Quieting Down Exhaust of 6-71's

[spartonboat1]

The older Hatt's with DD's, e.g. 6-71's, in this 6-71N in a 1972 43', have an exhaust note that I find pleasing, i.e. Screamin' Jimmy and all that. But they are noisy on a run, again, does not bother me too much. But is there a muffler or re-direction device that would shift the sound into the water somewhat.

Curious...

 

[Play'N Hooky Too]

For my 8V71TIs I fabricated a couple of custom angled exhaust deflectors using Schedule-10 316 stainless pipe. I don't know if it was because of my hard top or some other factor, but at cruising speed the reverberation from the exhaust was like driving your car at 70 mph with one window down.

They basically just deflect the exhaust down at about a 30 degree angle. Has made a big difference in cutting down the reverberation.

 

[jap201]

nice job. my 32 blackfin with cumins had something similar but made with what I think was pvc. that was a very quiet boat.

 

[Captain Ralph]

Used 10" rubber 90s. Still loud but that howl and ear ringer has been greatly reduced.

Just sent a query to DeAngelo about a cartridge that could be placed into the tail pipe.
They have the query and thinking about it and other options.

 

[SeaEric]

I was on the Soundown site looking at insuation. They seem to have a line of mufflers that I may investigate.

 

[Canuck Dennis]

Change the regular in line mufflers to inline water lift. They are available

 

[BOATER BOB]

Put some Turbos on and it will be quieter !

 

[brettportzer]

Change the regular in line mufflers to inline water lift. They are available

In an earlier thread you said you were going to be doing that to your boat, did you do it, and how did it work out?

 

[Dan Mapes]

Put some Turbos on and it will be quieter !

When we had Freedom with yes, TI's, at some RPMs it boomed. I think it was worst around 1300. It was actually pretty good a 1800+ RPMS while hauling the mail. Changing to lift mufflers would seem to be a genuine chore on this hull. While ours was an 85 43' MY I think the hull was the same.

 

[Canuck Dennis]

Was going to and then decided to sell instead, would have needed some minor carpentry work which was holding up the decision to go and could not find anyone available. So, sold instead.

 

[spartonboat1]

Change the regular in line mufflers to inline water lift. They are available

Interesting thought, since I believe my Onan Genset exhausts through a "water lift" muffler arrangement.

 

[JD5652]

I have heard of positive feedback from the Soundown modification...

Exhaust Silencers - Soundown Products - Soundown Products