Converting a dry exhaust to wet.

Does this design with VETUS 40 muffler brings any back pressure ?

 

NO, not noticeable.

 

Just read this Nikos before starting to work

http://www.proboat-digital.com/proboat/20070607/

page 94 "reducing the risk"
With special attention to page 98 on water lift muffler and elbow
It will help you deciding



And thanks apex as he brought this link to us

 

Forget about that, quickly! We are talking about a open little fishboat!

 

Variable geometry

 

What if?

I showed my drawing to a friend and he told me: why the muffler under waterline? Then I thought that all that I read on the net were about waterlift mufflers, which is not the case here. So what if I make the arrangement showed here? It 's much simpler and I think that there will be no back pressure issue. I'll do some measurements next time that I 'll be at the boat (in about a week) to see that everything fits. What do you think?
Regards, Nikos.

 

Looks better

Check if you can Get rid of MP40 as a water lift muffler is not efficient, inject water as close as possible to the head with small droplets and avoid to sharp radius on all the line, spit exhaust at the stern as far as possible of objects (like rudder) that can reflect the sound to you, put a good oiled cotton wire mesh air filter (like for tuning on cars). Have an Ouzo ...

 

Shut up ! layman !
all complete nonense (as usual), except for the Ouzo.

 

Right, the higher you have the muffler the less resistance naturally. The most commercial systems work well below waterline though. look at the pictures below. (copyright Vetus) The left one is like your arrangement. And I doubt you need any additional muffler if you make a mixing elbow like I sketched.
You did not show a elbow near the through hull outlet but I assume there will be one!?

Regards
Richard

 

Whow ! You speak Vetus fluently !

Shut up= Rude behaviour
Layman = Amateur from Latin "amator" = a guy that love what he does.
i agree with you

 

I think I' ll skip the elbow near the through hull. The hose after the muffler has a gentle slope downwards, so I hope that 'll do! I don 't have the room for an elbow anyway...

 

Ok Nikos, Hammer this together and you can save the money for the muffler too. (if its still too loud, you can always add a muffler later) but it should do the trick...
The angle is something around 30° to 50° , make shure that the outlet is some 2 cm higher than the incoming pipe at the angle you install the barrel.
And make the outlet hose some mm wider than the incoming exh. pipe, thats adds to baffle the sound.

Regards
Richard

 

You are really a pain in the bu...! What drives you to mix up every serious thread with your drivel? And what sort of "advice" is this: "inject water as close as possible to the head"? Are you nuts? Stay away from the cyl. head with water, as far as possible!
Here is one giving real valuable advice, and this was mentioned by well respected members above. No need for your unmature and sometimes dangerous phantasies. Go play with your nonsense on your outer space threads.

Sasha

 

If the height angle of the exhaust pipe from the the elbow to the hull is close, simply use a rubber exhaust flap on the thru hull fitting and angle the hinge so that if slow the boat the water pressure will close the exhaust (the exhaust pressure will force it open enough to let the exhaust escape)

 

You 're right. I 've though of that. I' ll have to do some measurements next time I 'll go to the boat to decide what I 'm going to do.
I 'll keep in touch with any progress.