they did work well when new

 

[scottie]

Flaps were used in V6/8 outdrives with separate exhausts as was not unknown for flooding to occur when closing the throttle and the back of the boat to sit down into the stern wave ��