Quiter Exhaust

[Pete]

Have a 1976 48 LRC with 453N Detroits. In love with the boat, the engines, everything about it. But even in blind love, you can have an occassional wish and in my case it would be for a quiter exhaust. The exhaust is a mere 4 inches and the mufflers are out in the open in the engine room. So I have space, especially in height. Apparently, there have been great advances with mufflers, as I walk by more current Hatteras with giant engines compared to mine and they are so quite these days. The current mufflers are Vernatone, about 36 to 40 inches long (have not measured). Is there an upgrade out there somewhere that will let the engines breathe as they must but cut down on the noise? BTW, the mufflers are in good condition. My boat is no noiser than all the other N series DD Hatteras of its vintage. Thanks

Pete Drez

 

[Genesis]

Its the Detroits that make 'em noisy.......

 

[Capt K]

Here, in Connecticut, at this time of year, I wish I had a recording of my Detroits! I really miss that sound.

K

 

[SKYCHENEY]

I think you could quiet them some, but as Genesis stated, those 2-cycle Detroits are inherently noisey. I would call Hatteras and ask them first. Obviously, you will need to have the exhaust engineered to make sure you don't restrict it too much and cause unwanted back pressure. If you don't get anywhere with Hatteras, try Detroit Diesel next. Maybe they have done this before. It's worth a couple of phone calls to find out.

 

[NAN-PO 41]

A 53 series Detroit has to be the noisiest engine ever made. I have twin 8v53n's and their exhaust noise would wake the dead. They have huge mufflers and it sounds like they don't have any.
That being said I must admit that I love my Detroits noisy or not. They will run forever if given the proper care. Enjoy your boat but you will probably have to live with the noise.
Fred

 

[luckydave215]

My boat (1271ti's) is very quiet. It has two mufflers per side, each about 20" diameter X 8' long. At slow cruise, 1100rpm, 11 knots, you can hardly hear the exuasts from the (open) bridge. At 1900rpm, 17 knots, you can hear them, but it's still prety quiet. All the series I 60's I've seen have the same setup, so I believe it's stock. It sure works!

 

[mike]

Luckydave215, you said in the previous post the you have two per side at 8'; does this mean each side has 16' of muffler at 20" in dia.? Can you post some pics. of your set-up? tx, mike

 

[luckydave215]

I don't have any pics to post, but 16' of muffler per side is about right. (I haven't actually measured them) I have a 60' sport fish, and the mufflers start in the engine room and end at the transom.

 

[mike]

Dave, by chance are you originally from the sf bay area? mike

 

[REBrueckner]

Besides DD and Hatteras and maybe Sam's, you can also search online for marine mufflers and query a few. Exhaust hose rather than fiberglass glass tubing is supposedly quieter, so maybe that's also a step you can consider if your boat uses glass. But that would likely affect interior noise levels more than stern exhaust noise levels I would think. Finally you can check to see if larger diameter exhausts reduce noise levels....I don't know what the trade offs would be but those in the business should know...This would likely be a rather expensive alternative, last on the list in my opinion.
Although unlikely, are you sure you are pumping normal salt water volumes at cruise speed? In other words, dockside at idle you might sound like others, but underway be nosier.
Ket us know what you conclude.

 

[luckydave215]

Mike, I'm from Del Mar ca. (San Diego Yacht Club brat, my father was a life member, I sort of grew up there).

 

[SKYCHENEY]

Good point about water volumes. Have you ever checked the exhaust temps? Maybe there is some restriction in the system. Are other 48's with 453's just as loud or is this particular boat noisier?

 

[AquaNav77]

If in need for a quieter exhaust system, check with Marine Exhaust Systems of Riviera Beach, FL. At the Fort Lauderdale Boat Show last November, I noticed that on the new Hat's the exhausts were manufactured by this company. I have also heard excellent reviews from people that have repowered as well.

Jim

 

[Pete]

Thanks to all for the feedback. I will lookup Marine Exhaust Systems of Riviera Beach, FL, at the Miami Show, and see if they have any ideas. As for my exhaust versus similar boats, it is the same. And the noise is most annoying at the dock. Once you get going, you can not hear it at all from the pilot house or flybridge. But I go into the cockpit every hour or two to check for exhaust water flow and to do an engine room check underway. It is loud and clear in the cockpit, with max volume when I lean over to check the water flow. BTW, I did a sound level reading at all the places tested in the Boating article available on Sam's site, and my readings were a little better in all cases, as they should be since the engine room has a layer of lead lined insulation on the ceiling. Just would be nice to not wake up the marina when I leave at first light, as I often do since at 8.5 knots it takes a while to get anywhere.

 

[AquaNav77]

Another source would be DeAngelo Exhaust Systems of Ft. Lauderdale. Both DeAngelo and Marine Exhaust of Riviera Beach will be at the Miami Show along with others such as Centek, Soundown, and others.

Jim